ansible-hardening/doc/source/rhel6stig.csv

1	id	severity	title	description	iacontrols	ruleID	fixid	fixtext	checkid	checktext
2	V-38612	medium	The SSH daemon must not allow host-based authentication.	SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.	None	SV-50413r1_rule	F-43560r1_fix	SSH's cryptographic host-based authentication is more secure than ".rhosts" authentication, since hosts are cryptographically authenticated. However, it is not recommended that hosts unilaterally trust one another, even within an organization. To disable host-based authentication, add or correct the following line in "/etc/ssh/sshd_config": HostbasedAuthentication no	C-46170r1_chk	To determine how the SSH daemon's "HostbasedAuthentication" option is set, run the following command: # grep -i HostbasedAuthentication /etc/ssh/sshd_config If no line, a commented line, or a line indicating the value "no" is returned, then the required value is set. If the required value is not set, this is a finding.
3	V-38580	medium	The audit system must be configured to audit the loading and unloading of dynamic kernel modules.	The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.	None	SV-50381r2_rule	F-43528r2_fix	Add the following to "/etc/audit/audit.rules" in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system: -w /sbin/insmod -p x -k modules -w /sbin/rmmod -p x -k modules -w /sbin/modprobe -p x -k modules -a always,exit -F arch=[ARCH] -S init_module -S delete_module -k modules	C-46138r3_chk	To determine if the system is configured to audit execution of module management programs, run the following commands: $ sudo egrep -e "(-w |-F path=)/sbin/insmod" /etc/audit/audit.rules $ sudo egrep -e "(-w |-F path=)/sbin/rmmod" /etc/audit/audit.rules $ sudo egrep -e "(-w |-F path=)/sbin/modprobe" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "init_module" system call, run the following command: $ sudo grep -w "init_module" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "delete_module" system call, run the following command: $ sudo grep -w "delete_module" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If no line is returned for any of these commands, this is a finding.
4	V-38459	medium	The /etc/group file must be group-owned by root.	The "/etc/group" file contains information regarding groups that are configured on the system. Protection of this file is important for system security.	None	SV-50259r1_rule	F-43404r1_fix	To properly set the group owner of "/etc/group", run the command: # chgrp root /etc/group	C-46014r1_chk	To check the group ownership of "/etc/group", run the command: $ ls -l /etc/group If properly configured, the output should indicate the following group-owner. "root" If it does not, this is a finding.
5	V-38649	low	The system default umask for the csh shell must be 077.	The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and/or written to by unauthorized users.	None	SV-50450r1_rule	F-43598r1_fix	To ensure the default umask for users of the C shell is set properly, add or correct the "umask" setting in "/etc/csh.cshrc" to read as follows: umask 077	C-46209r1_chk	Verify the "umask" setting is configured correctly in the "/etc/csh.cshrc" file by running the following command: # grep "umask" /etc/csh.cshrc All output must show the value of "umask" set to 077, as shown in the below: # grep "umask" /etc/csh.cshrc umask 077 If the above command returns no output, or if the umask is configured incorrectly, this is a finding.
6	V-38648	low	The qpidd service must not be running.	The qpidd service is automatically installed when the "base" package selection is selected during installation. The qpidd service listens for network connections which increases the attack surface of the system. If the system is not intended to receive AMQP traffic then the "qpidd" service is not needed and should be disabled or removed.	None	SV-50449r2_rule	F-43597r2_fix	The "qpidd" service provides high speed, secure, guaranteed delivery services. It is an implementation of the Advanced Message Queuing Protocol. By default the qpidd service will bind to port 5672 and listen for connection attempts. The "qpidd" service can be disabled with the following commands: # chkconfig qpidd off # service qpidd stop	C-46208r2_chk	To check that the "qpidd" service is disabled in system boot configuration, run the following command: # chkconfig "qpidd" --list Output should indicate the "qpidd" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "qpidd" --list "qpidd" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "qpidd" is disabled through current runtime configuration: # service qpidd status If the service is disabled the command will return the following output: qpidd is stopped If the service is running, this is a finding.
7	V-38643	medium	There must be no world-writable files on the system.	Data in world-writable files can be modified by any user on the system. In almost all circumstances, files can be configured using a combination of user and group permissions to support whatever legitimate access is needed without the risk caused by world-writable files.	None	SV-50444r3_rule	F-43591r1_fix	It is generally a good idea to remove global (other) write access to a file when it is discovered. However, check with documentation for specific applications before making changes. Also, monitor for recurring world-writable files, as these may be symptoms of a misconfigured application or user account.	C-46202r3_chk	To find world-writable files, run the following command for each local partition [PART], excluding special filesystems such as /selinux, /proc, or /sys: # find [PART] -xdev -type f -perm -002 If there is output, this is a finding.
8	V-38642	low	The system default umask for daemons must be 027 or 022.	The umask influences the permissions assigned to files created by a process at run time. An unnecessarily permissive umask could result in files being created with insecure permissions.	None	SV-50443r1_rule	F-43592r1_fix	The file "/etc/init.d/functions" includes initialization parameters for most or all daemons started at boot time. The default umask of 022 prevents creation of group- or world-writable files. To set the default umask for daemons, edit the following line, inserting 022 or 027 for [UMASK] appropriately: umask [UMASK] Setting the umask to too restrictive a setting can cause serious errors at runtime. Many daemons on the system already individually restrict themselves to a umask of 077 in their own init scripts.	C-46203r1_chk	To check the value of the "umask", run the following command: $ grep umask /etc/init.d/functions The output should show either "022" or "027". If it does not, this is a finding.
9	V-38641	low	The atd service must be disabled.	The "atd" service could be used by an unsophisticated insider to carry out activities outside of a normal login session, which could complicate accountability. Furthermore, the need to schedule tasks with "at" or "batch" is not common.	None	SV-50442r2_rule	F-43590r2_fix	The "at" and "batch" commands can be used to schedule tasks that are meant to be executed only once. This allows delayed execution in a manner similar to cron, except that it is not recurring. The daemon "atd" keeps track of tasks scheduled via "at" and "batch", and executes them at the specified time. The "atd" service can be disabled with the following commands: # chkconfig atd off # service atd stop	C-46201r2_chk	If the system uses the "atd" service, this is not applicable. To check that the "atd" service is disabled in system boot configuration, run the following command: # chkconfig "atd" --list Output should indicate the "atd" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "atd" --list "atd" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "atd" is disabled through current runtime configuration: # service atd status If the service is disabled the command will return the following output: atd is stopped If the service is running, this is a finding.
10	V-38640	low	The Automatic Bug Reporting Tool (abrtd) service must not be running.	Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the local machine, as well as sensitive information from within a process's address space or registers.	None	SV-50441r2_rule	F-43589r2_fix	The Automatic Bug Reporting Tool ("abrtd") daemon collects and reports crash data when an application crash is detected. Using a variety of plugins, abrtd can email crash reports to system administrators, log crash reports to files, or forward crash reports to a centralized issue tracking system such as RHTSupport. The "abrtd" service can be disabled with the following commands: # chkconfig abrtd off # service abrtd stop	C-46200r1_chk	To check that the "abrtd" service is disabled in system boot configuration, run the following command: # chkconfig "abrtd" --list Output should indicate the "abrtd" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "abrtd" --list "abrtd" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "abrtd" is disabled through current runtime configuration: # service abrtd status If the service is disabled the command will return the following output: abrtd is stopped If the service is running, this is a finding.
11	V-38647	low	The system default umask in /etc/profile must be 077.	The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and/or written to by unauthorized users.	None	SV-50448r1_rule	F-43596r1_fix	To ensure the default umask controlled by "/etc/profile" is set properly, add or correct the "umask" setting in "/etc/profile" to read as follows: umask 077	C-46207r1_chk	Verify the "umask" setting is configured correctly in the "/etc/profile" file by running the following command: # grep "umask" /etc/profile All output must show the value of "umask" set to 077, as shown in the below: # grep "umask" /etc/profile umask 077 If the above command returns no output, or if the umask is configured incorrectly, this is a finding.
12	V-38646	low	The oddjobd service must not be running.	The "oddjobd" service may provide necessary functionality in some environments but it can be disabled if it is not needed. Execution of tasks by privileged programs, on behalf of unprivileged ones, has traditionally been a source of privilege escalation security issues.	None	SV-50447r2_rule	F-43595r2_fix	The "oddjobd" service exists to provide an interface and access control mechanism through which specified privileged tasks can run tasks for unprivileged client applications. Communication with "oddjobd" is through the system message bus. The "oddjobd" service can be disabled with the following commands: # chkconfig oddjobd off # service oddjobd stop	C-46206r2_chk	To check that the "oddjobd" service is disabled in system boot configuration, run the following command: # chkconfig "oddjobd" --list Output should indicate the "oddjobd" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "oddjobd" --list "oddjobd" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "oddjobd" is disabled through current runtime configuration: # service oddjobd status If the service is disabled the command will return the following output: oddjobd is stopped If the service is running, this is a finding.
13	V-38645	low	The system default umask in /etc/login.defs must be 077.	The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and/or written to by unauthorized users.	None	SV-50446r1_rule	F-43594r1_fix	To ensure the default umask controlled by "/etc/login.defs" is set properly, add or correct the "umask" setting in "/etc/login.defs" to read as follows: UMASK 077	C-46205r1_chk	Verify the "umask" setting is configured correctly in the "/etc/login.defs" file by running the following command: # grep -i "umask" /etc/login.defs All output must show the value of "umask" set to 077, as shown in the below: # grep -i "umask" /etc/login.defs UMASK 077 If the above command returns no output, or if the umask is configured incorrectly, this is a finding.
14	V-38644	low	The ntpdate service must not be running.	The "ntpdate" service may only be suitable for systems which are rebooted frequently enough that clock drift does not cause problems between reboots. In any event, the functionality of the ntpdate service is now available in the ntpd program and should be considered deprecated.	None	SV-50445r2_rule	F-43593r2_fix	The ntpdate service sets the local hardware clock by polling NTP servers when the system boots. It synchronizes to the NTP servers listed in "/etc/ntp/step-tickers" or "/etc/ntp.conf" and then sets the local hardware clock to the newly synchronized system time. The "ntpdate" service can be disabled with the following commands: # chkconfig ntpdate off # service ntpdate stop	C-46204r1_chk	To check that the "ntpdate" service is disabled in system boot configuration, run the following command: # chkconfig "ntpdate" --list Output should indicate the "ntpdate" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "ntpdate" --list "ntpdate" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "ntpdate" is disabled through current runtime configuration: # service ntpdate status If the service is disabled the command will return the following output: ntpdate is stopped If the service is running, this is a finding.
15	V-51369	low	The system must use a Linux Security Module configured to limit the privileges of system services.	Setting the SELinux policy to "targeted" or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services.	None	SV-65579r1_rule	F-56171r1_fix	The SELinux "targeted" policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in "/etc/selinux/config": SELINUXTYPE=targeted Other policies, such as "mls", provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.	C-53711r1_chk	Check the file "/etc/selinux/config" and ensure the following line appears: SELINUXTYPE=targeted If it does not, this is a finding.
16	V-38452	low	The system package management tool must verify permissions on all files and directories associated with packages.	Permissions on system binaries and configuration files that are too generous could allow an unauthorized user to gain privileges that they should not have. The permissions set by the vendor should be maintained. Any deviations from this baseline should be investigated.	None	SV-50252r1_rule	F-43398r1_fix	The RPM package management system can restore file access permissions of package files and directories. The following command will update permissions on files and directories with permissions different from what is expected by the RPM database: # rpm --setperms [package]	C-46008r1_chk	The following command will list which files and directories on the system have permissions different from what is expected by the RPM database: # rpm -Va | grep '^.M' If there is any output, for each file or directory found, find the associated RPM package and compare the RPM-expected permissions with the actual permissions on the file or directory: # rpm -qf [file or directory name] # rpm -q --queryformat "[%{FILENAMES} %{FILEMODES:perms}\n]" [package] | grep [filename] # ls -lL [filename] If the existing permissions are more permissive than those expected by RPM, this is a finding.
17	V-38551	medium	The operating system must connect to external networks or information systems only through managed IPv6 interfaces consisting of boundary protection devices arranged in accordance with an organizational security architecture.	The "ip6tables" service provides the system's host-based firewalling capability for IPv6 and ICMPv6.	None	SV-50352r3_rule	F-43499r2_fix	The "ip6tables" service can be enabled with the following commands: # chkconfig ip6tables on # service ip6tables start	C-46109r3_chk	If the system is a cross-domain system, this is not applicable. If IPV6 is disabled, this is not applicable. Run the following command to determine the current status of the "ip6tables" service: # service ip6tables status If the service is not running, it should return the following: ip6tables: Firewall is not running. If the service is not running, this is a finding.
18	V-51363	medium	The system must use a Linux Security Module configured to enforce limits on system services.	Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.	None	SV-65573r1_rule	F-56165r1_fix	The SELinux state should be set to "enforcing" at system boot time. In the file "/etc/selinux/config", add or correct the following line to configure the system to boot into enforcing mode: SELINUX=enforcing	C-53703r1_chk	Check the file "/etc/selinux/config" and ensure the following line appears: SELINUX=enforcing If SELINUX is not set to enforcing, this is a finding.
19	V-38453	low	The system package management tool must verify group-ownership on all files and directories associated with packages.	Group-ownership of system binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The group-ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.	None	SV-50253r1_rule	F-43399r1_fix	The RPM package management system can restore group-ownership of the package files and directories. The following command will update files and directories with group-ownership different from what is expected by the RPM database: # rpm -qf [file or directory name] # rpm --setugids [package]	C-46009r1_chk	The following command will list which files on the system have group-ownership different from what is expected by the RPM database: # rpm -Va | grep '^......G' If there is output, this is a finding.
20	V-38608	low	The SSH daemon must set a timeout interval on idle sessions.	Causing idle users to be automatically logged out guards against compromises one system leading trivially to compromises on another.	None	SV-50409r1_rule	F-43556r1_fix	SSH allows administrators to set an idle timeout interval. After this interval has passed, the idle user will be automatically logged out. To set an idle timeout interval, edit the following line in "/etc/ssh/sshd_config" as follows: ClientAliveInterval [interval] The timeout [interval] is given in seconds. To have a timeout of 15 minutes, set [interval] to 900. If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made here. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.	C-46167r1_chk	Run the following command to see what the timeout interval is: # grep ClientAliveInterval /etc/ssh/sshd_config If properly configured, the output should be: ClientAliveInterval 900 If it is not, this is a finding.
21	V-38499	medium	The /etc/passwd file must not contain password hashes.	The hashes for all user account passwords should be stored in the file "/etc/shadow" and never in "/etc/passwd", which is readable by all users.	None	SV-50300r1_rule	F-43446r1_fix	If any password hashes are stored in "/etc/passwd" (in the second field, instead of an "x"), the cause of this misconfiguration should be investigated. The account should have its password reset and the hash should be properly stored, or the account should be deleted entirely.	C-46056r1_chk	To check that no password hashes are stored in "/etc/passwd", run the following command: # awk -F: '($2 != "x") {print}' /etc/passwd If it produces any output, then a password hash is stored in "/etc/passwd". If any stored hashes are found in /etc/passwd, this is a finding.
22	V-38450	medium	The /etc/passwd file must be owned by root.	The "/etc/passwd" file contains information about the users that are configured on the system. Protection of this file is critical for system security.	None	SV-50250r1_rule	F-43395r1_fix	To properly set the owner of "/etc/passwd", run the command: # chown root /etc/passwd	C-46005r1_chk	To check the ownership of "/etc/passwd", run the command: $ ls -l /etc/passwd If properly configured, the output should indicate the following owner: "root" If it does not, this is a finding.
23	V-38581	medium	The system boot loader configuration file(s) must be group-owned by root.	The "root" group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.	None	SV-50382r1_rule	F-43529r1_fix	The file "/etc/grub.conf" should be group-owned by the "root" group to prevent destruction or modification of the file. To properly set the group owner of "/etc/grub.conf", run the command: # chgrp root /etc/grub.conf	C-46139r1_chk	To check the group ownership of "/etc/grub.conf", run the command: $ ls -lL /etc/grub.conf If properly configured, the output should indicate the following group-owner. "root" If it does not, this is a finding.
24	V-38451	medium	The /etc/passwd file must be group-owned by root.	The "/etc/passwd" file contains information about the users that are configured on the system. Protection of this file is critical for system security.	None	SV-50251r1_rule	F-43396r1_fix	To properly set the group owner of "/etc/passwd", run the command: # chgrp root /etc/passwd	C-46006r1_chk	To check the group ownership of "/etc/passwd", run the command: $ ls -l /etc/passwd If properly configured, the output should indicate the following group-owner. "root" If it does not, this is a finding.
25	V-38458	medium	The /etc/group file must be owned by root.	The "/etc/group" file contains information regarding groups that are configured on the system. Protection of this file is important for system security.	None	SV-50258r1_rule	F-43403r1_fix	To properly set the owner of "/etc/group", run the command: # chown root /etc/group	C-46013r1_chk	To check the ownership of "/etc/group", run the command: $ ls -l /etc/group If properly configured, the output should indicate the following owner: "root" If it does not, this is a finding.
26	V-38447	low	The system package management tool must verify contents of all files associated with packages.	The hash on important files like system executables should match the information given by the RPM database. Executables with erroneous hashes could be a sign of nefarious activity on the system.	None	SV-50247r2_rule	F-43392r1_fix	The RPM package management system can check the hashes of installed software packages, including many that are important to system security. Run the following command to list which files on the system have hashes that differ from what is expected by the RPM database: # rpm -Va | grep '^..5' A "c" in the second column indicates that a file is a configuration file, which may appropriately be expected to change. If the file that has changed was not expected to then refresh from distribution media or online repositories. rpm -Uvh [affected_package] OR yum reinstall [affected_package]	C-46002r3_chk	The following command will list which files on the system have file hashes different from what is expected by the RPM database. # rpm -Va | awk '$1 ~ /..5/ && $2 != "c"' If there is output, this is a finding.
27	V-38658	medium	The system must prohibit the reuse of passwords within twenty-four iterations.	Preventing reuse of previous passwords helps ensure that a compromised password is not reused by a user.	None	SV-50459r1_rule	F-43608r1_fix	Do not allow users to reuse recent passwords. This can be accomplished by using the "remember" option for the "pam_unix" PAM module. In the file "/etc/pam.d/system-auth", append "remember=24" to the line which refers to the "pam_unix.so" module, as shown: password sufficient pam_unix.so [existing_options] remember=24 The DoD requirement is 24 passwords.	C-46219r1_chk	To verify the password reuse setting is compliant, run the following command: $ grep remember /etc/pam.d/system-auth The output should show the following at the end of the line: remember=24 If it does not, this is a finding.
28	V-38659	low	The operating system must employ cryptographic mechanisms to protect information in storage.	The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.	None	SV-50460r1_rule	F-43609r1_fix	Red Hat Enterprise Linux 6 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time. For manual installations, select the "Encrypt" checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots. For automated/unattended installations, it is possible to use Kickstart by adding the "--encrypted" and "--passphrase=" options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition: part / --fstype=ext3 --size=100 --onpart=hda1 --encrypted --passphrase=[PASSPHRASE] Any [PASSPHRASE] is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the "--passphrase=" option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation. Detailed information on encrypting partitions using LUKS can be found on the Red Had Documentation web site: https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-Security_Guide-LUKS_Disk_Encryption.html	C-46220r1_chk	Determine if encryption must be used to protect data on the system. If encryption must be used and is not employed, this is a finding.
29	V-38582	medium	The xinetd service must be disabled if no network services utilizing it are enabled.	The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.	None	SV-50383r2_rule	F-43530r2_fix	The "xinetd" service can be disabled with the following commands: # chkconfig xinetd off # service xinetd stop	C-46140r2_chk	If network services are using the xinetd service, this is not applicable. To check that the "xinetd" service is disabled in system boot configuration, run the following command: # chkconfig "xinetd" --list Output should indicate the "xinetd" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "xinetd" --list "xinetd" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "xinetd" is disabled through current runtime configuration: # service xinetd status If the service is disabled the command will return the following output: xinetd is stopped If the service is running, this is a finding.
30	V-38650	low	The rdisc service must not be running.	General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information.	None	SV-50451r2_rule	F-43599r2_fix	The "rdisc" service implements the client side of the ICMP Internet Router Discovery Protocol (IRDP), which allows discovery of routers on the local subnet. If a router is discovered then the local routing table is updated with a corresponding default route. By default this daemon is disabled. The "rdisc" service can be disabled with the following commands: # chkconfig rdisc off # service rdisc stop	C-46210r1_chk	To check that the "rdisc" service is disabled in system boot configuration, run the following command: # chkconfig "rdisc" --list Output should indicate the "rdisc" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "rdisc" --list "rdisc" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "rdisc" is disabled through current runtime configuration: # service rdisc status If the service is disabled the command will return the following output: rdisc is stopped If the service is running, this is a finding.
31	V-38651	low	The system default umask for the bash shell must be 077.	The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and/or written to by unauthorized users.	None	SV-50452r1_rule	F-43600r1_fix	To ensure the default umask for users of the Bash shell is set properly, add or correct the "umask" setting in "/etc/bashrc" to read as follows: umask 077	C-46211r1_chk	Verify the "umask" setting is configured correctly in the "/etc/bashrc" file by running the following command: # grep "umask" /etc/bashrc All output must show the value of "umask" set to 077, as shown below: # grep "umask" /etc/bashrc umask 077 umask 077 If the above command returns no output, or if the umask is configured incorrectly, this is a finding.
32	V-38652	medium	Remote file systems must be mounted with the nodev option.	Legitimate device files should only exist in the /dev directory. NFS mounts should not present device files to users.	None	SV-50453r2_rule	F-43601r1_fix	Add the "nodev" option to the fourth column of "/etc/fstab" for the line which controls mounting of any NFS mounts.	C-46212r2_chk	To verify the "nodev" option is configured for all NFS mounts, run the following command: $ mount | grep "nfs " All NFS mounts should show the "nodev" setting in parentheses, along with other mount options. If the setting does not show, this is a finding.
33	V-38653	high	The snmpd service must not use a default password.	Presence of the default SNMP password enables querying of different system aspects and could result in unauthorized knowledge of the system.	None	SV-50454r1_rule	F-43602r1_fix	Edit "/etc/snmp/snmpd.conf", remove default community string "public". Upon doing that, restart the SNMP service: # service snmpd restart	C-46213r1_chk	To ensure the default password is not set, run the following command: # grep -v "^#" /etc/snmp/snmpd.conf| grep public There should be no output. If there is output, this is a finding.
34	V-38654	medium	Remote file systems must be mounted with the nosuid option.	NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables should be installed to their default location on the local filesystem.	None	SV-50455r2_rule	F-43603r1_fix	Add the "nosuid" option to the fourth column of "/etc/fstab" for the line which controls mounting of any NFS mounts.	C-46214r3_chk	To verify the "nosuid" option is configured for all NFS mounts, run the following command: $ mount | grep nfs All NFS mounts should show the "nosuid" setting in parentheses, along with other mount options. If the setting does not show, this is a finding.
35	V-38490	medium	The operating system must enforce requirements for the connection of mobile devices to operating systems.	USB storage devices such as thumb drives can be used to introduce unauthorized software and other vulnerabilities. Support for these devices should be disabled and the devices themselves should be tightly controlled.	None	SV-50291r4_rule	F-43437r3_fix	To prevent USB storage devices from being used, configure the kernel module loading system to prevent automatic loading of the USB storage driver. To configure the system to prevent the "usb-storage" kernel module from being loaded, add the following line to a file in the directory "/etc/modprobe.d": install usb-storage /bin/true This will prevent the "modprobe" program from loading the "usb-storage" module, but will not prevent an administrator (or another program) from using the "insmod" program to load the module manually.	C-46047r3_chk	If the system is configured to prevent the loading of the "usb-storage" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated"/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r usb-storage /etc/modprobe.conf /etc/modprobe.d If no line is returned, this is a finding.
36	V-38656	low	The system must use SMB client signing for connecting to samba servers using smbclient.	Packet signing can prevent man-in-the-middle attacks which modify SMB packets in transit.	None	SV-50457r1_rule	F-43606r1_fix	To require samba clients running "smbclient" to use packet signing, add the following to the "[global]" section of the Samba configuration file in "/etc/samba/smb.conf": client signing = mandatory Requiring samba clients such as "smbclient" to use packet signing ensures they can only communicate with servers that support packet signing.	C-46217r1_chk	To verify that Samba clients running smbclient must use packet signing, run the following command: # grep signing /etc/samba/smb.conf The output should show: client signing = mandatory If it is not, this is a finding.
37	V-38657	low	The system must use SMB client signing for connecting to samba servers using mount.cifs.	Packet signing can prevent man-in-the-middle attacks which modify SMB packets in transit.	None	SV-50458r2_rule	F-43607r1_fix	Require packet signing of clients who mount Samba shares using the "mount.cifs" program (e.g., those who specify shares in "/etc/fstab"). To do so, ensure signing options (either "sec=krb5i" or "sec=ntlmv2i") are used. See the "mount.cifs(8)" man page for more information. A Samba client should only communicate with servers who can support SMB packet signing.	C-46218r4_chk	If Samba is not in use, this is not applicable. To verify that Samba clients using mount.cifs must use packet signing, run the following command: # grep sec /etc/fstab /etc/mtab The output should show either "krb5i" or "ntlmv2i" in use. If it does not, this is a finding.
38	V-38437	low	Automated file system mounting tools must not be enabled unless needed.	All filesystems that are required for the successful operation of the system should be explicitly listed in "/etc/fstab" by an administrator. New filesystems should not be arbitrarily introduced via the automounter. The "autofs" daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as "/misc/cd". However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it is almost always possible to configure filesystem mounts statically by editing "/etc/fstab" rather than relying on the automounter.	None	SV-50237r1_rule	F-43381r1_fix	If the "autofs" service is not needed to dynamically mount NFS filesystems or removable media, disable the service for all runlevels: # chkconfig --level 0123456 autofs off Stop the service if it is already running: # service autofs stop	C-45991r1_chk	To verify the "autofs" service is disabled, run the following command: chkconfig --list autofs If properly configured, the output should be the following: autofs 0:off 1:off 2:off 3:off 4:off 5:off 6:off Verify the "autofs" service is not running: # service autofs status If the autofs service is enabled or running, this is a finding.
39	V-51379	low	All device files must be monitored by the system Linux Security Module.	If a device file carries the SELinux type "unlabeled_t", then SELinux cannot properly restrict access to the device file.	None	SV-65589r1_rule	F-56179r1_fix	Device files, which are used for communication with important system resources, should be labeled with proper SELinux types. If any device files carry the SELinux type "unlabeled_t", investigate the cause and correct the file's context.	C-53719r1_chk	To check for unlabeled device files, run the following command: # ls -RZ /dev | grep unlabeled_t It should produce no output in a well-configured system. If there is output, this is a finding.
40	V-38443	medium	The /etc/gshadow file must be owned by root.	The "/etc/gshadow" file contains group password hashes. Protection of this file is critical for system security.	None	SV-50243r1_rule	F-43388r1_fix	To properly set the owner of "/etc/gshadow", run the command: # chown root /etc/gshadow	C-45998r1_chk	To check the ownership of "/etc/gshadow", run the command: $ ls -l /etc/gshadow If properly configured, the output should indicate the following owner: "root" If it does not, this is a finding.
41	V-38526	medium	The system must not accept ICMPv4 secure redirect packets on any interface.	Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.	None	SV-50327r2_rule	F-43474r1_fix	To set the runtime status of the "net.ipv4.conf.all.secure_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.secure_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.secure_redirects = 0	C-46084r2_chk	The status of the "net.ipv4.conf.all.secure_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.secure_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.all.secure_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
42	V-38527	low	The audit system must be configured to audit all attempts to alter system time through clock_settime.	Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.	None	SV-50328r3_rule	F-43475r2_fix	On a 32-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b32 -S clock_settime -k audit_time_rules On a 64-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b64 -S clock_settime -k audit_time_rules The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules	C-46085r2_chk	To determine if the system is configured to audit calls to the "clock_settime" system call, run the following command: $ sudo grep -w "clock_settime" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If the system is not configured to audit time changes, this is a finding.
43	V-38524	medium	The system must not accept ICMPv4 redirect packets on any interface.	Accepting ICMP redirects has few legitimate uses. It should be disabled unless it is absolutely required.	None	SV-50325r2_rule	F-43472r1_fix	To set the runtime status of the "net.ipv4.conf.all.accept_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.accept_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.accept_redirects = 0	C-46082r2_chk	The status of the "net.ipv4.conf.all.accept_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.accept_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.all.accept_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
44	V-38525	low	The audit system must be configured to audit all attempts to alter system time through stime.	Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.	None	SV-50326r4_rule	F-43473r4_fix	On a 32-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b32 -S stime -k audit_time_rules On a 64-bit system, the "-S stime" is not necessary. The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules	C-46083r3_chk	If the system is 64-bit only, this is not applicable. To determine if the system is configured to audit calls to the "stime" system call, run the following command: $ sudo grep -w "stime" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If the system is not configured to audit time changes, this is a finding.
45	V-38522	low	The audit system must be configured to audit all attempts to alter system time through settimeofday.	Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.	None	SV-50323r3_rule	F-43470r2_fix	On a 32-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules On a 64-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b64 -S settimeofday -k audit_time_rules The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules	C-46080r2_chk	To determine if the system is configured to audit calls to the "settimeofday" system call, run the following command: $ sudo grep -w "settimeofday" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If the system is not configured to audit time changes, this is a finding.
46	V-38488	medium	The operating system must conduct backups of user-level information contained in the operating system per organization defined frequency to conduct backups consistent with recovery time and recovery point objectives.	Operating system backup is a critical step in maintaining data assurance and availability. User-level information is data generated by information system and/or application users. Backups shall be consistent with organizational recovery time and recovery point objectives.	None	SV-50289r1_rule	F-43435r1_fix	Procedures to back up user data from the system must be established and executed. The Red Hat operating system provides utilities for automating such a process. Commercial and open-source products are also available. Implement a process whereby user data is backed up from the system in accordance with local policies.	C-46045r1_chk	Ask an administrator if a process exists to back up user data from the system. If such a process does not exist, this is a finding.
47	V-38520	medium	The operating system must back up audit records on an organization defined frequency onto a different system or media than the system being audited.	A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.	None	SV-50321r1_rule	F-43468r1_fix	To configure rsyslog to send logs to a remote log server, open "/etc/rsyslog.conf" and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting "[loghost.example.com]" appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments. To use UDP for log message delivery: *.* @[loghost.example.com] To use TCP for log message delivery: *.* @@[loghost.example.com] To use RELP for log message delivery: *.* :omrelp:[loghost.example.com]	C-46078r1_chk	To ensure logs are sent to a remote host, examine the file "/etc/rsyslog.conf". If using UDP, a line similar to the following should be present: *.* @[loghost.example.com] If using TCP, a line similar to the following should be present: *.* @@[loghost.example.com] If using RELP, a line similar to the following should be present: *.* :omrelp:[loghost.example.com] If none of these are present, this is a finding.
48	V-38521	medium	The operating system must support the requirement to centrally manage the content of audit records generated by organization defined information system components.	A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.	None	SV-50322r1_rule	F-43656r1_fix	To configure rsyslog to send logs to a remote log server, open "/etc/rsyslog.conf" and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting "[loghost.example.com]" appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments. To use UDP for log message delivery: *.* @[loghost.example.com] To use TCP for log message delivery: *.* @@[loghost.example.com] To use RELP for log message delivery: *.* :omrelp:[loghost.example.com]	C-46269r1_chk	To ensure logs are sent to a remote host, examine the file "/etc/rsyslog.conf". If using UDP, a line similar to the following should be present: *.* @[loghost.example.com] If using TCP, a line similar to the following should be present: *.* @@[loghost.example.com] If using RELP, a line similar to the following should be present: *.* :omrelp:[loghost.example.com] If none of these are present, this is a finding.
49	V-38484	medium	The operating system, upon successful logon, must display to the user the date and time of the last logon or access via ssh.	Users need to be aware of activity that occurs regarding their account. Providing users with information regarding the date and time of their last successful login allows the user to determine if any unauthorized activity has occurred and gives them an opportunity to notify administrators. At ssh login, a user must be presented with the last successful login date and time.	None	SV-50285r2_rule	F-43431r2_fix	Update the "PrintLastLog" keyword to "yes" in /etc/ssh/sshd_config: PrintLastLog yes While it is acceptable to remove the keyword entirely since the default action for the SSH daemon is to print the last logon date and time, it is preferred to have the value explicitly documented.	C-46041r2_chk	Verify the value associated with the "PrintLastLog" keyword in /etc/ssh/sshd_config: # grep -i "^PrintLastLog" /etc/ssh/sshd_config If the "PrintLastLog" keyword is not present, this is not a finding. If the value is not set to "yes", this is a finding.
50	V-38487	low	The system package management tool must cryptographically verify the authenticity of all software packages during installation.	Ensuring all packages' cryptographic signatures are valid prior to installation ensures the provenance of the software and protects against malicious tampering.	None	SV-50288r1_rule	F-43433r1_fix	To ensure signature checking is not disabled for any repos, remove any lines from files in "/etc/yum.repos.d" of the form: gpgcheck=0	C-46043r1_chk	To determine whether "yum" has been configured to disable "gpgcheck" for any repos, inspect all files in "/etc/yum.repos.d" and ensure the following does not appear in any sections: gpgcheck=0 A value of "0" indicates that "gpgcheck" has been disabled for that repo. If GPG checking is disabled, this is a finding. If the "yum" system package management tool is not used to update the system, verify with the SA that installed packages are cryptographically signed.
51	V-38486	medium	The operating system must conduct backups of system-level information contained in the information system per organization defined frequency to conduct backups that are consistent with recovery time and recovery point objectives.	Operating system backup is a critical step in maintaining data assurance and availability. System-level information includes system-state information, operating system and application software, and licenses. Backups must be consistent with organizational recovery time and recovery point objectives.	None	SV-50287r1_rule	F-43434r1_fix	Procedures to back up OS data from the system must be established and executed. The Red Hat operating system provides utilities for automating such a process. Commercial and open-source products are also available. Implement a process whereby OS data is backed up from the system in accordance with local policies.	C-46044r1_chk	Ask an administrator if a process exists to back up OS data from the system, including configuration data. If such a process does not exist, this is a finding.
52	V-38481	medium	System security patches and updates must be installed and up-to-date.	Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities.	None	SV-50281r1_rule	F-43426r1_fix	If the system is joined to the Red Hat Network, a Red Hat Satellite Server, or a yum server, run the following command to install updates: # yum update If the system is not configured to use one of these sources, updates (in the form of RPM packages) can be manually downloaded from the Red Hat Network and installed using "rpm".	C-46036r1_chk	If the system is joined to the Red Hat Network, a Red Hat Satellite Server, or a yum server which provides updates, invoking the following command will indicate if updates are available: # yum check-update If the system is not configured to update from one of these sources, run the following command to list when each package was last updated: $ rpm -qa -last Compare this to Red Hat Security Advisories (RHSA) listed at https://access.redhat.com/security/updates/active/ to determine whether the system is missing applicable security and bugfix updates. If updates are not installed, this is a finding.
53	V-38480	low	Users must be warned 7 days in advance of password expiration.	Setting the password warning age enables users to make the change at a practical time.	None	SV-50280r1_rule	F-43425r1_fix	To specify how many days prior to password expiration that a warning will be issued to users, edit the file "/etc/login.defs" and add or correct the following line, replacing [DAYS] appropriately: PASS_WARN_AGE [DAYS] The DoD requirement is 7.	C-46035r1_chk	To check the password warning age, run the command: $ grep PASS_WARN_AGE /etc/login.defs The DoD requirement is 7. If it is not set to the required value, this is a finding.
54	V-38528	low	The system must log Martian packets.	The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.	None	SV-50329r2_rule	F-43476r1_fix	To set the runtime status of the "net.ipv4.conf.all.log_martians" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.log_martians=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.log_martians = 1	C-46086r3_chk	The status of the "net.ipv4.conf.all.log_martians" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.log_martians The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.all.log_martians /etc/sysctl.conf If the correct value is not returned, this is a finding.
55	V-38529	medium	The system must not accept IPv4 source-routed packets by default.	Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.	None	SV-50330r2_rule	F-43478r1_fix	To set the runtime status of the "net.ipv4.conf.default.accept_source_route" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.accept_source_route=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.default.accept_source_route = 0	C-46088r2_chk	The status of the "net.ipv4.conf.default.accept_source_route" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.accept_source_route The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.default.accept_source_route /etc/sysctl.conf If the correct value is not returned, this is a finding.
56	V-38665	medium	The system package management tool must verify group-ownership on all files and directories associated with the audit package.	Group-ownership of audit binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The group-ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.	None	SV-50466r1_rule	F-43614r1_fix	The RPM package management system can restore file group-ownership of the audit package files and directories. The following command will update audit files with group-ownership different from what is expected by the RPM database: # rpm --setugids audit	C-46225r1_chk	The following command will list which audit files on the system have group-ownership different from what is expected by the RPM database: # rpm -V audit | grep '^......G' If there is output, this is a finding.
57	V-38664	medium	The system package management tool must verify ownership on all files and directories associated with the audit package.	Ownership of audit binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.	None	SV-50465r1_rule	F-43613r1_fix	The RPM package management system can restore file ownership of the audit package files and directories. The following command will update audit files with ownership different from what is expected by the RPM database: # rpm --setugids audit	C-46224r1_chk	The following command will list which audit files on the system have ownership different from what is expected by the RPM database: # rpm -V audit | grep '^.....U' If there is output, this is a finding.
58	V-38667	medium	The system must have a host-based intrusion detection tool installed.	Adding host-based intrusion detection tools can provide the capability to automatically take actions in response to malicious behavior, which can provide additional agility in reacting to network threats. These tools also often include a reporting capability to provide network awareness of system, which may not otherwise exist in an organization's systems management regime.	None	SV-50468r2_rule	F-43616r2_fix	The base Red Hat platform already includes a sophisticated auditing system that can detect intruder activity, as well as SELinux, which provides host-based intrusion prevention capabilities by confining privileged programs and user sessions which may become compromised. In DoD environments, supplemental intrusion detection tools, such as, the McAfee Host-based Security System, are available to integrate with existing infrastructure. When these supplemental tools interfere with the proper functioning of SELinux, SELinux takes precedence.	C-46227r1_chk	Inspect the system to determine if intrusion detection software has been installed. Verify the intrusion detection software is active. If no host-based intrusion detection tools are installed, this is a finding.
59	V-38666	high	The system must use and update a DoD-approved virus scan program.	Virus scanning software can be used to detect if a system has been compromised by computer viruses, as well as to limit their spread to other systems.	None	SV-50467r2_rule	F-43615r2_fix	Install virus scanning software, which uses signatures to search for the presence of viruses on the filesystem. The McAfee VirusScan Enterprise for Linux virus scanning tool is provided for DoD systems. Ensure virus definition files are no older than 7 days, or their last release. Configure the virus scanning software to perform scans dynamically on all accessed files. If this is not possible, configure the system to scan all altered files on the system on a daily basis. If the system processes inbound SMTP mail, configure the virus scanner to scan all received mail.	C-46226r2_chk	Inspect the system for a cron job or system service which executes a virus scanning tool regularly. To verify the McAfee VSEL system service is operational, run the following command: # /etc/init.d/nails status To check on the age of uvscan virus definition files, run the following command: # cd /opt/NAI/LinuxShield/engine/dat # ls -la avvscan.dat avvnames.dat avvclean.dat If virus scanning software does not run continuously, or at least daily, or has signatures that are out of date, this is a finding.
60	V-38661	low	The operating system must protect the confidentiality and integrity of data at rest.	The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.	None	SV-50462r1_rule	F-43610r1_fix	Red Hat Enterprise Linux 6 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time. For manual installations, select the "Encrypt" checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots. For automated/unattended installations, it is possible to use Kickstart by adding the "--encrypted" and "--passphrase=" options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition: part / --fstype=ext3 --size=100 --onpart=hda1 --encrypted --passphrase=[PASSPHRASE] Any [PASSPHRASE] is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the "--passphrase=" option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation. Detailed information on encrypting partitions using LUKS can be found on the Red Had Documentation web site: https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-Security_Guide-LUKS_Disk_Encryption.html	C-46221r1_chk	Determine if encryption must be used to protect data on the system. If encryption must be used and is not employed, this is a finding.
61	V-38660	medium	The snmpd service must use only SNMP protocol version 3 or newer.	Earlier versions of SNMP are considered insecure, as they potentially allow unauthorized access to detailed system management information.	None	SV-50461r1_rule	F-43604r1_fix	Edit "/etc/snmp/snmpd.conf", removing any references to "v1", "v2c", or "com2sec". Upon doing that, restart the SNMP service: # service snmpd restart	C-46215r1_chk	To ensure only SNMPv3 or newer is used, run the following command: # grep 'v1\|v2c\|com2sec' /etc/snmp/snmpd.conf | grep -v '^#' There should be no output. If there is output, this is a finding.
62	V-38663	medium	The system package management tool must verify permissions on all files and directories associated with the audit package.	Permissions on audit binaries and configuration files that are too generous could allow an unauthorized user to gain privileges that they should not have. The permissions set by the vendor should be maintained. Any deviations from this baseline should be investigated.	None	SV-50464r1_rule	F-43612r1_fix	The RPM package management system can restore file access permissions of the audit package files and directories. The following command will update audit files with permissions different from what is expected by the RPM database: # rpm --setperms audit	C-46223r1_chk	The following command will list which audit files on the system have permissions different from what is expected by the RPM database: # rpm -V audit | grep '^.M' If there is any output, for each file or directory found, compare the RPM-expected permissions with the permissions on the file or directory: # rpm -q --queryformat "[%{FILENAMES} %{FILEMODES:perms}\n]" audit | grep [filename] # ls -lL [filename] If the existing permissions are more permissive than those expected by RPM, this is a finding.
63	V-38662	low	The operating system must employ cryptographic mechanisms to prevent unauthorized disclosure of data at rest unless otherwise protected by alternative physical measures.	The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.	None	SV-50463r1_rule	F-43611r1_fix	Red Hat Enterprise Linux 6 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time. For manual installations, select the "Encrypt" checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots. For automated/unattended installations, it is possible to use Kickstart by adding the "--encrypted" and "--passphrase=" options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition: part / --fstype=ext3 --size=100 --onpart=hda1 --encrypted --passphrase=[PASSPHRASE] Any [PASSPHRASE] is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the "--passphrase=" option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation. Detailed information on encrypting partitions using LUKS can be found on the Red Had Documentation web site: https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-Security_Guide-LUKS_Disk_Encryption.html	C-46222r1_chk	Determine if encryption must be used to protect data on the system. If encryption must be used and is not employed, this is a finding.
64	V-38446	medium	The mail system must forward all mail for root to one or more system administrators.	A number of system services utilize email messages sent to the root user to notify system administrators of active or impending issues. These messages must be forwarded to at least one monitored email address.	None	SV-50246r1_rule	F-43391r1_fix	Set up an alias for root that forwards to a monitored email address: # echo "root: <system.administrator>@mail.mil" >> /etc/aliases # newaliases	C-46001r1_chk	Find the list of alias maps used by the Postfix mail server: # postconf alias_maps Query the Postfix alias maps for an alias for "root": # postmap -q root <alias_map> If there are no aliases configured for root that forward to a monitored email address, this is a finding.
65	V-38669	low	The postfix service must be enabled for mail delivery.	Local mail delivery is essential to some system maintenance and notification tasks.	None	SV-50470r1_rule	F-43618r1_fix	The Postfix mail transfer agent is used for local mail delivery within the system. The default configuration only listens for connections to the default SMTP port (port 25) on the loopback interface (127.0.0.1). It is recommended to leave this service enabled for local mail delivery. The "postfix" service can be enabled with the following command: # chkconfig postfix on # service postfix start	C-46230r1_chk	Run the following command to determine the current status of the "postfix" service: # service postfix status If the service is enabled, it should return the following: postfix is running... If the service is not enabled, this is a finding.
66	V-38668	high	The x86 Ctrl-Alt-Delete key sequence must be disabled.	A locally logged-in user who presses Ctrl-Alt-Delete, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In the GNOME graphical environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.	None	SV-50469r2_rule	F-43617r2_fix	By default, the system includes the following line in "/etc/init/control-alt-delete.conf" to reboot the system when the Ctrl-Alt-Delete key sequence is pressed: exec /sbin/shutdown -r now "Ctrl-Alt-Delete pressed" To configure the system to log a message instead of rebooting the system, add the following line to "/etc/init/control-alt-delete.override" to read as follows: exec /usr/bin/logger -p security.info "Ctrl-Alt-Delete pressed"	C-46228r2_chk	To ensure the system is configured to log a message instead of rebooting the system when Ctrl-Alt-Delete is pressed, ensure the following line is in "/etc/init/control-alt-delete.override": exec /usr/bin/logger -p security.info "Control-Alt-Delete pressed" If the system is not configured to block the shutdown command when Ctrl-Alt-Delete is pressed, this is a finding.
67	V-38467	low	The system must use a separate file system for the system audit data path.	Placing "/var/log/audit" in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.	None	SV-50267r1_rule	F-43412r1_fix	Audit logs are stored in the "/var/log/audit" directory. Ensure that it has its own partition or logical volume at installation time, or migrate it later using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.	C-46022r1_chk	Run the following command to determine if "/var/log/audit" is on its own partition or logical volume: $ mount | grep "on /var/log/audit " If "/var/log/audit" has its own partition or volume group, a line will be returned. If no line is returned, this is a finding.
68	V-38466	medium	Library files must be owned by root.	Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership is necessary to protect the integrity of the system.	None	SV-50266r1_rule	F-43411r1_fix	System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default: /lib /lib64 /usr/lib /usr/lib64 If any file in these directories is found to be owned by a user other than root, correct its ownership with the following command: # chown root [FILE]	C-46021r1_chk	System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default: /lib /lib64 /usr/lib /usr/lib64 Kernel modules, which can be added to the kernel during runtime, are stored in "/lib/modules". All files in these directories should not be group-writable or world-writable. To find shared libraries that are not owned by "root", run the following command for each directory [DIR] which contains shared libraries: $ find -L [DIR] \! -user root If any of these files are not owned by root, this is a finding.
69	V-38465	medium	Library files must have mode 0755 or less permissive.	Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Restrictive permissions are necessary to protect the integrity of the system.	None	SV-50265r3_rule	F-43409r2_fix	System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default: /lib /lib64 /usr/lib /usr/lib64 If any file in these directories is found to be group-writable or world-writable, correct its permission with the following command: # chmod go-w [FILE]	C-46019r4_chk	System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default: /lib /lib64 /usr/lib /usr/lib64 Kernel modules, which can be added to the kernel during runtime, are stored in "/lib/modules". All files in these directories should not be group-writable or world-writable. To find shared libraries that are group-writable or world-writable, run the following command for each directory [DIR] which contains shared libraries: $ find -L [DIR] -perm /022 -type f If any of these files (excluding broken symlinks) are group-writable or world-writable, this is a finding.
70	V-38464	medium	The audit system must take appropriate action when there are disk errors on the audit storage volume.	Taking appropriate action in case of disk errors will minimize the possibility of losing audit records.	None	SV-50264r1_rule	F-43410r1_fix	Edit the file "/etc/audit/auditd.conf". Modify the following line, substituting [ACTION] appropriately: disk_error_action = [ACTION] Possible values for [ACTION] are described in the "auditd.conf" man page. These include: "ignore" "syslog" "exec" "suspend" "single" "halt" Set this to "syslog", "exec", "single", or "halt".	C-46020r1_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine if the system is configured to take appropriate action when disk errors occur: # grep disk_error_action /etc/audit/auditd.conf disk_error_action = [ACTION] If the system is configured to "suspend" when disk errors occur or "ignore" them, this is a finding.
71	V-38463	low	The system must use a separate file system for /var/log.	Placing "/var/log" in its own partition enables better separation between log files and other files in "/var/".	None	SV-50263r1_rule	F-43408r1_fix	System logs are stored in the "/var/log" directory. Ensure that it has its own partition or logical volume at installation time, or migrate it using LVM.	C-46018r1_chk	Run the following command to determine if "/var/log" is on its own partition or logical volume: $ mount | grep "on /var/log " If "/var/log" has its own partition or volume group, a line will be returned. If no line is returned, this is a finding.
72	V-38462	high	The RPM package management tool must cryptographically verify the authenticity of all software packages during installation.	Ensuring all packages' cryptographic signatures are valid prior to installation ensures the provenance of the software and protects against malicious tampering.	None	SV-50262r1_rule	F-43407r1_fix	Edit the RPM configuration files containing the "nosignature" option and remove the option.	C-46017r1_chk	Verify RPM signature validation is not disabled: # grep nosignature /etc/rpmrc /usr/lib/rpm/rpmrc /usr/lib/rpm/redhat/rpmrc ~root/.rpmrc If any configuration is found, this is a finding.
73	V-38461	medium	The /etc/group file must have mode 0644 or less permissive.	The "/etc/group" file contains information regarding groups that are configured on the system. Protection of this file is important for system security.	None	SV-50261r1_rule	F-43406r1_fix	To properly set the permissions of "/etc/group", run the command: # chmod 644 /etc/group	C-46015r1_chk	To check the permissions of "/etc/group", run the command: $ ls -l /etc/group If properly configured, the output should indicate the following permissions: "-rw-r--r--" If it does not, this is a finding.
74	V-38460	low	The NFS server must not have the all_squash option enabled.	The "all_squash" option maps all client requests to a single anonymous uid/gid on the NFS server, negating the ability to track file access by user ID.	None	SV-50260r1_rule	F-43405r1_fix	Remove any instances of the "all_squash" option from the file "/etc/exports". Restart the NFS daemon for the changes to take effect. # service nfs restart	C-46016r1_chk	If the NFS server is read-only, in support of unrestricted access to organizational content, this is not applicable. The related "root_squash" option provides protection against remote administrator-level access to NFS server content. Its use is not a finding. To verify the "all_squash" option has been disabled, run the following command: # grep all_squash /etc/exports If there is output, this is a finding.
75	V-38492	medium	The system must prevent the root account from logging in from virtual consoles.	Preventing direct root login to virtual console devices helps ensure accountability for actions taken on the system using the root account.	None	SV-50293r1_rule	F-43439r2_fix	To restrict root logins through the (deprecated) virtual console devices, ensure lines of this form do not appear in "/etc/securetty": vc/1 vc/2 vc/3 vc/4 Note: Virtual console entries are not limited to those listed above. Any lines starting with "vc/" followed by numerals should be removed.	C-46049r1_chk	To check for virtual console entries which permit root login, run the following command: # grep '^vc/[0-9]' /etc/securetty If any output is returned, then root logins over virtual console devices is permitted. If root login over virtual console devices is permitted, this is a finding.
76	V-38702	low	The FTP daemon must be configured for logging or verbose mode.	To trace malicious activity facilitated by the FTP service, it must be configured to ensure that all commands sent to the ftp server are logged using the verbose vsftpd log format. The default vsftpd log file is /var/log/vsftpd.log.	None	SV-50503r1_rule	F-43651r1_fix	Add or correct the following configuration options within the "vsftpd" configuration file, located at "/etc/vsftpd/vsftpd.conf". xferlog_enable=YES xferlog_std_format=NO log_ftp_protocol=YES	C-46264r1_chk	Find if logging is applied to the ftp daemon. Procedures: If vsftpd is started by xinetd the following command will indicate the xinetd.d startup file. # grep vsftpd /etc/xinetd.d/* # grep server_args [vsftpd xinetd.d startup file] This will indicate the vsftpd config file used when starting through xinetd. If the [server_args]line is missing or does not include the vsftpd configuration file, then the default config file (/etc/vsftpd/vsftpd.conf) is used. # grep xferlog_enable [vsftpd config file] If xferlog_enable is missing, or is not set to yes, this is a finding.
77	V-38469	medium	All system command files must have mode 755 or less permissive.	System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.	None	SV-50269r3_rule	F-43414r1_fix	System executables are stored in the following directories by default: /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin If any file in these directories is found to be group-writable or world-writable, correct its permission with the following command: # chmod go-w [FILE]	C-46024r3_chk	System executables are stored in the following directories by default: /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin All files in these directories should not be group-writable or world-writable. To find system executables that are group-writable or world-writable, run the following command for each directory [DIR] which contains system executables: $ find -L [DIR] -perm /022 -type f If any system executables are found to be group-writable or world-writable, this is a finding.
78	V-38468	medium	The audit system must take appropriate action when the audit storage volume is full.	Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.	None	SV-50268r1_rule	F-43413r1_fix	The "auditd" service can be configured to take an action when disk space starts to run low. Edit the file "/etc/audit/auditd.conf". Modify the following line, substituting [ACTION] appropriately: disk_full_action = [ACTION] Possible values for [ACTION] are described in the "auditd.conf" man page. These include: "ignore" "syslog" "exec" "suspend" "single" "halt" Set this to "syslog", "exec", "single", or "halt".	C-46023r1_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine if the system is configured to take appropriate action when the audit storage volume is full: # grep disk_full_action /etc/audit/auditd.conf disk_full_action = [ACTION] If the system is configured to "suspend" when the volume is full or "ignore" that it is full, this is a finding.
79	V-38553	medium	The operating system must prevent public IPv6 access into an organizations internal networks, except as appropriately mediated by managed interfaces employing boundary protection devices.	The "ip6tables" service provides the system's host-based firewalling capability for IPv6 and ICMPv6.	None	SV-50354r3_rule	F-43501r2_fix	The "ip6tables" service can be enabled with the following commands: # chkconfig ip6tables on # service ip6tables start	C-46111r3_chk	If the system is a cross-domain system, this is not applicable. If IPv6 is disabled, this is not applicable. Run the following command to determine the current status of the "ip6tables" service: # service ip6tables status If the service is not running, it should return the following: ip6tables: Firewall is not running. If the service is not running, this is a finding.
80	V-38552	low	The audit system must be configured to audit all discretionary access control permission modifications using fchown.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50353r3_rule	F-43500r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S fchown -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S fchown -F auid=0 -k perm_mod	C-46110r2_chk	To determine if the system is configured to audit calls to the "fchown" system call, run the following command: $ sudo grep -w "fchown" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
81	V-38498	medium	Audit log files must have mode 0640 or less permissive.	If users can write to audit logs, audit trails can be modified or destroyed.	None	SV-50299r1_rule	F-43445r1_fix	Change the mode of the audit log files with the following command: # chmod 0640 [audit_file]	C-46055r1_chk	Run the following command to check the mode of the system audit logs: grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %a:%n Audit logs must be mode 0640 or less permissive. If any are more permissive, this is a finding.
82	V-38550	low	The audit system must be configured to audit all discretionary access control permission modifications using fchmodat.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50351r3_rule	F-43498r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S fchmodat -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S fchmodat -F auid=0 -k perm_mod	C-46108r2_chk	To determine if the system is configured to audit calls to the "fchmodat" system call, run the following command: $ sudo grep -w "fchmodat" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
83	V-38557	low	The audit system must be configured to audit all discretionary access control permission modifications using fsetxattr.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50358r3_rule	F-43505r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S fsetxattr -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S fsetxattr -F auid=0 -k perm_mod	C-46115r2_chk	To determine if the system is configured to audit calls to the "fsetxattr" system call, run the following command: $ sudo grep -w "fsetxattr" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
84	V-38556	low	The audit system must be configured to audit all discretionary access control permission modifications using fremovexattr.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50357r3_rule	F-43504r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S fremovexattr -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S fremovexattr -F auid=0 -k perm_mod	C-46114r2_chk	To determine if the system is configured to audit calls to the "fremovexattr" system call, run the following command: $ sudo grep -w "fremovexattr" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
85	V-38555	medium	The system must employ a local IPv4 firewall.	The "iptables" service provides the system's host-based firewalling capability for IPv4 and ICMP.	None	SV-50356r2_rule	F-43503r2_fix	The "iptables" service can be enabled with the following commands: # chkconfig iptables on # service iptables start	C-46113r2_chk	If the system is a cross-domain system, this is not applicable. Run the following command to determine the current status of the "iptables" service: # service iptables status If the service is not running, it should return the following: iptables: Firewall is not running. If the service is not running, this is a finding.
86	V-38554	low	The audit system must be configured to audit all discretionary access control permission modifications using fchownat.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50355r3_rule	F-43502r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S fchownat -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S fchownat -F auid=0 -k perm_mod	C-46112r2_chk	To determine if the system is configured to audit calls to the "fchownat" system call, run the following command: $ sudo grep -w "fchownat" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
87	V-51875	medium	The operating system, upon successful logon/access, must display to the user the number of unsuccessful logon/access attempts since the last successful logon/access.	Users need to be aware of activity that occurs regarding their account. Providing users with information regarding the number of unsuccessful attempts that were made to login to their account allows the user to determine if any unauthorized activity has occurred and gives them an opportunity to notify administrators.	None	SV-66089r1_rule	F-56701r1_fix	To configure the system to notify users of last logon/access using "pam_lastlog", add the following line immediately after "session required pam_limits.so": session required pam_lastlog.so showfailed	C-54013r1_chk	To ensure that last logon/access notification is configured correctly, run the following command: # grep pam_lastlog.so /etc/pam.d/system-auth The output should show output "showfailed". If that is not the case, this is a finding.
88	V-38493	medium	Audit log directories must have mode 0755 or less permissive.	If users can delete audit logs, audit trails can be modified or destroyed.	None	SV-50294r1_rule	F-43440r1_fix	Change the mode of the audit log directories with the following command: # chmod go-w [audit_directory]	C-46050r1_chk	Run the following command to check the mode of the system audit directories: grep "^log_file" /etc/audit/auditd.conf|sed 's/^[^/]*//; s/[^/]*$//'|xargs stat -c %a:%n Audit directories must be mode 0755 or less permissive. If any are more permissive, this is a finding.
89	V-38559	low	The audit system must be configured to audit all discretionary access control permission modifications using lremovexattr.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50360r3_rule	F-43507r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S lremovexattr -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S lremovexattr -F auid=0 -k perm_mod	C-46117r2_chk	To determine if the system is configured to audit calls to the "lremovexattr" system call, run the following command: $ sudo grep -w "lremovexattr" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
90	V-38558	low	The audit system must be configured to audit all discretionary access control permission modifications using lchown.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50359r3_rule	F-43506r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S lchown -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S lchown -F auid=0 -k perm_mod	C-46116r2_chk	To determine if the system is configured to audit calls to the "lchown" system call, run the following command: $ sudo grep -w "lchown" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
91	V-38496	medium	Default operating system accounts, other than root, must be locked.	Disabling authentication for default system accounts makes it more difficult for attackers to make use of them to compromise a system.	None	SV-50297r3_rule	F-43442r2_fix	Some accounts are not associated with a human user of the system, and exist to perform some administrative function. An attacker should not be able to log into these accounts. Disable logon access to these accounts with the command: # passwd -l [SYSACCT]	C-46052r2_chk	To obtain a listing of all users and the contents of their shadow password field, run the command: $ awk -F: '$1 !~ /^root$/ && $2 !~ /^[!*]/ {print $1 ":" $2}' /etc/shadow Identify the operating system accounts from this listing. These will primarily be the accounts with UID numbers less than 500, other than root. If any default operating system account (other than root) has a valid password hash, this is a finding.
92	V-38497	high	The system must not have accounts configured with blank or null passwords.	If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.	None	SV-50298r2_rule	F-43444r4_fix	If an account is configured for password authentication but does not have an assigned password, it may be possible to log onto the account without authentication. Remove any instances of the "nullok" option in "/etc/pam.d/system-auth" to prevent logons with empty passwords.	C-46054r2_chk	To verify that null passwords cannot be used, run the following command: # grep nullok /etc/pam.d/system-auth If this produces any output, it may be possible to log into accounts with empty passwords. If NULL passwords can be used, this is a finding.
93	V-38494	low	The system must prevent the root account from logging in from serial consoles.	Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.	None	SV-50295r1_rule	F-43441r1_fix	To restrict root logins on serial ports, ensure lines of this form do not appear in "/etc/securetty": ttyS0 ttyS1 Note: Serial port entries are not limited to those listed above. Any lines starting with "ttyS" followed by numerals should be removed	C-46051r1_chk	To check for serial port entries which permit root login, run the following command: # grep '^ttyS[0-9]' /etc/securetty If any output is returned, then root login over serial ports is permitted. If root login over serial ports is permitted, this is a finding.
94	V-38523	medium	The system must not accept IPv4 source-routed packets on any interface.	Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.	None	SV-50324r2_rule	F-43471r1_fix	To set the runtime status of the "net.ipv4.conf.all.accept_source_route" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.accept_source_route=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.accept_source_route = 0	C-46081r3_chk	The status of the "net.ipv4.conf.all.accept_source_route" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.accept_source_route The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.all.accept_source_route /etc/sysctl.conf If the correct value is not returned, this is a finding.
95	V-38672	low	The netconsole service must be disabled unless required.	The "netconsole" service is not necessary unless there is a need to debug kernel panics, which is not common.	None	SV-50473r2_rule	F-43622r2_fix	The "netconsole" service is responsible for loading the netconsole kernel module, which logs kernel printk messages over UDP to a syslog server. This allows debugging of problems where disk logging fails and serial consoles are impractical. The "netconsole" service can be disabled with the following commands: # chkconfig netconsole off # service netconsole stop	C-46233r1_chk	To check that the "netconsole" service is disabled in system boot configuration, run the following command: # chkconfig "netconsole" --list Output should indicate the "netconsole" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "netconsole" --list "netconsole" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "netconsole" is disabled through current runtime configuration: # service netconsole status If the service is disabled the command will return the following output: netconsole is stopped If the service is running, this is a finding.
96	V-38673	medium	The operating system must ensure unauthorized, security-relevant configuration changes detected are tracked.	By default, AIDE does not install itself for periodic execution. Periodically running AIDE may reveal unexpected changes in installed files.	None	SV-50474r2_rule	F-43621r1_fix	AIDE should be executed on a periodic basis to check for changes. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab: 05 4 * * * root /usr/sbin/aide --check AIDE can be executed periodically through other means; this is merely one example.	C-46232r2_chk	To determine that periodic AIDE execution has been scheduled, run the following command: # grep aide /etc/crontab /etc/cron.*/* If there is no output, this is a finding.
97	V-38670	medium	The operating system must detect unauthorized changes to software and information.	By default, AIDE does not install itself for periodic execution. Periodically running AIDE may reveal unexpected changes in installed files.	None	SV-50471r2_rule	F-43619r1_fix	AIDE should be executed on a periodic basis to check for changes. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab: 05 4 * * * root /usr/sbin/aide --check AIDE can be executed periodically through other means; this is merely one example.	C-46229r2_chk	To determine that periodic AIDE execution has been scheduled, run the following command: # grep aide /etc/crontab /etc/cron.*/* If there is no output, this is a finding.
98	V-38671	medium	The sendmail package must be removed.	The sendmail software was not developed with security in mind and its design prevents it from being effectively contained by SELinux. Postfix should be used instead.	None	SV-50472r1_rule	F-43620r1_fix	Sendmail is not the default mail transfer agent and is not installed by default. The "sendmail" package can be removed with the following command: # yum erase sendmail	C-46231r1_chk	Run the following command to determine if the "sendmail" package is installed: # rpm -q sendmail If the package is installed, this is a finding.
99	V-38676	low	The xorg-x11-server-common (X Windows) package must not be installed, unless required.	Unnecessary packages should not be installed to decrease the attack surface of the system.	None	SV-50477r2_rule	F-43625r1_fix	Removing all packages which constitute the X Window System ensures users or malicious software cannot start X. To do so, run the following command: # yum groupremove "X Window System"	C-46236r1_chk	To ensure the X Windows package group is removed, run the following command: $ rpm -qi xorg-x11-server-common The output should be: package xorg-x11-server-common is not installed If it is not, this is a finding.
100	V-38677	high	The NFS server must not have the insecure file locking option enabled.	Allowing insecure file locking could allow for sensitive data to be viewed or edited by an unauthorized user.	None	SV-50478r1_rule	F-43626r1_fix	By default the NFS server requires secure file-lock requests, which require credentials from the client in order to lock a file. Most NFS clients send credentials with file lock requests, however, there are a few clients that do not send credentials when requesting a file-lock, allowing the client to only be able to lock world-readable files. To get around this, the "insecure_locks" option can be used so these clients can access the desired export. This poses a security risk by potentially allowing the client access to data for which it does not have authorization. Remove any instances of the "insecure_locks" option from the file "/etc/exports".	C-46239r1_chk	To verify insecure file locking has been disabled, run the following command: # grep insecure_locks /etc/exports If there is output, this is a finding.
101	V-38674	medium	X Windows must not be enabled unless required.	Unnecessary services should be disabled to decrease the attack surface of the system.	None	SV-50475r1_rule	F-43623r1_fix	Setting the system's runlevel to 3 will prevent automatic startup of the X server. To do so, ensure the following line in "/etc/inittab" features a "3" as shown: id:3:initdefault:	C-46234r1_chk	To verify the default runlevel is 3, run the following command: # grep initdefault /etc/inittab The output should show the following: id:3:initdefault: If it does not, this is a finding.
102	V-38675	low	Process core dumps must be disabled unless needed.	A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.	None	SV-50476r2_rule	F-43624r1_fix	To disable core dumps for all users, add the following line to "/etc/security/limits.conf": * hard core 0	C-46235r2_chk	To verify that core dumps are disabled for all users, run the following command: $ grep core /etc/security/limits.conf /etc/security/limits.d/*.conf The output should be: * hard core 0 If it is not, this is a finding.
103	V-38630	medium	The graphical desktop environment must automatically lock after 15 minutes of inactivity and the system must require user reauthentication to unlock the environment.	Enabling idle activation of the screen saver ensures the screensaver will be activated after the idle delay. Applications requiring continuous, real-time screen display (such as network management products) require the login session does not have administrator rights and the display station is located in a controlled-access area.	None	SV-50431r3_rule	F-43579r1_fix	Run the following command to activate the screensaver in the GNOME desktop after a period of inactivity: # gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type bool \ --set /apps/gnome-screensaver/idle_activation_enabled true	C-46189r3_chk	If the GConf2 package is not installed, this is not applicable. To check the screensaver mandatory use status, run the following command: $ gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/idle_activation_enabled If properly configured, the output should be "true". If it is not, this is a finding.
104	V-38678	medium	The audit system must provide a warning when allocated audit record storage volume reaches a documented percentage of maximum audit record storage capacity.	Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.	None	SV-50479r2_rule	F-43627r2_fix	The "auditd" service can be configured to take an action when disk space starts to run low. Edit the file "/etc/audit/auditd.conf". Modify the following line, substituting [num_megabytes] appropriately: space_left = [num_megabytes] The "num_megabytes" value should be set to a fraction of the total audit storage capacity available that will allow a system administrator to be notified with enough time to respond to the situation causing the capacity issues. This value must also be documented locally.	C-46240r1_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine whether the system is configured to email the administrator when disk space is starting to run low: # grep space_left /etc/audit/auditd.conf space_left = [num_megabytes] If the "num_megabytes" value does not correspond to a documented value for remaining audit partition capacity or if there is no locally documented value for remaining audit partition capacity, this is a finding.
105	V-58901	medium	The sudo command must require authentication.	The "sudo" command allows authorized users to run programs (including shells) as other users, system users, and root. The "/etc/sudoers" file is used to configure authorized "sudo" users as well as the programs they are allowed to run. Some configuration options in the "/etc/sudoers" file allow configured users to run programs without re-authenticating. Use of these configuration options makes it easier for one compromised account to be used to compromise other accounts.	None	SV-73331r1_rule	F-64285r1_fix	Update the "/etc/sudoers" or other sudo configuration files to remove or comment out lines utilizing the "NOPASSWD" and "!authenticate" options. # visudo # visudo -f [other sudo configuration file]	C-59747r1_chk	Verify neither the "NOPASSWD" option nor the "!authenticate" option is configured for use in "/etc/sudoers" and associated files. Note that the "#include" and "#includedir" directives may be used to include configuration data from locations other than the defaults enumerated here. # egrep '^[^#]*NOPASSWD' /etc/sudoers /etc/sudoers.d/* # egrep '^[^#]*!authenticate' /etc/sudoers /etc/sudoers.d/* If the "NOPASSWD" or "!authenticate" options are configured for use in "/etc/sudoers" or associated files, this is a finding.
106	V-38474	low	The system must allow locking of graphical desktop sessions.	The ability to lock graphical desktop sessions manually allows users to easily secure their accounts should they need to depart from their workstations temporarily.	None	SV-50274r2_rule	F-43420r1_fix	Run the following command to set the Gnome desktop keybinding for locking the screen: # gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type string \ --set /apps/gnome_settings_daemon/keybindings/screensaver "<Control><Alt>l" Another keyboard sequence may be substituted for "<Control><Alt>l", which is the default for the Gnome desktop.	C-46030r2_chk	If the GConf2 package is not installed, this is not applicable. Verify the keybindings for the Gnome screensaver: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome_settings_daemon/keybindings/screensaver If no output is visible, this is a finding.
107	V-38475	medium	The system must require passwords to contain a minimum of 14 characters.	Requiring a minimum password length makes password cracking attacks more difficult by ensuring a larger search space. However, any security benefit from an onerous requirement must be carefully weighed against usability problems, support costs, or counterproductive behavior that may result. While it does not negate the password length requirement, it is preferable to migrate from a password-based authentication scheme to a stronger one based on PKI (public key infrastructure).	None	SV-50275r1_rule	F-43419r1_fix	To specify password length requirements for new accounts, edit the file "/etc/login.defs" and add or correct the following lines: PASS_MIN_LEN 14 The DoD requirement is "14". If a program consults "/etc/login.defs" and also another PAM module (such as "pam_cracklib") during a password change operation, then the most restrictive must be satisfied.	C-46029r1_chk	To check the minimum password length, run the command: $ grep PASS_MIN_LEN /etc/login.defs The DoD requirement is "14". If it is not set to the required value, this is a finding.
108	V-38476	high	Vendor-provided cryptographic certificates must be installed to verify the integrity of system software.	The Red Hat GPG keys are necessary to cryptographically verify packages are from Red Hat.	None	SV-50276r3_rule	F-43421r3_fix	To ensure the system can cryptographically verify base software packages come from Red Hat (and to connect to the Red Hat Network to receive them), the Red Hat GPG keys must be installed properly. To install the Red Hat GPG keys, run: # rhn_register If the system is not connected to the Internet or an RHN Satellite, then install the Red Hat GPG keys from trusted media such as the Red Hat installation CD-ROM or DVD. Assuming the disc is mounted in "/media/cdrom", use the following command as the root user to import them into the keyring: # rpm --import /media/cdrom/RPM-GPG-KEY	C-46031r3_chk	To ensure that the GPG keys are installed, run: $ rpm -q gpg-pubkey The command should return the strings below: gpg-pubkey-fd431d51-4ae0493b gpg-pubkey-2fa658e0-45700c69 If the Red Hat GPG Keys are not installed, this is a finding.
109	V-38477	medium	Users must not be able to change passwords more than once every 24 hours.	Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.	None	SV-50277r1_rule	F-43422r1_fix	To specify password minimum age for new accounts, edit the file "/etc/login.defs" and add or correct the following line, replacing [DAYS] appropriately: PASS_MIN_DAYS [DAYS] A value of 1 day is considered sufficient for many environments. The DoD requirement is 1.	C-46032r1_chk	To check the minimum password age, run the command: $ grep PASS_MIN_DAYS /etc/login.defs The DoD requirement is 1. If it is not set to the required value, this is a finding.
110	V-38470	medium	The audit system must alert designated staff members when the audit storage volume approaches capacity.	Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.	None	SV-50270r2_rule	F-43415r2_fix	The "auditd" service can be configured to take an action when disk space starts to run low. Edit the file "/etc/audit/auditd.conf". Modify the following line, substituting [ACTION] appropriately: space_left_action = [ACTION] Possible values for [ACTION] are described in the "auditd.conf" man page. These include: "ignore" "syslog" "email" "exec" "suspend" "single" "halt" Set this to "email" (instead of the default, which is "suspend") as it is more likely to get prompt attention. The "syslog" option is acceptable, provided the local log management infrastructure notifies an appropriate administrator in a timely manner. RHEL-06-000521 ensures that the email generated through the operation "space_left_action" will be sent to an administrator.	C-46025r3_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine if the system is configured to email the administrator when disk space is starting to run low: # grep space_left_action /etc/audit/auditd.conf space_left_action = email If the system is not configured to send an email to the system administrator when disk space is starting to run low, this is a finding. The "syslog" option is acceptable when it can be demonstrated that the local log management infrastructure notifies an appropriate administrator in a timely manner.
111	V-38471	low	The system must forward audit records to the syslog service.	The auditd service does not include the ability to send audit records to a centralized server for management directly. It does, however, include an audit event multiplexor plugin (audispd) to pass audit records to the local syslog server.	None	SV-50271r1_rule	F-43416r1_fix	Set the "active" line in "/etc/audisp/plugins.d/syslog.conf" to "yes". Restart the auditd process. # service auditd restart	C-46026r1_chk	Verify the audispd plugin is active: # grep active /etc/audisp/plugins.d/syslog.conf If the "active" setting is missing or set to "no", this is a finding.
112	V-38679	medium	The DHCP client must be disabled if not needed.	DHCP relies on trusting the local network. If the local network is not trusted, then it should not be used. However, the automatic configuration provided by DHCP is commonly used and the alternative, manual configuration, presents an unacceptable burden in many circumstances.	None	SV-50480r2_rule	F-43628r2_fix	For each interface [IFACE] on the system (e.g. eth0), edit "/etc/sysconfig/network-scripts/ifcfg-[IFACE]" and make the following changes. Correct the BOOTPROTO line to read: BOOTPROTO=none Add or correct the following lines, substituting the appropriate values based on your site's addressing scheme: NETMASK=[local LAN netmask] IPADDR=[assigned IP address] GATEWAY=[local LAN default gateway]	C-46242r2_chk	To verify that DHCP is not being used, examine the following file for each interface. # /etc/sysconfig/network-scripts/ifcfg-[IFACE] If there is any network interface without a associated "ifcfg" file, this is a finding. Look for the following: BOOTPROTO=none Also verify the following, substituting the appropriate values based on your site's addressing scheme: NETMASK=[local LAN netmask] IPADDR=[assigned IP address] GATEWAY=[local LAN default gateway] If it does not, this is a finding.
113	V-38473	low	The system must use a separate file system for user home directories.	Ensuring that "/home" is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.	None	SV-50273r1_rule	F-43418r1_fix	If user home directories will be stored locally, create a separate partition for "/home" at installation time (or migrate it later using LVM). If "/home" will be mounted from another system such as an NFS server, then creating a separate partition is not necessary at installation time, and the mountpoint can instead be configured later.	C-46028r1_chk	Run the following command to determine if "/home" is on its own partition or logical volume: $ mount | grep "on /home " If "/home" has its own partition or volume group, a line will be returned. If no line is returned, this is a finding.
114	V-38536	low	The operating system must automatically audit account disabling actions.	In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.	None	SV-50337r1_rule	F-43484r1_fix	Add the following to "/etc/audit/audit.rules", in order to capture events that modify account changes: # audit_account_changes -w /etc/group -p wa -k audit_account_changes -w /etc/passwd -p wa -k audit_account_changes -w /etc/gshadow -p wa -k audit_account_changes -w /etc/shadow -p wa -k audit_account_changes -w /etc/security/opasswd -p wa -k audit_account_changes	C-46094r1_chk	To determine if the system is configured to audit account changes, run the following command: auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow|/etc/security/opasswd)' If the system is configured to watch for account changes, lines should be returned for each file specified (and with "perm=wa" for each). If the system is not configured to audit account changes, this is a finding.
115	V-38478	low	The Red Hat Network Service (rhnsd) service must not be running, unless using RHN or an RHN Satellite.	Although systems management and patching is extremely important to system security, management by a system outside the enterprise enclave is not desirable for some environments. However, if the system is being managed by RHN or RHN Satellite Server the "rhnsd" daemon can remain on.	None	SV-50278r2_rule	F-43423r2_fix	The Red Hat Network service automatically queries Red Hat Network servers to determine whether there are any actions that should be executed, such as package updates. This only occurs if the system was registered to an RHN server or satellite and managed as such. The "rhnsd" service can be disabled with the following commands: # chkconfig rhnsd off # service rhnsd stop	C-46033r2_chk	If the system uses RHN or an RHN Satellite, this is not applicable. To check that the "rhnsd" service is disabled in system boot configuration, run the following command: # chkconfig "rhnsd" --list Output should indicate the "rhnsd" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "rhnsd" --list "rhnsd" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "rhnsd" is disabled through current runtime configuration: # service rhnsd status If the service is disabled the command will return the following output: rhnsd is stopped If the service is running, this is a finding.
116	V-38479	medium	User passwords must be changed at least every 60 days.	Setting the password maximum age ensures users are required to periodically change their passwords. This could possibly decrease the utility of a stolen password. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.	None	SV-50279r1_rule	F-43424r1_fix	To specify password maximum age for new accounts, edit the file "/etc/login.defs" and add or correct the following line, replacing [DAYS] appropriately: PASS_MAX_DAYS [DAYS] The DoD requirement is 60.	C-46034r1_chk	To check the maximum password age, run the command: $ grep PASS_MAX_DAYS /etc/login.defs The DoD requirement is 60. If it is not set to the required value, this is a finding.
117	V-54381	medium	The audit system must switch the system to single-user mode when available audit storage volume becomes dangerously low.	Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.	None	SV-68627r1_rule	F-59235r2_fix	The "auditd" service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file "/etc/audit/auditd.conf". Add or modify the following line, substituting [ACTION] appropriately: admin_space_left_action = [ACTION] Set this value to "single" to cause the system to switch to single-user mode for corrective action. Acceptable values also include "suspend" and "halt". For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. Details regarding all possible values for [ACTION] are described in the "auditd.conf" man page.	C-54997r2_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine if the system is configured to either suspend, switch to single-user mode, or halt when disk space has run low: admin_space_left_action single If the system is not configured to switch to single-user mode for corrective action, this is a finding.
118	V-38445	medium	Audit log files must be group-owned by root.	If non-privileged users can write to audit logs, audit trails can be modified or destroyed.	None	SV-50245r2_rule	F-43390r1_fix	Change the group owner of the audit log files with the following command: # chgrp root [audit_file]	C-46000r1_chk	Run the following command to check the group owner of the system audit logs: grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %G:%n Audit logs must be group-owned by root. If they are not, this is a finding.
119	V-38540	low	The audit system must be configured to audit modifications to the systems network configuration.	The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.	None	SV-50341r2_rule	F-43488r2_fix	Add the following to "/etc/audit/audit.rules", setting ARCH to either b32 or b64 as appropriate for your system: # audit_network_modifications -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_network_modifications -w /etc/issue -p wa -k audit_network_modifications -w /etc/issue.net -p wa -k audit_network_modifications -w /etc/hosts -p wa -k audit_network_modifications -w /etc/sysconfig/network -p wa -k audit_network_modifications	C-46098r1_chk	To determine if the system is configured to audit changes to its network configuration, run the following command: auditctl -l | egrep '(sethostname|setdomainname|/etc/issue|/etc/issue.net|/etc/hosts|/etc/sysconfig/network)' If the system is configured to watch for network configuration changes, a line should be returned for each file specified (and "perm=wa" should be indicated for each). If the system is not configured to audit changes of the network configuration, this is a finding.
120	V-38541	low	The audit system must be configured to audit modifications to the systems Mandatory Access Control (MAC) configuration (SELinux).	The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.	None	SV-50342r1_rule	F-43489r1_fix	Add the following to "/etc/audit/audit.rules": -w /etc/selinux/ -p wa -k MAC-policy	C-46099r1_chk	To determine if the system is configured to audit changes to its SELinux configuration files, run the following command: # auditctl -l | grep "dir=/etc/selinux" If the system is configured to watch for changes to its SELinux configuration, a line should be returned (including "perm=wa" indicating permissions that are watched). If the system is not configured to audit attempts to change the MAC policy, this is a finding.
121	V-38542	medium	The system must use a reverse-path filter for IPv4 network traffic when possible on all interfaces.	Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.	None	SV-50343r2_rule	F-43490r1_fix	To set the runtime status of the "net.ipv4.conf.all.rp_filter" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.rp_filter=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.rp_filter = 1	C-46100r2_chk	The status of the "net.ipv4.conf.all.rp_filter" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.rp_filter The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.all.rp_filter /etc/sysctl.conf If the correct value is not returned, this is a finding.
122	V-38543	low	The audit system must be configured to audit all discretionary access control permission modifications using chmod.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50344r3_rule	F-43491r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S chmod -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S chmod -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S chmod -F auid=0 -k perm_mod	C-46101r2_chk	To determine if the system is configured to audit calls to the "chmod" system call, run the following command: $ sudo grep -w "chmod" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If the system is not configured to audit permission changes, this is a finding.
123	V-38544	medium	The system must use a reverse-path filter for IPv4 network traffic when possible by default.	Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.	None	SV-50345r2_rule	F-43492r1_fix	To set the runtime status of the "net.ipv4.conf.default.rp_filter" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.rp_filter=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.default.rp_filter = 1	C-46102r2_chk	The status of the "net.ipv4.conf.default.rp_filter" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.rp_filter The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.default.rp_filter /etc/sysctl.conf If the correct value is not returned, this is a finding.
124	V-38491	high	There must be no .rhosts or hosts.equiv files on the system.	Trust files are convenient, but when used in conjunction with the R-services, they can allow unauthenticated access to a system.	None	SV-50292r1_rule	F-43438r1_fix	The files "/etc/hosts.equiv" and "~/.rhosts" (in each user's home directory) list remote hosts and users that are trusted by the local system when using the rshd daemon. To remove these files, run the following command to delete them from any location. # rm /etc/hosts.equiv $ rm ~/.rhosts	C-46048r1_chk	The existence of the file "/etc/hosts.equiv" or a file named ".rhosts" inside a user home directory indicates the presence of an Rsh trust relationship. If these files exist, this is a finding.
125	V-38546	medium	The IPv6 protocol handler must not be bound to the network stack unless needed.	Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.	None	SV-50347r2_rule	F-43494r2_fix	To prevent the IPv6 kernel module ("ipv6") from binding to the IPv6 networking stack, add the following line to "/etc/modprobe.d/disabled.conf" (or another file in "/etc/modprobe.d"): options ipv6 disable=1 This permits the IPv6 module to be loaded (and thus satisfy other modules that depend on it), while disabling support for the IPv6 protocol.	C-46104r2_chk	If the system uses IPv6, this is not applicable. If the system is configured to disable the "ipv6" kernel module, it will contain a line of the form: options ipv6 disable=1 Such lines may be inside any file in "/etc/modprobe.d" or the deprecated "/etc/modprobe.conf". This permits insertion of the IPv6 kernel module (which other parts of the system expect to be present), but otherwise keeps it inactive. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r ipv6 /etc/modprobe.conf /etc/modprobe.d If the IPv6 kernel module is not disabled, this is a finding.
126	V-38547	low	The audit system must be configured to audit all discretionary access control permission modifications using fchmod.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50348r3_rule	F-43495r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S fchmod -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S fchmod -F auid=0 -k perm_mod	C-46105r2_chk	To determine if the system is configured to audit calls to the "fchmod" system call, run the following command: $ sudo grep -w "fchmod" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
127	V-38548	medium	The system must ignore ICMPv6 redirects by default.	An illicit ICMP redirect message could result in a man-in-the-middle attack.	None	SV-50349r3_rule	F-43496r1_fix	To set the runtime status of the "net.ipv6.conf.default.accept_redirects" kernel parameter, run the following command: # sysctl -w net.ipv6.conf.default.accept_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv6.conf.default.accept_redirects = 0	C-46106r3_chk	If IPv6 is disabled, this is not applicable. The status of the "net.ipv6.conf.default.accept_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv6.conf.default.accept_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv6.conf.default.accept_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
128	V-38549	medium	The system must employ a local IPv6 firewall.	The "ip6tables" service provides the system's host-based firewalling capability for IPv6 and ICMPv6.	None	SV-50350r3_rule	F-43497r3_fix	The "ip6tables" service can be enabled with the following commands: # chkconfig ip6tables on # service ip6tables start	C-46107r3_chk	If the system is a cross-domain system, this is not applicable. If IPv6 is disabled, this is not applicable. Run the following command to determine the current status of the "ip6tables" service: # service ip6tables status If the service is not running, it should return the following: ip6tables: Firewall is not running. If the service is not running, this is a finding.
129	V-38482	low	The system must require passwords to contain at least one numeric character.	Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.	None	SV-50282r1_rule	F-43427r1_fix	The pam_cracklib module's "dcredit" parameter controls requirements for usage of digits in a password. When set to a negative number, any password will be required to contain that many digits. When set to a positive number, pam_cracklib will grant +1 additional length credit for each digit. Add "dcredit=-1" after pam_cracklib.so to require use of a digit in passwords.	C-46037r1_chk	To check how many digits are required in a password, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth The "dcredit" parameter (as a negative number) will indicate how many digits are required. The DoD requires at least one digit in a password. This would appear as "dcredit=-1". If dcredit is not found or not set to the required value, this is a finding.
130	V-38454	low	The system package management tool must verify ownership on all files and directories associated with packages.	Ownership of system binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.	None	SV-50254r1_rule	F-43400r1_fix	The RPM package management system can restore ownership of package files and directories. The following command will update files and directories with ownership different from what is expected by the RPM database: # rpm -qf [file or directory name] # rpm --setugids [package]	C-46010r1_chk	The following command will list which files on the system have ownership different from what is expected by the RPM database: # rpm -Va | grep '^.....U' If there is output, this is a finding.
131	V-38472	medium	All system command files must be owned by root.	System binaries are executed by privileged users as well as system services, and restrictive permissions are necessary to ensure that their execution of these programs cannot be co-opted.	None	SV-50272r1_rule	F-43417r1_fix	System executables are stored in the following directories by default: /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin If any file [FILE] in these directories is found to be owned by a user other than root, correct its ownership with the following command: # chown root [FILE]	C-46027r1_chk	System executables are stored in the following directories by default: /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin All files in these directories should not be group-writable or world-writable. To find system executables that are not owned by "root", run the following command for each directory [DIR] which contains system executables: $ find -L [DIR] \! -user root If any system executables are found to not be owned by root, this is a finding.
132	V-38689	medium	The Department of Defense (DoD) login banner must be displayed immediately prior to, or as part of, graphical desktop environment login prompts.	An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.	None	SV-50490r3_rule	F-43638r2_fix	To set the text shown by the GNOME Display Manager in the login screen, run the following command: # gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type string \ --set /apps/gdm/simple-greeter/banner_message_text \ "[DoD required text]" Where the DoD required text is either: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." OR: "I've read & consent to terms in IS user agreem't." When entering a warning banner that spans several lines, remember to begin and end the string with """. This command writes directly to the file "/var/lib/gdm/.gconf/apps/gdm/simple-greeter/%gconf.xml", and this file can later be edited directly if necessary.	C-46252r3_chk	If the GConf2 package is not installed, this is not applicable. To ensure login warning banner text is properly set, run the following: $ gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gdm/simple-greeter/banner_message_text If properly configured, the proper banner text will appear within this schema. The DoD required text is either: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." OR: "I've read & consent to terms in IS user agreem't." If the DoD required banner text is not appear in the schema, this is a finding.
133	V-38688	medium	A login banner must be displayed immediately prior to, or as part of, graphical desktop environment login prompts.	An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.	None	SV-50489r3_rule	F-43637r2_fix	To enable displaying a login warning banner in the GNOME Display Manager's login screen, run the following command: # gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type bool \ --set /apps/gdm/simple-greeter/banner_message_enable true To display a banner, this setting must be enabled and then banner text must also be set.	C-46250r3_chk	If the GConf2 package is not installed, this is not applicable. To ensure a login warning banner is enabled, run the following: $ gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gdm/simple-greeter/banner_message_enable Search for the "banner_message_enable" schema. If properly configured, the "default" value should be "true". If it is not, this is a finding.
134	V-38687	low	The system must provide VPN connectivity for communications over untrusted networks.	Providing the ability for remote users or systems to initiate a secure VPN connection protects information when it is transmitted over a wide area network.	None	SV-50488r2_rule	F-43636r1_fix	The Openswan package provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The "openswan" package can be installed with the following command: # yum install openswan	C-46249r2_chk	If the system does not communicate over untrusted networks, this is not applicable. Run the following command to determine if the "openswan" package is installed: # rpm -q openswan If the package is not installed, this is a finding.
135	V-38686	medium	The systems local firewall must implement a deny-all, allow-by-exception policy for forwarded packets.	In "iptables" the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to "DROP" implements proper design for a firewall, i.e., any packets which are not explicitly permitted should not be accepted.	None	SV-50487r1_rule	F-43635r1_fix	To set the default policy to DROP (instead of ACCEPT) for the built-in FORWARD chain which processes packets that will be forwarded from one interface to another, add or correct the following line in "/etc/sysconfig/iptables": :FORWARD DROP [0:0]	C-46248r1_chk	Run the following command to ensure the default "FORWARD" policy is "DROP": grep ":FORWARD" /etc/sysconfig/iptables The output must be the following: # grep ":FORWARD" /etc/sysconfig/iptables :FORWARD DROP [0:0] If it is not, this is a finding.
136	V-38685	low	Temporary accounts must be provisioned with an expiration date.	When temporary accounts are created, there is a risk they may remain in place and active after the need for them no longer exists. Account expiration greatly reduces the risk of accounts being misused or hijacked.	None	SV-50486r1_rule	F-43634r1_fix	In the event temporary accounts are required, configure the system to terminate them after a documented time period. For every temporary account, run the following command to set an expiration date on it, substituting "[USER]" and "[YYYY-MM-DD]" appropriately: # chage -E [YYYY-MM-DD] [USER] "[YYYY-MM-DD]" indicates the documented expiration date for the account.	C-46247r1_chk	For every temporary account, run the following command to obtain its account aging and expiration information: # chage -l [USER] Verify each of these accounts has an expiration date set as documented. If any temporary accounts have no expiration date set or do not expire within a documented time frame, this is a finding.
137	V-38684	low	The system must limit users to 10 simultaneous system logins, or a site-defined number, in accordance with operational requirements.	Limiting simultaneous user logins can insulate the system from denial of service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions.	None	SV-50485r2_rule	F-43633r1_fix	Limiting the number of allowed users and sessions per user can limit risks related to denial of service attacks. This addresses concurrent sessions for a single account and does not address concurrent sessions by a single user via multiple accounts. To set the number of concurrent sessions per user add the following line in "/etc/security/limits.conf": * hard maxlogins 10 A documented site-defined number may be substituted for 10 in the above.	C-46246r2_chk	Run the following command to ensure the "maxlogins" value is configured for all users on the system: $ grep "maxlogins" /etc/security/limits.conf /etc/security/limits.d/*.conf You should receive output similar to the following: * hard maxlogins 10 If it is not similar, this is a finding.
138	V-38683	low	All accounts on the system must have unique user or account names	Unique usernames allow for accountability on the system.	None	SV-50484r1_rule	F-43632r1_fix	Change usernames, or delete accounts, so each has a unique name.	C-46245r1_chk	Run the following command to check for duplicate account names: # pwck -rq If there are no duplicate names, no line will be returned. If a line is returned, this is a finding.
139	V-38682	medium	The Bluetooth kernel module must be disabled.	If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.	None	SV-50483r3_rule	F-43631r3_fix	The kernel's module loading system can be configured to prevent loading of the Bluetooth module. Add the following to the appropriate "/etc/modprobe.d" configuration file to prevent the loading of the Bluetooth module: install net-pf-31 /bin/true install bluetooth /bin/true	C-46244r3_chk	If the system is configured to prevent the loading of the "bluetooth" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated"/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r bluetooth /etc/modprobe.conf /etc/modprobe.d If the system is configured to prevent the loading of the "net-pf-31" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated"/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r net-pf-31 /etc/modprobe.conf /etc/modprobe.d If no line is returned, this is a finding.
140	V-38681	low	All GIDs referenced in /etc/passwd must be defined in /etc/group	Inconsistency in GIDs between /etc/passwd and /etc/group could lead to a user having unintended rights.	None	SV-50482r2_rule	F-43630r1_fix	Add a group to the system for each GID referenced without a corresponding group.	C-46243r2_chk	To ensure all GIDs referenced in /etc/passwd are defined in /etc/group, run the following command: # pwck -r | grep 'no group' There should be no output. If there is output, this is a finding.
141	V-38680	medium	The audit system must identify staff members to receive notifications of audit log storage volume capacity issues.	Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.	None	SV-50481r1_rule	F-43629r1_fix	The "auditd" service can be configured to send email to a designated account in certain situations. Add or correct the following line in "/etc/audit/auditd.conf" to ensure that administrators are notified via email for those situations: action_mail_acct = root	C-46241r1_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine if the system is configured to send email to an account when it needs to notify an administrator: action_mail_acct = root If auditd is not configured to send emails per identified actions, this is a finding.
142	V-38607	high	The SSH daemon must be configured to use only the SSHv2 protocol.	SSH protocol version 1 suffers from design flaws that result in security vulnerabilities and should not be used.	None	SV-50408r1_rule	F-43555r1_fix	Only SSH protocol version 2 connections should be permitted. The default setting in "/etc/ssh/sshd_config" is correct, and can be verified by ensuring that the following line appears: Protocol 2	C-46165r1_chk	To check which SSH protocol version is allowed, run the following command: # grep Protocol /etc/ssh/sshd_config If configured properly, output should be Protocol 2 If it is not, this is a finding.
143	V-38606	medium	The tftp-server package must not be installed unless required.	Removing the "tftp-server" package decreases the risk of the accidental (or intentional) activation of tftp services.	None	SV-50407r2_rule	F-43554r1_fix	The "tftp-server" package can be removed with the following command: # yum erase tftp-server	C-46164r1_chk	Run the following command to determine if the "tftp-server" package is installed: # rpm -q tftp-server If the package is installed, this is a finding.
144	V-38605	medium	The cron service must be running.	Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.	None	SV-50406r2_rule	F-43553r2_fix	The "crond" service is used to execute commands at preconfigured times. It is required by almost all systems to perform necessary maintenance tasks, such as notifying root of system activity. The "crond" service can be enabled with the following commands: # chkconfig crond on # service crond start	C-46163r1_chk	Run the following command to determine the current status of the "crond" service: # service crond status If the service is enabled, it should return the following: crond is running... If the service is not running, this is a finding.
145	V-38604	medium	The ypbind service must not be running.	Disabling the "ypbind" service ensures the system is not acting as a client in a NIS or NIS+ domain.	None	SV-50405r2_rule	F-43552r2_fix	The "ypbind" service, which allows the system to act as a client in a NIS or NIS+ domain, should be disabled. The "ypbind" service can be disabled with the following commands: # chkconfig ypbind off # service ypbind stop	C-46162r2_chk	To check that the "ypbind" service is disabled in system boot configuration, run the following command: # chkconfig "ypbind" --list Output should indicate the "ypbind" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "ypbind" --list "ypbind" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "ypbind" is disabled through current runtime configuration: # service ypbind status If the service is disabled the command will return the following output: ypbind is stopped If the service is running, this is a finding.
146	V-38603	medium	The ypserv package must not be installed.	Removing the "ypserv" package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.	None	SV-50404r1_rule	F-43551r1_fix	The "ypserv" package can be uninstalled with the following command: # yum erase ypserv	C-46161r1_chk	Run the following command to determine if the "ypserv" package is installed: # rpm -q ypserv If the package is installed, this is a finding.
147	V-38602	high	The rlogind service must not be running.	The rlogin service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.	None	SV-50403r2_rule	F-43549r3_fix	The "rlogin" service, which is available with the "rsh-server" package and runs as a service through xinetd, should be disabled. The "rlogin" service can be disabled with the following command: # chkconfig rlogin off	C-46158r3_chk	To check that the "rlogin" service is disabled in system boot configuration, run the following command: # chkconfig "rlogin" --list Output should indicate the "rlogin" service has either not been installed, or has been disabled, as shown in the example below: # chkconfig "rlogin" --list rlogin off OR error reading information on service rlogin: No such file or directory If the service is running, this is a finding.
148	V-38601	medium	The system must not send ICMPv4 redirects from any interface.	Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.	None	SV-50402r2_rule	F-43548r1_fix	To set the runtime status of the "net.ipv4.conf.all.send_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.send_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.send_redirects = 0	C-46159r2_chk	The status of the "net.ipv4.conf.all.send_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.send_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.all.send_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
149	V-38600	medium	The system must not send ICMPv4 redirects by default.	Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.	None	SV-50401r2_rule	F-43547r1_fix	To set the runtime status of the "net.ipv4.conf.default.send_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.send_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.default.send_redirects = 0	C-46157r2_chk	The status of the "net.ipv4.conf.default.send_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.send_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.default.send_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
150	V-38449	medium	The /etc/gshadow file must have mode 0000.	The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.	None	SV-50249r1_rule	F-43394r1_fix	To properly set the permissions of "/etc/gshadow", run the command: # chmod 0000 /etc/gshadow	C-46004r1_chk	To check the permissions of "/etc/gshadow", run the command: $ ls -l /etc/gshadow If properly configured, the output should indicate the following permissions: "----------" If it does not, this is a finding.
151	V-38448	medium	The /etc/gshadow file must be group-owned by root.	The "/etc/gshadow" file contains group password hashes. Protection of this file is critical for system security.	None	SV-50248r1_rule	F-43393r1_fix	To properly set the group owner of "/etc/gshadow", run the command: # chgrp root /etc/gshadow	C-46003r1_chk	To check the group ownership of "/etc/gshadow", run the command: $ ls -l /etc/gshadow If properly configured, the output should indicate the following group-owner. "root" If it does not, this is a finding.
152	V-38609	medium	The TFTP service must not be running.	Disabling the "tftp" service ensures the system is not acting as a tftp server, which does not provide encryption or authentication.	None	SV-50410r2_rule	F-43557r4_fix	The "tftp" service should be disabled. The "tftp" service can be disabled with the following command: # chkconfig tftp off	C-46166r2_chk	To check that the "tftp" service is disabled in system boot configuration, run the following command: # chkconfig "tftp" --list Output should indicate the "tftp" service has either not been installed, or has been disabled, as shown in the example below: # chkconfig "tftp" --list tftp off OR error reading information on service tftp: No such file or directory If the service is running, this is a finding.
153	V-51391	medium	A file integrity baseline must be created.	For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.	None	SV-65601r1_rule	F-56189r1_fix	Run the following command to generate a new database: # /usr/sbin/aide --init By default, the database will be written to the file "/var/lib/aide/aide.db.new.gz". Storing the database, the configuration file "/etc/aide.conf", and the binary "/usr/sbin/aide" (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity. The newly-generated database can be installed as follows: # cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz To initiate a manual check, run the following command: # /usr/sbin/aide --check If this check produces any unexpected output, investigate.	C-53727r1_chk	To find the location of the AIDE database file, run the following command: # grep DBDIR /etc/aide.conf Using the defined values of the [DBDIR] and [database] variables, verify the existence of the AIDE database file: # ls -l [DBDIR]/[database_file_name] If there is no database file, this is a finding.
154	V-38530	low	The audit system must be configured to audit all attempts to alter system time through /etc/localtime.	Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.	None	SV-50331r1_rule	F-43477r1_fix	Add the following to "/etc/audit/audit.rules": -w /etc/localtime -p wa -k audit_time_rules The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.	C-46087r1_chk	To determine if the system is configured to audit attempts to alter time via the /etc/localtime file, run the following command: # auditctl -l | grep "watch=/etc/localtime" If the system is configured to audit this activity, it will return a line. If the system is not configured to audit time changes, this is a finding.
155	V-38632	medium	The operating system must produce audit records containing sufficient information to establish what type of events occurred.	Ensuring the "auditd" service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.	None	SV-50433r2_rule	F-43581r2_fix	The "auditd" service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The "auditd" service can be enabled with the following commands: # chkconfig auditd on # service auditd start	C-46191r1_chk	Run the following command to determine the current status of the "auditd" service: # service auditd status If the service is enabled, it should return the following: auditd is running... If the service is not running, this is a finding.
156	V-38579	medium	The system boot loader configuration file(s) must be owned by root.	Only root should be able to modify important boot parameters.	None	SV-50380r1_rule	F-43527r1_fix	The file "/etc/grub.conf" should be owned by the "root" user to prevent destruction or modification of the file. To properly set the owner of "/etc/grub.conf", run the command: # chown root /etc/grub.conf	C-46137r1_chk	To check the ownership of "/etc/grub.conf", run the command: $ ls -lL /etc/grub.conf If properly configured, the output should indicate the following owner: "root" If it does not, this is a finding.
157	V-38578	low	The audit system must be configured to audit changes to the /etc/sudoers file.	The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.	None	SV-50379r1_rule	F-43526r1_fix	At a minimum, the audit system should collect administrator actions for all users and root. Add the following to "/etc/audit/audit.rules": -w /etc/sudoers -p wa -k actions	C-46136r1_chk	To verify that auditing is configured for system administrator actions, run the following command: # auditctl -l | grep "watch=/etc/sudoers" If there is no output, this is a finding.
158	V-38613	medium	The system must not permit root logins using remote access programs such as ssh.	Permitting direct root login reduces auditable information about who ran privileged commands on the system and also allows direct attack attempts on root's password.	None	SV-50414r1_rule	F-43561r1_fix	The root user should never be allowed to log in to a system directly over a network. To disable root login via SSH, add or correct the following line in "/etc/ssh/sshd_config": PermitRootLogin no	C-46171r1_chk	To determine how the SSH daemon's "PermitRootLogin" option is set, run the following command: # grep -i PermitRootLogin /etc/ssh/sshd_config If a line indicating "no" is returned, then the required value is set. If the required value is not set, this is a finding.
159	V-38575	low	The audit system must be configured to audit user deletions of files and programs.	Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as detecting malicious processes that attempt to delete log files to conceal their presence.	None	SV-50376r4_rule	F-43523r4_fix	At a minimum, the audit system should collect file deletion events for all users and root. Add the following (or equivalent) to "/etc/audit/audit.rules", setting ARCH to either b32 or b64 as appropriate for your system: -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid=0 -k delete	C-46133r3_chk	To determine if the system is configured to audit calls to the "rmdir" system call, run the following command: $ sudo grep -w "rmdir" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "unlink" system call, run the following command: $ sudo grep -w "unlink" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "unlinkat" system call, run the following command: $ sudo grep -w "unlinkat" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "rename" system call, run the following command: $ sudo grep -w "rename" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "renameat" system call, run the following command: $ sudo grep -w "renameat" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If no line is returned, this is a finding.
160	V-38574	medium	The system must use a FIPS 140-2 approved cryptographic hashing algorithm for generating account password hashes (system-auth).	Using a stronger hashing algorithm makes password cracking attacks more difficult.	None	SV-50375r2_rule	F-43522r2_fix	In "/etc/pam.d/system-auth" and "/etc/pam.d/system-auth-ac", among potentially other files, the "password" section of the files control which PAM modules execute during a password change. Set the "pam_unix.so" module in the "password" section to include the argument "sha512", as shown below: password sufficient pam_unix.so sha512 [other arguments...] This will help ensure when local users change their passwords, hashes for the new passwords will be generated using the SHA-512 algorithm. This is the default. Note that any updates made to "/etc/pam.d/system-auth" will be overwritten by the "authconfig" program. The "authconfig" program should not be used.	C-46132r3_chk	Inspect the "password" section of "/etc/pam.d/system-auth", "/etc/pam.d/system-auth-ac", and other files in "/etc/pam.d" and ensure that the "pam_unix.so" module includes the argument "sha512". $ grep password /etc/pam.d/* | grep pam_unix.so | grep sha512 If it does not, this is a finding.
161	V-38577	medium	The system must use a FIPS 140-2 approved cryptographic hashing algorithm for generating account password hashes (libuser.conf).	Using a stronger hashing algorithm makes password cracking attacks more difficult.	None	SV-50378r1_rule	F-43525r1_fix	In "/etc/libuser.conf", add or correct the following line in its "[defaults]" section to ensure the system will use the SHA-512 algorithm for password hashing: crypt_style = sha512	C-46135r1_chk	Inspect "/etc/libuser.conf" and ensure the following line appears in the "[default]" section: crypt_style = sha512 If it does not, this is a finding.
162	V-38576	medium	The system must use a FIPS 140-2 approved cryptographic hashing algorithm for generating account password hashes (login.defs).	Using a stronger hashing algorithm makes password cracking attacks more difficult.	None	SV-50377r1_rule	F-43524r1_fix	In "/etc/login.defs", add or correct the following line to ensure the system will use SHA-512 as the hashing algorithm: ENCRYPT_METHOD SHA512	C-46134r1_chk	Inspect "/etc/login.defs" and ensure the following line appears: ENCRYPT_METHOD SHA512 If it does not, this is a finding.
163	V-38571	low	The system must require passwords to contain at least one lowercase alphabetic character.	Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.	None	SV-50372r1_rule	F-43519r1_fix	The pam_cracklib module's "lcredit=" parameter controls requirements for usage of lowercase letters in a password. When set to a negative number, any password will be required to contain that many lowercase characters. When set to a positive number, pam_cracklib will grant +1 additional length credit for each lowercase character. Add "lcredit=-1" after pam_cracklib.so to require use of a lowercase character in passwords.	C-46129r1_chk	To check how many lowercase characters are required in a password, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth The "lcredit" parameter (as a negative number) will indicate how many special characters are required. The DoD requires at least one lowercase character in a password. This would appear as "lcredit=-1". If lcredit is not found or not set to the required value, this is a finding.
164	V-38489	medium	A file integrity tool must be installed.	The AIDE package must be installed if it is to be available for integrity checking.	None	SV-50290r1_rule	F-43436r1_fix	Install the AIDE package with the command: # yum install aide	C-46046r1_chk	If another file integrity tool is installed, this is not a finding. Run the following command to determine if the "aide" package is installed: # rpm -q aide If the package is not installed, this is a finding.
165	V-38573	medium	The system must disable accounts after three consecutive unsuccessful logon attempts.	Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks.	None	SV-50374r4_rule	F-43521r8_fix	To configure the system to lock out accounts after a number of incorrect logon attempts using "pam_faillock.so", modify the content of both "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" as follows: Add the following line immediately before the "pam_unix.so" statement in the "AUTH" section: auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately after the "pam_unix.so" statement in the "AUTH" section: auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately before the "pam_unix.so" statement in the "ACCOUNT" section: account required pam_faillock.so Note that any updates made to "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" may be overwritten by the "authconfig" program. The "authconfig" program should not be used.	C-46131r4_chk	To ensure the failed password attempt policy is configured correctly, run the following command: # grep pam_faillock /etc/pam.d/system-auth /etc/pam.d/password-auth The output should show "deny=3" for both files. If that is not the case, this is a finding.
166	V-38572	low	The system must require at least four characters be changed between the old and new passwords during a password change.	Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.	None	SV-50373r1_rule	F-43520r1_fix	The pam_cracklib module's "difok" parameter controls requirements for usage of different characters during a password change. Add "difok=[NUM]" after pam_cracklib.so to require differing characters when changing passwords, substituting [NUM] appropriately. The DoD requirement is 4.	C-46130r1_chk	To check how many characters must differ during a password change, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth The "difok" parameter will indicate how many characters must differ. The DoD requires four characters differ during a password change. This would appear as "difok=4". If difok is not found or not set to the required value, this is a finding.
167	V-38698	medium	The operating system must employ automated mechanisms to detect the presence of unauthorized software on organizational information systems and notify designated organizational officials in accordance with the organization defined frequency.	By default, AIDE does not install itself for periodic execution. Periodically running AIDE may reveal unexpected changes in installed files.	None	SV-50499r2_rule	F-43647r1_fix	AIDE should be executed on a periodic basis to check for changes. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab: 05 4 * * * root /usr/sbin/aide --check AIDE can be executed periodically through other means; this is merely one example.	C-46261r2_chk	To determine that periodic AIDE execution has been scheduled, run the following command: # grep aide /etc/crontab /etc/cron.*/* If there is no output, this is a finding.
168	V-38699	low	All public directories must be owned by a system account.	Allowing a user account to own a world-writable directory is undesirable because it allows the owner of that directory to remove or replace any files that may be placed in the directory by other users.	None	SV-50500r2_rule	F-43648r1_fix	All directories in local partitions which are world-writable should be owned by root or another system account. If any world-writable directories are not owned by a system account, this should be investigated. Following this, the files should be deleted or assigned to an appropriate group.	C-46260r3_chk	The following command will discover and print world-writable directories that are not owned by a system account, given the assumption that only system accounts have a uid lower than 500. Run it once for each local partition [PART]: # find [PART] -xdev -type d -perm -0002 -uid +499 -print If there is output, this is a finding.
169	V-38519	medium	All rsyslog-generated log files must be group-owned by root.	The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.	None	SV-50320r2_rule	F-43466r1_fix	The group-owner of all log files written by "rsyslog" should be root. These log files are determined by the second part of each Rule line in "/etc/rsyslog.conf" and typically all appear in "/var/log". For each log file [LOGFILE] referenced in "/etc/rsyslog.conf", run the following command to inspect the file's group owner: $ ls -l [LOGFILE] If the owner is not "root", run the following command to correct this: # chgrp root [LOGFILE]	C-46076r2_chk	The group-owner of all log files written by "rsyslog" should be root. These log files are determined by the second part of each Rule line in "/etc/rsyslog.conf" and typically all appear in "/var/log". To see the group-owner of a given log file, run the following command: $ ls -l [LOGFILE] Some log files referenced in /etc/rsyslog.conf may be created by other programs and may require exclusion from consideration. If the group-owner is not root, this is a finding.
170	V-38518	medium	All rsyslog-generated log files must be owned by root.	The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.	None	SV-50319r2_rule	F-43465r1_fix	The owner of all log files written by "rsyslog" should be root. These log files are determined by the second part of each Rule line in "/etc/rsyslog.conf" typically all appear in "/var/log". For each log file [LOGFILE] referenced in "/etc/rsyslog.conf", run the following command to inspect the file's owner: $ ls -l [LOGFILE] If the owner is not "root", run the following command to correct this: # chown root [LOGFILE]	C-46075r2_chk	The owner of all log files written by "rsyslog" should be root. These log files are determined by the second part of each Rule line in "/etc/rsyslog.conf" and typically all appear in "/var/log". To see the owner of a given log file, run the following command: $ ls -l [LOGFILE] Some log files referenced in /etc/rsyslog.conf may be created by other programs and may require exclusion from consideration. If the owner is not root, this is a finding.
171	V-38517	medium	The Transparent Inter-Process Communication (TIPC) protocol must be disabled unless required.	Disabling TIPC protects the system against exploitation of any flaws in its implementation.	None	SV-50318r3_rule	F-43464r3_fix	The Transparent Inter-Process Communication (TIPC) protocol is designed to provide communications between nodes in a cluster. To configure the system to prevent the "tipc" kernel module from being loaded, add the following line to a file in the directory "/etc/modprobe.d": install tipc /bin/true	C-46074r3_chk	If the system is configured to prevent the loading of the "tipc" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated"/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r tipc /etc/modprobe.conf /etc/modprobe.d If no line is returned, this is a finding.
172	V-38516	low	The Reliable Datagram Sockets (RDS) protocol must be disabled unless required.	Disabling RDS protects the system against exploitation of any flaws in its implementation.	None	SV-50317r3_rule	F-43463r4_fix	The Reliable Datagram Sockets (RDS) protocol is a transport layer protocol designed to provide reliable high-bandwidth, low-latency communications between nodes in a cluster. To configure the system to prevent the "rds" kernel module from being loaded, add the following line to a file in the directory "/etc/modprobe.d": install rds /bin/true	C-46073r3_chk	If the system is configured to prevent the loading of the "rds" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated "/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r rds /etc/modprobe.conf /etc/modprobe.d If no line is returned, this is a finding.
173	V-38515	medium	The Stream Control Transmission Protocol (SCTP) must be disabled unless required.	Disabling SCTP protects the system against exploitation of any flaws in its implementation.	None	SV-50316r3_rule	F-43462r3_fix	The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with several streams of messages within one connection. To configure the system to prevent the "sctp" kernel module from being loaded, add the following line to a file in the directory "/etc/modprobe.d": install sctp /bin/true	C-46072r3_chk	If the system is configured to prevent the loading of the "sctp" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated"/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r sctp /etc/modprobe.conf /etc/modprobe.d If no line is returned, this is a finding.
174	V-38514	medium	The Datagram Congestion Control Protocol (DCCP) must be disabled unless required.	Disabling DCCP protects the system against exploitation of any flaws in its implementation.	None	SV-50315r3_rule	F-43461r3_fix	The Datagram Congestion Control Protocol (DCCP) is a relatively new transport layer protocol, designed to support streaming media and telephony. To configure the system to prevent the "dccp" kernel module from being loaded, add the following line to a file in the directory "/etc/modprobe.d": install dccp /bin/true	C-46071r3_chk	If the system is configured to prevent the loading of the "dccp" kernel module, it will contain lines inside any file in "/etc/modprobe.d" or the deprecated"/etc/modprobe.conf". These lines instruct the module loading system to run another program (such as "/bin/true") upon a module "install" event. Run the following command to search for such lines in all files in "/etc/modprobe.d" and the deprecated "/etc/modprobe.conf": $ grep -r dccp /etc/modprobe.conf /etc/modprobe.d If no line is returned, this is a finding.
175	V-38690	low	Emergency accounts must be provisioned with an expiration date.	When emergency accounts are created, there is a risk they may remain in place and active after the need for them no longer exists. Account expiration greatly reduces the risk of accounts being misused or hijacked.	None	SV-50491r1_rule	F-43639r1_fix	In the event emergency accounts are required, configure the system to terminate them after a documented time period. For every emergency account, run the following command to set an expiration date on it, substituting "[USER]" and "[YYYY-MM-DD]" appropriately: # chage -E [YYYY-MM-DD] [USER] "[YYYY-MM-DD]" indicates the documented expiration date for the account.	C-46251r1_chk	For every emergency account, run the following command to obtain its account aging and expiration information: # chage -l [USER] Verify each of these accounts has an expiration date set as documented. If any emergency accounts have no expiration date set or do not expire within a documented time frame, this is a finding.
176	V-38691	medium	The Bluetooth service must be disabled.	Disabling the "bluetooth" service prevents the system from attempting connections to Bluetooth devices, which entails some security risk. Nevertheless, variation in this risk decision may be expected due to the utility of Bluetooth connectivity and its limited range.	None	SV-50492r2_rule	F-43640r1_fix	The "bluetooth" service can be disabled with the following command: # chkconfig bluetooth off # service bluetooth stop	C-46253r3_chk	To check that the "bluetooth" service is disabled in system boot configuration, run the following command: # chkconfig "bluetooth" --list Output should indicate the "bluetooth" service has either not been installed or has been disabled at all runlevels, as shown in the example below: # chkconfig "bluetooth" --list "bluetooth" 0:off 1:off 2:off 3:off 4:off 5:off 6:off If the service is configured to run, this is a finding.
177	V-38511	medium	IP forwarding for IPv4 must not be enabled, unless the system is a router.	IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.	None	SV-50312r2_rule	F-43458r2_fix	To set the runtime status of the "net.ipv4.ip_forward" kernel parameter, run the following command: # sysctl -w net.ipv4.ip_forward=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.ip_forward = 0	C-46068r3_chk	The status of the "net.ipv4.ip_forward" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.ip_forward The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.ip_forward /etc/sysctl.conf The ability to forward packets is only appropriate for routers. If the correct value is not returned, this is a finding.
178	V-38693	low	The system must require passwords to contain no more than three consecutive repeating characters.	Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.	None	SV-50494r2_rule	F-43642r2_fix	The pam_cracklib module's "maxrepeat" parameter controls requirements for consecutive repeating characters. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters. Add "maxrepeat=3" after pam_cracklib.so to prevent a run of (3 + 1) or more identical characters. password required pam_cracklib.so maxrepeat=3	C-46255r1_chk	To check the maximum value for consecutive repeating characters, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth Look for the value of the "maxrepeat" parameter. The DoD requirement is 3. If maxrepeat is not found or not set to the required value, this is a finding.
179	V-38597	medium	The system must limit the ability of processes to have simultaneous write and execute access to memory.	ExecShield uses the segmentation feature on all x86 systems to prevent execution in memory higher than a certain address. It writes an address as a limit in the code segment descriptor, to control where code can be executed, on a per-process basis. When the kernel places a process's memory regions such as the stack and heap higher than this address, the hardware prevents execution in that address range.	None	SV-50398r2_rule	F-43545r1_fix	To set the runtime status of the "kernel.exec-shield" kernel parameter, run the following command: # sysctl -w kernel.exec-shield=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": kernel.exec-shield = 1	C-46155r3_chk	The status of the "kernel.exec-shield" kernel parameter can be queried by running the following command: $ sysctl kernel.exec-shield $ grep kernel.exec-shield /etc/sysctl.conf The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". If the correct value is not returned, this is a finding.
180	V-38596	medium	The system must implement virtual address space randomization.	Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code he or she has introduced into a process's address space during an attempt at exploitation. Additionally, ASLR also makes it more difficult for an attacker to know the location of existing code in order to repurpose it using return oriented programming (ROP) techniques.	None	SV-50397r2_rule	F-43543r1_fix	To set the runtime status of the "kernel.randomize_va_space" kernel parameter, run the following command: # sysctl -w kernel.randomize_va_space=2 If this is not the system's default value, add the following line to "/etc/sysctl.conf": kernel.randomize_va_space = 2	C-46153r2_chk	The status of the "kernel.randomize_va_space" kernel parameter can be queried by running the following commands: $ sysctl kernel.randomize_va_space $ grep kernel.randomize_va_space /etc/sysctl.conf The output of the command should indicate a value of at least "1" (preferably "2"). If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". If the correct value is not returned, this is a finding.
181	V-38595	medium	The system must be configured to require the use of a CAC, PIV compliant hardware token, or Alternate Logon Token (ALT) for authentication.	Smart card login provides two-factor authentication stronger than that provided by a username/password combination. Smart cards leverage a PKI (public key infrastructure) in order to provide and verify credentials.	None	SV-50396r2_rule	F-43544r2_fix	To enable smart card authentication, consult the documentation at: https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Managing_Smart_Cards/enabling-smart-card-login.html For guidance on enabling SSH to authenticate against a Common Access Card (CAC), consult documentation at: https://access.redhat.com/solutions/82273	C-46154r1_chk	Interview the SA to determine if all accounts not exempted by policy are using CAC authentication. For DoD systems, the following systems and accounts are exempt from using smart card (CAC) authentication: SIPRNET systems Standalone systems Application accounts Temporary employee accounts, such as students or interns, who cannot easily receive a CAC or PIV Operational tactical locations that are not collocated with RAPIDS workstations to issue CAC or ALT Test systems, such as those with an Interim Approval to Test (IATT) and use a separate VPN, firewall, or security measure preventing access to network and system components from outside the protection boundary documented in the IATT. If non-exempt accounts are not using CAC authentication, this is a finding.
182	V-38594	high	The rshd service must not be running.	The rsh service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.	None	SV-50395r2_rule	F-43542r3_fix	The "rsh" service, which is available with the "rsh-server" package and runs as a service through xinetd, should be disabled. The "rsh" service can be disabled with the following command: # chkconfig rsh off	C-46152r2_chk	To check that the "rsh" service is disabled in system boot configuration, run the following command: # chkconfig "rsh" --list Output should indicate the "rsh" service has either not been installed, or has been disabled, as shown in the example below: # chkconfig "rsh" --list rsh off OR error reading information on service rsh: No such file or directory If the service is running, this is a finding.
183	V-38593	medium	The Department of Defense (DoD) login banner must be displayed immediately prior to, or as part of, console login prompts.	An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.	None	SV-50394r1_rule	F-43540r1_fix	To configure the system login banner: Edit "/etc/issue". Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." OR: "I've read & consent to terms in IS user agreem't."	C-46150r1_chk	To check if the system login banner is compliant, run the following command: $ cat /etc/issue If it does not display the required banner, this is a finding.
184	V-38592	medium	The system must require administrator action to unlock an account locked by excessive failed login attempts.	Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks. Ensuring that an administrator is involved in unlocking locked accounts draws appropriate attention to such situations.	None	SV-50393r4_rule	F-43541r6_fix	To configure the system to lock out accounts after a number of incorrect logon attempts and require an administrator to unlock the account using "pam_faillock.so", modify the content of both "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" as follows: Add the following line immediately before the "pam_unix.so" statement in the "AUTH" section: auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately after the "pam_unix.so" statement in the "AUTH" section: auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately before the "pam_unix.so" statement in the "ACCOUNT" section: account required pam_faillock.so Note that any updates made to "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" may be overwritten by the "authconfig" program. The "authconfig" program should not be used.	C-46151r5_chk	To ensure the failed password attempt policy is configured correctly, run the following command: # grep pam_faillock /etc/pam.d/system-auth /etc/pam.d/password-auth The output should show "unlock_time=<some-large-number>"; the largest acceptable value is 604800 seconds (one week). If that is not the case, this is a finding.
185	V-38591	high	The rsh-server package must not be installed.	The "rsh-server" package provides several obsolete and insecure network services. Removing it decreases the risk of those services' accidental (or intentional) activation.	None	SV-50392r1_rule	F-43539r1_fix	The "rsh-server" package can be uninstalled with the following command: # yum erase rsh-server	C-46149r1_chk	Run the following command to determine if the "rsh-server" package is installed: # rpm -q rsh-server If the package is installed, this is a finding.
186	V-38590	low	The system must allow locking of the console screen in text mode.	Installing "screen" ensures a console locking capability is available for users who may need to suspend console logins.	None	SV-50391r1_rule	F-43538r1_fix	To enable console screen locking when in text mode, install the "screen" package: # yum install screen Instruct users to begin new terminal sessions with the following command: $ screen The console can now be locked with the following key combination: ctrl+a x	C-46148r1_chk	Run the following command to determine if the "screen" package is installed: # rpm -q screen If the package is not installed, this is a finding.
187	V-38456	low	The system must use a separate file system for /var.	Ensuring that "/var" is mounted on its own partition enables the setting of more restrictive mount options. This helps protect system services such as daemons or other programs which use it. It is not uncommon for the "/var" directory to contain world-writable directories, installed by other software packages.	None	SV-50256r1_rule	F-43401r2_fix	The "/var" directory is used by daemons and other system services to store frequently-changing data. Ensure that "/var" has its own partition or logical volume at installation time, or migrate it using LVM.	C-46011r2_chk	Run the following command to determine if "/var" is on its own partition or logical volume: $ mount | grep "on /var " If "/var" has its own partition or volume group, a line will be returned. If no line is returned, this is a finding.
188	V-38457	medium	The /etc/passwd file must have mode 0644 or less permissive.	If the "/etc/passwd" file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.	None	SV-50257r1_rule	F-43397r1_fix	To properly set the permissions of "/etc/passwd", run the command: # chmod 0644 /etc/passwd	C-46007r1_chk	To check the permissions of "/etc/passwd", run the command: $ ls -l /etc/passwd If properly configured, the output should indicate the following permissions: "-rw-r--r--" If it does not, this is a finding.
189	V-38495	medium	Audit log files must be owned by root.	If non-privileged users can write to audit logs, audit trails can be modified or destroyed.	None	SV-50296r1_rule	F-43443r1_fix	Change the owner of the audit log files with the following command: # chown root [audit_file]	C-46053r1_chk	Run the following command to check the owner of the system audit logs: grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %U:%n Audit logs must be owned by root. If they are not, this is a finding.
190	V-38455	low	The system must use a separate file system for /tmp.	The "/tmp" partition is used as temporary storage by many programs. Placing "/tmp" in its own partition enables the setting of more restrictive mount options, which can help protect programs which use it.	None	SV-50255r1_rule	F-43387r1_fix	The "/tmp" directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.	C-45997r1_chk	Run the following command to determine if "/tmp" is on its own partition or logical volume: $ mount | grep "on /tmp " If "/tmp" has its own partition or volume group, a line will be returned. If no line is returned, this is a finding.
191	V-38618	low	The avahi service must be disabled.	Because the Avahi daemon service keeps an open network port, it is subject to network attacks. Its functionality is convenient but is only appropriate if the local network can be trusted.	None	SV-50419r2_rule	F-43567r2_fix	The "avahi-daemon" service can be disabled with the following commands: # chkconfig avahi-daemon off # service avahi-daemon stop	C-46177r1_chk	To check that the "avahi-daemon" service is disabled in system boot configuration, run the following command: # chkconfig "avahi-daemon" --list Output should indicate the "avahi-daemon" service has either not been installed, or has been disabled at all runlevels, as shown in the example below: # chkconfig "avahi-daemon" --list "avahi-daemon" 0:off 1:off 2:off 3:off 4:off 5:off 6:off Run the following command to verify "avahi-daemon" is disabled through current runtime configuration: # service avahi-daemon status If the service is disabled the command will return the following output: avahi-daemon is stopped If the service is running, this is a finding.
192	V-38619	medium	There must be no .netrc files on the system.	Unencrypted passwords for remote FTP servers may be stored in ".netrc" files. DoD policy requires passwords be encrypted in storage and not used in access scripts.	None	SV-50420r2_rule	F-43569r2_fix	The ".netrc" files contain logon information used to auto-logon into FTP servers and reside in the user's home directory. These files may contain unencrypted passwords to remote FTP servers making them susceptible to access by unauthorized users and should not be used. Any ".netrc" files should be removed.	C-46179r3_chk	To check the system for the existence of any ".netrc" files, run the following command: $ sudo find /root /home -xdev -name .netrc If any .netrc files exist, this is a finding.
193	V-38599	medium	The FTPS/FTP service on the system must be configured with the Department of Defense (DoD) login banner.	This setting will cause the system greeting banner to be used for FTP connections as well.	None	SV-50400r2_rule	F-43564r3_fix	Edit the vsftpd configuration file, which resides at "/etc/vsftpd/vsftpd.conf" by default. Add or correct the following configuration options. banner_file=/etc/issue Restart the vsftpd daemon. # service vsftpd restart	C-46174r1_chk	To verify this configuration, run the following command: grep "banner_file" /etc/vsftpd/vsftpd.conf The output should show the value of "banner_file" is set to "/etc/issue", an example of which is shown below. # grep "banner_file" /etc/vsftpd/vsftpd.conf banner_file=/etc/issue If it does not, this is a finding.
194	V-38598	high	The rexecd service must not be running.	The rexec service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.	None	SV-50399r2_rule	F-43546r3_fix	The "rexec" service, which is available with the "rsh-server" package and runs as a service through xinetd, should be disabled. The "rexec" service can be disabled with the following command: # chkconfig rexec off	C-46156r3_chk	To check that the "rexec" service is disabled in system boot configuration, run the following command: # chkconfig "rexec" --list Output should indicate the "rexec" service has either not been installed, or has been disabled, as shown in the example below: # chkconfig "rexec" --list rexec off OR error reading information on service rexec: No such file or directory If the service is running, this is a finding.
195	V-51337	medium	The system must use a Linux Security Module at boot time.	Disabling a major host protection feature, such as SELinux, at boot time prevents it from confining system services at boot time. Further, it increases the chances that it will remain off during system operation.	None	SV-65547r1_rule	F-56147r1_fix	SELinux can be disabled at boot time by an argument in "/etc/grub.conf". Remove any instances of "selinux=0" from the kernel arguments in that file to prevent SELinux from being disabled at boot.	C-54007r1_chk	Inspect "/etc/grub.conf" for any instances of "selinux=0" in the kernel boot arguments. Presence of "selinux=0" indicates that SELinux is disabled at boot time. If SELinux is disabled at boot time, this is a finding.
196	V-38585	medium	The system boot loader must require authentication.	Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.	None	SV-50386r2_rule	F-43533r1_fix	The grub boot loader should have password protection enabled to protect boot-time settings. To do so, select a password and then generate a hash from it by running the following command: # grub-crypt --sha-512 When prompted to enter a password, insert the following line into "/etc/grub.conf" immediately after the header comments. (Use the output from "grub-crypt" as the value of [password-hash]): password --encrypted [password-hash]	C-46143r2_chk	To verify the boot loader password has been set and encrypted, run the following command: # grep password /etc/grub.conf The output should show the following: password --encrypted $6$[rest-of-the-password-hash] If it does not, this is a finding.
197	V-43150	medium	The login user list must be disabled.	Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to quickly enumerate known user accounts without logging in.	None	SV-55880r2_rule	F-48722r2_fix	In the default graphical environment, users logging directly into the system are greeted with a login screen that displays all known users. This functionality should be disabled. Run the following command to disable the user list: $ sudo gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type bool --set /apps/gdm/simple-greeter/disable_user_list true	C-49197r4_chk	If the GConf2 package is not installed, this is not applicable. To ensure the user list is disabled, run the following command: $ gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --get /apps/gdm/simple-greeter/disable_user_list The output should be "true". If it is not, this is a finding.
198	V-38570	low	The system must require passwords to contain at least one special character.	Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.	None	SV-50371r1_rule	F-43518r1_fix	The pam_cracklib module's "ocredit=" parameter controls requirements for usage of special (or ``other'') characters in a password. When set to a negative number, any password will be required to contain that many special characters. When set to a positive number, pam_cracklib will grant +1 additional length credit for each special character. Add "ocredit=-1" after pam_cracklib.so to require use of a special character in passwords.	C-46128r1_chk	To check how many special characters are required in a password, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth The "ocredit" parameter (as a negative number) will indicate how many special characters are required. The DoD requires at least one special character in a password. This would appear as "ocredit=-1". If ocredit is not found or not set to the required value, this is a finding.
199	V-38568	low	The audit system must be configured to audit successful file system mounts.	The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.	None	SV-50369r3_rule	F-43516r2_fix	At a minimum, the audit system should collect media exportation events for all users and root. Add the following to "/etc/audit/audit.rules", setting ARCH to either b32 or b64 as appropriate for your system: -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export -a always,exit -F arch=ARCH -S mount -F auid=0 -k export	C-46126r2_chk	To verify that auditing is configured for all media exportation events, run the following command: $ sudo grep -w "mount" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
200	V-38569	low	The system must require passwords to contain at least one uppercase alphabetic character.	Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.	None	SV-50370r1_rule	F-43517r1_fix	The pam_cracklib module's "ucredit=" parameter controls requirements for usage of uppercase letters in a password. When set to a negative number, any password will be required to contain that many uppercase characters. When set to a positive number, pam_cracklib will grant +1 additional length credit for each uppercase character. Add "ucredit=-1" after pam_cracklib.so to require use of an uppercase character in passwords.	C-46127r1_chk	To check how many uppercase characters are required in a password, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth The "ucredit" parameter (as a negative number) will indicate how many uppercase characters are required. The DoD requires at least one uppercase character in a password. This would appear as "ucredit=-1". If ucredit is not found or not set to the required value, this is a finding.
201	V-57569	medium	The noexec option must be added to the /tmp partition.	Allowing users to execute binaries from world-writable directories such as "/tmp" should never be necessary in normal operation and can expose the system to potential compromise.	None	SV-71919r1_rule	F-62639r1_fix	The "noexec" mount option can be used to prevent binaries from being executed out of "/tmp". Add the "noexec" option to the fourth column of "/etc/fstab" for the line which controls mounting of "/tmp".	C-58279r1_chk	To verify that binaries cannot be directly executed from the /tmp directory, run the following command: $ grep '\s/tmp' /etc/fstab The resulting output will show whether the /tmp partition has the "noexec" flag set. If the /tmp partition does not have the noexec flag set, this is a finding.
202	V-38560	medium	The operating system must connect to external networks or information systems only through managed IPv4 interfaces consisting of boundary protection devices arranged in accordance with an organizational security architecture.	The "iptables" service provides the system's host-based firewalling capability for IPv4 and ICMP.	None	SV-50361r2_rule	F-43508r2_fix	The "iptables" service can be enabled with the following commands: # chkconfig iptables on # service iptables start	C-46118r2_chk	If the system is a cross-domain system, this is not applicable. Run the following command to determine the current status of the "iptables" service: # service iptables status If the service is not running, it should return the following: iptables: Firewall is not running. If the service is not running, this is a finding.
203	V-38561	low	The audit system must be configured to audit all discretionary access control permission modifications using lsetxattr.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50362r3_rule	F-43509r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S lsetxattr -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S lsetxattr -F auid=0 -k perm_mod	C-46119r2_chk	To determine if the system is configured to audit calls to the "lsetxattr" system call, run the following command: $ sudo grep -w "lsetxattr" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
204	V-38566	low	The audit system must be configured to audit failed attempts to access files and programs.	Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.	None	SV-50367r2_rule	F-43514r2_fix	At a minimum, the audit system should collect unauthorized file accesses for all users and root. Add the following to "/etc/audit/audit.rules", setting ARCH to either b32 or b64 as appropriate for your system: -a always,exit -F arch=ARCH -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=ARCH -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=ARCH -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid=0 -k access -a always,exit -F arch=ARCH -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid=0 -k access	C-46124r1_chk	To verify that the audit system collects unauthorized file accesses, run the following commands: # grep EACCES /etc/audit/audit.rules # grep EPERM /etc/audit/audit.rules If either command lacks output, this is a finding.
205	V-38567	low	The audit system must be configured to audit all use of setuid and setgid programs.	Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.	None	SV-50368r4_rule	F-43515r6_fix	At a minimum, the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition [PART]: $ sudo find [PART] -xdev -type f -perm /6000 2>/dev/null Then, for each setuid / setgid program on the system, add a line of the following form to "/etc/audit/audit.rules", where [SETUID_PROG_PATH] is the full path to each setuid / setgid program in the list: -a always,exit -F path=[SETUID_PROG_PATH] -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged	C-46125r7_chk	To verify that auditing of privileged command use is configured, run the following command once for each local partition [PART] to find relevant setuid / setgid programs: $ sudo find [PART] -xdev -type f -perm /6000 2>/dev/null Run the following command to verify entries in the audit rules for all programs found with the previous command: $ sudo grep path /etc/audit/audit.rules It should be the case that all relevant setuid / setgid programs have a line in the audit rules. If that is not the case, this is a finding.
206	V-38565	low	The audit system must be configured to audit all discretionary access control permission modifications using setxattr.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50366r3_rule	F-43513r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S setxattr -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S setxattr -F auid=0 -k perm_mod	C-46123r2_chk	To determine if the system is configured to audit calls to the "setxattr" system call, run the following command: $ sudo grep -w "setxattr" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
207	V-38537	low	The system must ignore ICMPv4 bogus error responses.	Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.	None	SV-50338r2_rule	F-43485r1_fix	To set the runtime status of the "net.ipv4.icmp_ignore_bogus_error_responses" kernel parameter, run the following command: # sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.icmp_ignore_bogus_error_responses = 1	C-46095r2_chk	The status of the "net.ipv4.icmp_ignore_bogus_error_responses" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.icmp_ignore_bogus_error_responses The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.icmp_ignore_bogus_error_responses /etc/sysctl.conf If the correct value is not returned, this is a finding.
208	V-38444	medium	The systems local IPv6 firewall must implement a deny-all, allow-by-exception policy for inbound packets.	In "ip6tables" the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to "DROP" implements proper design for a firewall, i.e., any packets which are not explicitly permitted should not be accepted.	None	SV-50244r2_rule	F-43389r3_fix	To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in "/etc/sysconfig/ip6tables": :INPUT DROP [0:0] Restart the IPv6 firewall: # service ip6tables restart	C-45999r2_chk	If IPv6 is disabled, this is not applicable. Inspect the file "/etc/sysconfig/ip6tables" to determine the default policy for the INPUT chain. It should be set to DROP: # grep ":INPUT" /etc/sysconfig/ip6tables If the default policy for the INPUT chain is not set to DROP, this is a finding.
209	V-38504	medium	The /etc/shadow file must have mode 0000.	The "/etc/shadow" file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.	None	SV-50305r1_rule	F-43451r1_fix	To properly set the permissions of "/etc/shadow", run the command: # chmod 0000 /etc/shadow	C-46061r2_chk	To check the permissions of "/etc/shadow", run the command: $ ls -l /etc/shadow If properly configured, the output should indicate the following permissions: "----------" If it does not, this is a finding.
210	V-38583	medium	The system boot loader configuration file(s) must have mode 0600 or less permissive.	Proper permissions ensure that only the root user can modify important boot parameters.	None	SV-50384r2_rule	F-43531r2_fix	File permissions for "/boot/grub/grub.conf" should be set to 600, which is the default. To properly set the permissions of "/boot/grub/grub.conf", run the command: # chmod 600 /boot/grub/grub.conf Boot partitions based on VFAT, NTFS, or other non-standard configurations may require alternative measures.	C-46141r2_chk	To check the permissions of /etc/grub.conf, run the command: $ sudo ls -lL /etc/grub.conf If properly configured, the output should indicate the following permissions: "-rw-------" If it does not, this is a finding.
211	V-38500	medium	The root account must be the only account having a UID of 0.	An account has root authority if it has a UID of 0. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.	None	SV-50301r2_rule	F-43447r1_fix	If any account other than root has a UID of 0, this misconfiguration should be investigated and the accounts other than root should be removed or have their UID changed.	C-46057r2_chk	To list all password file entries for accounts with UID 0, run the following command: # awk -F: '($3 == 0) {print}' /etc/passwd This should print only one line, for the user root. If any account other than root has a UID of 0, this is a finding.
212	V-38501	medium	The system must disable accounts after excessive login failures within a 15-minute interval.	Locking out user accounts after a number of incorrect attempts within a specific period of time prevents direct password guessing attacks.	None	SV-50302r4_rule	F-43448r6_fix	Utilizing "pam_faillock.so", the "fail_interval" directive configures the system to lock out accounts after a number of incorrect logon attempts. Modify the content of both "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" as follows: Add the following line immediately before the "pam_unix.so" statement in the "AUTH" section: auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately after the "pam_unix.so" statement in the "AUTH" section: auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately before the "pam_unix.so" statement in the "ACCOUNT" section: account required pam_faillock.so Note that any updates made to "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" may be overwritten by the "authconfig" program. The "authconfig" program should not be used.	C-46058r2_chk	To ensure the failed password attempt policy is configured correctly, run the following command: $ grep pam_faillock /etc/pam.d/system-auth /etc/pam.d/password-auth For each file, the output should show "fail_interval=<interval-in-seconds>" where "interval-in-seconds" is 900 (15 minutes) or greater. If the "fail_interval" parameter is not set, the default setting of 900 seconds is acceptable. If that is not the case, this is a finding.
213	V-38502	medium	The /etc/shadow file must be owned by root.	The "/etc/shadow" file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.	None	SV-50303r1_rule	F-43449r1_fix	To properly set the owner of "/etc/shadow", run the command: # chown root /etc/shadow	C-46059r1_chk	To check the ownership of "/etc/shadow", run the command: $ ls -l /etc/shadow If properly configured, the output should indicate the following owner: "root" If it does not, this is a finding.
214	V-38503	medium	The /etc/shadow file must be group-owned by root.	The "/etc/shadow" file stores password hashes. Protection of this file is critical for system security.	None	SV-50304r1_rule	F-43450r1_fix	To properly set the group owner of "/etc/shadow", run the command: # chgrp root /etc/shadow	C-46060r1_chk	To check the group ownership of "/etc/shadow", run the command: $ ls -l /etc/shadow If properly configured, the output should indicate the following group-owner. "root" If it does not, this is a finding.
215	V-38621	medium	The system clock must be synchronized to an authoritative DoD time source.	Synchronizing with an NTP server makes it possible to collate system logs from multiple sources or correlate computer events with real time events. Using a trusted NTP server provided by your organization is recommended.	None	SV-50422r1_rule	F-43570r1_fix	To specify a remote NTP server for time synchronization, edit the file "/etc/ntp.conf". Add or correct the following lines, substituting the IP or hostname of a remote NTP server for ntpserver. server [ntpserver] This instructs the NTP software to contact that remote server to obtain time data.	C-46180r1_chk	A remote NTP server should be configured for time synchronization. To verify one is configured, open the following file. /etc/ntp.conf In the file, there should be a section similar to the following: # --- OUR TIMESERVERS ----- server [ntpserver] If this is not the case, this is a finding.
216	V-38620	medium	The system clock must be synchronized continuously, or at least daily.	Enabling the "ntpd" service ensures that the "ntpd" service will be running and that the system will synchronize its time to any servers specified. This is important whether the system is configured to be a client (and synchronize only its own clock) or it is also acting as an NTP server to other systems. Synchronizing time is essential for authentication services such as Kerberos, but it is also important for maintaining accurate logs and auditing possible security breaches.	None	SV-50421r1_rule	F-43568r1_fix	The "ntpd" service can be enabled with the following command: # chkconfig ntpd on # service ntpd start	C-46178r1_chk	Run the following command to determine the current status of the "ntpd" service: # service ntpd status If the service is enabled, it should return the following: ntpd is running... If the service is not running, this is a finding.
217	V-38623	medium	All rsyslog-generated log files must have mode 0600 or less permissive.	Log files can contain valuable information regarding system configuration. If the system log files are not protected, unauthorized users could change the logged data, eliminating their forensic value.	None	SV-50424r2_rule	F-43571r1_fix	The file permissions for all log files written by rsyslog should be set to 600, or more restrictive. These log files are determined by the second part of each Rule line in "/etc/rsyslog.conf" and typically all appear in "/var/log". For each log file [LOGFILE] referenced in "/etc/rsyslog.conf", run the following command to inspect the file's permissions: $ ls -l [LOGFILE] If the permissions are not 600 or more restrictive, run the following command to correct this: # chmod 0600 [LOGFILE]	C-46181r2_chk	The file permissions for all log files written by rsyslog should be set to 600, or more restrictive. These log files are determined by the second part of each Rule line in "/etc/rsyslog.conf" and typically all appear in "/var/log". For each log file [LOGFILE] referenced in "/etc/rsyslog.conf", run the following command to inspect the file's permissions: $ ls -l [LOGFILE] The permissions should be 600, or more restrictive. Some log files referenced in /etc/rsyslog.conf may be created by other programs and may require exclusion from consideration. If the permissions are not correct, this is a finding.
218	V-38587	high	The telnet-server package must not be installed.	Removing the "telnet-server" package decreases the risk of the unencrypted telnet service's accidental (or intentional) activation. Mitigation: If the telnet-server package is configured to only allow encrypted sessions, such as with Kerberos or the use of encrypted network tunnels, the risk of exposing sensitive information is mitigated.	None	SV-50388r1_rule	F-43535r1_fix	The "telnet-server" package can be uninstalled with the following command: # yum erase telnet-server	C-46144r1_chk	Run the following command to determine if the "telnet-server" package is installed: # rpm -q telnet-server If the package is installed, this is a finding.
219	V-38625	medium	If the system is using LDAP for authentication or account information, the system must use a TLS connection using FIPS 140-2 approved cryptographic algorithms.	The ssl directive specifies whether to use ssl or not. If not specified it will default to "no". It should be set to "start_tls" rather than doing LDAP over SSL.	None	SV-50426r1_rule	F-43574r1_fix	Configure LDAP to enforce TLS use. First, edit the file "/etc/pam_ldap.conf", and add or correct the following lines: ssl start_tls Then review the LDAP server and ensure TLS has been configured.	C-46184r1_chk	If the system does not use LDAP for authentication or account information, this is not applicable. To ensure LDAP is configured to use TLS for all transactions, run the following command: $ grep start_tls /etc/pam_ldap.conf If no lines are returned, this is a finding.
220	V-38624	low	System logs must be rotated daily.	Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.	None	SV-50425r1_rule	F-43573r1_fix	The "logrotate" service should be installed or reinstalled if it is not installed and operating properly, by running the following command: # yum reinstall logrotate	C-46183r1_chk	Run the following commands to determine the current status of the "logrotate" service: # grep logrotate /var/log/cron* If the logrotate service is not run on a daily basis by cron, this is a finding.
221	V-38627	low	The openldap-servers package must not be installed unless required.	Unnecessary packages should not be installed to decrease the attack surface of the system.	None	SV-50428r1_rule	F-43577r1_fix	The "openldap-servers" package should be removed if not in use. Is this machine the OpenLDAP server? If not, remove the package. # yum erase openldap-servers The openldap-servers RPM is not installed by default on RHEL6 machines. It is needed only by the OpenLDAP server, not by the clients which use LDAP for authentication. If the system is not intended for use as an LDAP Server it should be removed.	C-46187r1_chk	To verify the "openldap-servers" package is not installed, run the following command: $ rpm -q openldap-servers The output should show the following. package openldap-servers is not installed If it does not, this is a finding.
222	V-38626	medium	The LDAP client must use a TLS connection using trust certificates signed by the site CA.	The tls_cacertdir or tls_cacertfile directives are required when tls_checkpeer is configured (which is the default for openldap versions 2.1 and up). These directives define the path to the trust certificates signed by the site CA.	None	SV-50427r1_rule	F-43575r1_fix	Ensure a copy of the site's CA certificate has been placed in the file "/etc/pki/tls/CA/cacert.pem". Configure LDAP to enforce TLS use and to trust certificates signed by the site's CA. First, edit the file "/etc/pam_ldap.conf", and add or correct either of the following lines: tls_cacertdir /etc/pki/tls/CA or tls_cacertfile /etc/pki/tls/CA/cacert.pem Then review the LDAP server and ensure TLS has been configured.	C-46185r1_chk	If the system does not use LDAP for authentication or account information, this is not applicable. To ensure TLS is configured with trust certificates, run the following command: # grep cert /etc/pam_ldap.conf If there is no output, or the lines are commented out, this is a finding.
223	V-38629	medium	The graphical desktop environment must set the idle timeout to no more than 15 minutes.	Setting the idle delay controls when the screensaver will start, and can be combined with screen locking to prevent access from passersby.	None	SV-50430r3_rule	F-43578r1_fix	Run the following command to set the idle time-out value for inactivity in the GNOME desktop to 15 minutes: # gconftool-2 \ --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type int \ --set /apps/gnome-screensaver/idle_delay 15	C-46188r3_chk	If the GConf2 package is not installed, this is not applicable. To check the current idle time-out value, run the following command: $ gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/idle_delay If properly configured, the output should be "15". If it is not, this is a finding.
224	V-38628	medium	The operating system must produce audit records containing sufficient information to establish the identity of any user/subject associated with the event.	Ensuring the "auditd" service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.	None	SV-50429r2_rule	F-43576r2_fix	The "auditd" service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The "auditd" service can be enabled with the following commands: # chkconfig auditd on # service auditd start	C-46186r1_chk	Run the following command to determine the current status of the "auditd" service: # service auditd status If the service is enabled, it should return the following: auditd is running... If the service is not running, this is a finding.
225	V-38588	medium	The system must not permit interactive boot.	Using interactive boot, the console user could disable auditing, firewalls, or other services, weakening system security.	None	SV-50389r1_rule	F-43536r1_fix	To disable the ability for users to perform interactive startups, edit the file "/etc/sysconfig/init". Add or correct the line: PROMPT=no The "PROMPT" option allows the console user to perform an interactive system startup, in which it is possible to select the set of services which are started on boot.	C-46146r1_chk	To check whether interactive boot is disabled, run the following command: $ grep PROMPT /etc/sysconfig/init If interactive boot is disabled, the output will show: PROMPT=no If it does not, this is a finding.
226	V-38589	high	The telnet daemon must not be running.	The telnet protocol uses unencrypted network communication, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network. The telnet protocol is also subject to man-in-the-middle attacks. Mitigation: If an enabled telnet daemon is configured to only allow encrypted sessions, such as with Kerberos or the use of encrypted network tunnels, the risk of exposing sensitive information is mitigated.	None	SV-50390r2_rule	F-43537r1_fix	The "telnet" service can be disabled with the following command: # chkconfig telnet off	C-46147r3_chk	To check that the "telnet" service is disabled in system boot configuration, run the following command: # chkconfig "telnet" --list Output should indicate the "telnet" service has either not been installed, or has been disabled, as shown in the example below: # chkconfig "telnet" --list telnet off OR error reading information on service telnet: No such file or directory If the service is running, this is a finding.
227	V-38584	low	The xinetd service must be uninstalled if no network services utilizing it are enabled.	Removing the "xinetd" package decreases the risk of the xinetd service's accidental (or intentional) activation.	None	SV-50385r1_rule	F-43532r1_fix	The "xinetd" package can be uninstalled with the following command: # yum erase xinetd	C-46142r1_chk	If network services are using the xinetd service, this is not applicable. Run the following command to determine if the "xinetd" package is installed: # rpm -q xinetd If the package is installed, this is a finding.
228	V-38694	low	The operating system must manage information system identifiers for users and devices by disabling the user identifier after an organization defined time period of inactivity.	Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.	None	SV-50495r1_rule	F-43643r2_fix	To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following lines in "/etc/default/useradd", substituting "[NUM_DAYS]" appropriately: INACTIVE=[NUM_DAYS] A value of 35 is recommended. If a password is currently on the verge of expiration, then 35 days remain until the account is automatically disabled. However, if the password will not expire for another 60 days, then 95 days could elapse until the account would be automatically disabled. See the "useradd" man page for more information. Determining the inactivity timeout must be done with careful consideration of the length of a "normal" period of inactivity for users in the particular environment. Setting the timeout too low incurs support costs and also has the potential to impact availability of the system to legitimate users.	C-46256r1_chk	To verify the "INACTIVE" setting, run the following command: grep "INACTIVE" /etc/default/useradd The output should indicate the "INACTIVE" configuration option is set to an appropriate integer as shown in the example below: # grep "INACTIVE" /etc/default/useradd INACTIVE=35 If it does not, this is a finding.
229	V-38700	medium	The operating system must provide a near real-time alert when any of the organization defined list of compromise or potential compromise indicators occurs.	By default, AIDE does not install itself for periodic execution. Periodically running AIDE may reveal unexpected changes in installed files.	None	SV-50501r2_rule	F-43649r1_fix	AIDE should be executed on a periodic basis to check for changes. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab: 05 4 * * * root /usr/sbin/aide --check AIDE can be executed periodically through other means; this is merely one example.	C-46262r2_chk	To determine that periodic AIDE execution has been scheduled, run the following command: # grep aide /etc/crontab /etc/cron.*/* If there is no output, this is a finding.
230	V-38695	medium	A file integrity tool must be used at least weekly to check for unauthorized file changes, particularly the addition of unauthorized system libraries or binaries, or for unauthorized modification to authorized system libraries or binaries.	By default, AIDE does not install itself for periodic execution. Periodically running AIDE may reveal unexpected changes in installed files.	None	SV-50496r2_rule	F-43644r1_fix	AIDE should be executed on a periodic basis to check for changes. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab: 05 4 * * * root /usr/sbin/aide --check AIDE can be executed periodically through other means; this is merely one example.	C-46257r2_chk	To determine that periodic AIDE execution has been scheduled, run the following command: # grep aide /etc/crontab /etc/cron.*/* If there is no output or if aide is not run at least weekly, this is a finding.
231	V-38701	high	The TFTP daemon must operate in secure mode which provides access only to a single directory on the host file system.	Using the "-s" option causes the TFTP service to only serve files from the given directory. Serving files from an intentionally specified directory reduces the risk of sharing files which should remain private.	None	SV-50502r1_rule	F-43650r1_fix	If running the "tftp" service is necessary, it should be configured to change its root directory at startup. To do so, ensure "/etc/xinetd.d/tftp" includes "-s" as a command line argument, as shown in the following example (which is also the default): server_args = -s /var/lib/tftpboot	C-46263r1_chk	Verify "tftp" is configured by with the "-s" option by running the following command: grep "server_args" /etc/xinetd.d/tftp The output should indicate the "server_args" variable is configured with the "-s" flag, matching the example below: # grep "server_args" /etc/xinetd.d/tftp server_args = -s /var/lib/tftpboot If it does not, this is a finding.
232	V-38483	medium	The system package management tool must cryptographically verify the authenticity of system software packages during installation.	Ensuring the validity of packages' cryptographic signatures prior to installation ensures the provenance of the software and protects against malicious tampering.	None	SV-50283r1_rule	F-43429r1_fix	The "gpgcheck" option should be used to ensure checking of an RPM package's signature always occurs prior to its installation. To configure yum to check package signatures before installing them, ensure the following line appears in "/etc/yum.conf" in the "[main]" section: gpgcheck=1	C-46039r1_chk	To determine whether "yum" is configured to use "gpgcheck", inspect "/etc/yum.conf" and ensure the following appears in the "[main]" section: gpgcheck=1 A value of "1" indicates that "gpgcheck" is enabled. Absence of a "gpgcheck" line or a setting of "0" indicates that it is disabled. If GPG checking is not enabled, this is a finding. If the "yum" system package management tool is not used to update the system, verify with the SA that installed packages are cryptographically signed.
233	V-38545	low	The audit system must be configured to audit all discretionary access control permission modifications using chown.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50346r3_rule	F-43493r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S chown -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S chown -F auid=0 -k perm_mod	C-46103r2_chk	To determine if the system is configured to audit calls to the "chown" system call, run the following command: $ sudo grep -w "chown" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
234	V-38539	medium	The system must be configured to use TCP syncookies when experiencing a TCP SYN flood.	A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.	None	SV-50340r2_rule	F-43487r1_fix	To set the runtime status of the "net.ipv4.tcp_syncookies" kernel parameter, run the following command: # sysctl -w net.ipv4.tcp_syncookies=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.tcp_syncookies = 1	C-46097r2_chk	The status of the "net.ipv4.tcp_syncookies" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.tcp_syncookies The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.tcp_syncookies /etc/sysctl.conf If the correct value is not returned, this is a finding.
235	V-38538	low	The operating system must automatically audit account termination.	In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.	None	SV-50339r1_rule	F-43486r1_fix	Add the following to "/etc/audit/audit.rules", in order to capture events that modify account changes: # audit_account_changes -w /etc/group -p wa -k audit_account_changes -w /etc/passwd -p wa -k audit_account_changes -w /etc/gshadow -p wa -k audit_account_changes -w /etc/shadow -p wa -k audit_account_changes -w /etc/security/opasswd -p wa -k audit_account_changes	C-46096r1_chk	To determine if the system is configured to audit account changes, run the following command: auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow|/etc/security/opasswd)' If the system is configured to watch for account changes, lines should be returned for each file specified (and with "perm=wa" for each). If the system is not configured to audit account changes, this is a finding.
236	V-38697	low	The sticky bit must be set on all public directories.	Failing to set the sticky bit on public directories allows unauthorized users to delete files in the directory structure. The only authorized public directories are those temporary directories supplied with the system, or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system, and by users for temporary file storage - such as /tmp - and for directories requiring global read/write access.	None	SV-50498r2_rule	F-43646r1_fix	When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky bit, any user with write access to a directory may remove any file in the directory. Setting the sticky bit prevents users from removing each other's files. In cases where there is no reason for a directory to be world-writable, a better solution is to remove that permission rather than to set the sticky bit. However, if a directory is used by a particular application, consult that application's documentation instead of blindly changing modes. To set the sticky bit on a world-writable directory [DIR], run the following command: # chmod +t [DIR]	C-46259r4_chk	To find world-writable directories that lack the sticky bit, run the following command for each local partition [PART]: # find [PART] -xdev -type d -perm -002 \! -perm -1000 If any world-writable directories are missing the sticky bit, this is a finding.
237	V-38531	low	The operating system must automatically audit account creation.	In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.	None	SV-50332r1_rule	F-43480r1_fix	Add the following to "/etc/audit/audit.rules", in order to capture events that modify account changes: # audit_account_changes -w /etc/group -p wa -k audit_account_changes -w /etc/passwd -p wa -k audit_account_changes -w /etc/gshadow -p wa -k audit_account_changes -w /etc/shadow -p wa -k audit_account_changes -w /etc/security/opasswd -p wa -k audit_account_changes	C-46090r1_chk	To determine if the system is configured to audit account changes, run the following command: auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow|/etc/security/opasswd)' If the system is configured to watch for account changes, lines should be returned for each file specified (and with "perm=wa" for each). If the system is not configured to audit account changes, this is a finding.
238	V-38513	medium	The systems local IPv4 firewall must implement a deny-all, allow-by-exception policy for inbound packets.	In "iptables" the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to "DROP" implements proper design for a firewall, i.e., any packets which are not explicitly permitted should not be accepted.	None	SV-50314r1_rule	F-43460r1_fix	To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in "/etc/sysconfig/iptables": :INPUT DROP [0:0]	C-46070r1_chk	Inspect the file "/etc/sysconfig/iptables" to determine the default policy for the INPUT chain. It should be set to DROP. # grep ":INPUT" /etc/sysconfig/iptables If the default policy for the INPUT chain is not set to DROP, this is a finding.
239	V-38533	low	The system must ignore ICMPv4 redirect messages by default.	This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.	None	SV-50334r3_rule	F-43481r1_fix	To set the runtime status of the "net.ipv4.conf.default.accept_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.accept_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.default.accept_redirects = 0	C-46091r2_chk	The status of the "net.ipv4.conf.default.accept_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.accept_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.default.accept_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
240	V-38532	medium	The system must not accept ICMPv4 secure redirect packets by default.	Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.	None	SV-50333r2_rule	F-43479r1_fix	To set the runtime status of the "net.ipv4.conf.default.secure_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.secure_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.default.secure_redirects = 0	C-46089r2_chk	The status of the "net.ipv4.conf.default.secure_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.secure_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.default.secure_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.
241	V-38535	low	The system must not respond to ICMPv4 sent to a broadcast address.	Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.	None	SV-50336r2_rule	F-43483r1_fix	To set the runtime status of the "net.ipv4.icmp_echo_ignore_broadcasts" kernel parameter, run the following command: # sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.icmp_echo_ignore_broadcasts = 1	C-46093r2_chk	The status of the "net.ipv4.icmp_echo_ignore_broadcasts" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.icmp_echo_ignore_broadcasts The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.icmp_echo_ignore_broadcasts /etc/sysctl.conf If the correct value is not returned, this is a finding.
242	V-38534	low	The operating system must automatically audit account modification.	In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.	None	SV-50335r1_rule	F-43482r1_fix	Add the following to "/etc/audit/audit.rules", in order to capture events that modify account changes: # audit_account_changes -w /etc/group -p wa -k audit_account_changes -w /etc/passwd -p wa -k audit_account_changes -w /etc/gshadow -p wa -k audit_account_changes -w /etc/shadow -p wa -k audit_account_changes -w /etc/security/opasswd -p wa -k audit_account_changes	C-46092r1_chk	To determine if the system is configured to audit account changes, run the following command: auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow|/etc/security/opasswd)' If the system is configured to watch for account changes, lines should be returned for each file specified (and with "perm=wa" for each). If the system is not configured to audit account changes, this is a finding.
243	V-38655	low	The noexec option must be added to removable media partitions.	Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.	None	SV-50456r1_rule	F-43605r1_fix	The "noexec" mount option prevents the direct execution of binaries on the mounted filesystem. Users should not be allowed to execute binaries that exist on partitions mounted from removable media (such as a USB key). The "noexec" option prevents code from being executed directly from the media itself, and may therefore provide a line of defense against certain types of worms or malicious code. Add the "noexec" option to the fourth column of "/etc/fstab" for the line which controls mounting of any removable media partitions.	C-46216r1_chk	To verify that binaries cannot be directly executed from removable media, run the following command: # grep noexec /etc/fstab The output should show "noexec" in use. If it does not, this is a finding.
244	V-38512	medium	The operating system must prevent public IPv4 access into an organizations internal networks, except as appropriately mediated by managed interfaces employing boundary protection devices.	The "iptables" service provides the system's host-based firewalling capability for IPv4 and ICMP.	None	SV-50313r2_rule	F-43459r2_fix	The "iptables" service can be enabled with the following commands: # chkconfig iptables on # service iptables start	C-46069r2_chk	If the system is a cross-domain system, this is not applicable. Run the following command to determine the current status of the "iptables" service: # service iptables status If the service is not running, it should return the following: iptables: Firewall is not running. If the service is not running, this is a finding.
245	V-38438	low	Auditing must be enabled at boot by setting a kernel parameter.	Each process on the system carries an "auditable" flag which indicates whether its activities can be audited. Although "auditd" takes care of enabling this for all processes which launch after it does, adding the kernel argument ensures it is set for every process during boot.	None	SV-50238r2_rule	F-43382r2_fix	To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument "audit=1" to the kernel line in "/etc/grub.conf", in the manner below: kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1 UEFI systems may prepend "/boot" to the "/vmlinuz-version" argument.	C-45992r2_chk	Inspect the kernel boot arguments (which follow the word "kernel") in "/etc/grub.conf". If they include "audit=1", then auditing is enabled at boot time. If auditing is not enabled at boot time, this is a finding.
246	V-38439	medium	The system must provide automated support for account management functions.	A comprehensive account management process that includes automation helps to ensure the accounts designated as requiring attention are consistently and promptly addressed. Enterprise environments make user account management challenging and complex. A user management process requiring administrators to manually address account management functions adds risk of potential oversight.	None	SV-50239r1_rule	F-43384r1_fix	Implement an automated system for managing user accounts that minimizes the risk of errors, either intentional or deliberate. If possible, this system should integrate with an existing enterprise user management system, such as, one based Active Directory or Kerberos.	C-45994r1_chk	Interview the SA to determine if there is an automated system for managing user accounts, preferably integrated with an existing enterprise user management system. If there is not, this is a finding.
247	V-38692	low	Accounts must be locked upon 35 days of inactivity.	Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.	None	SV-50493r1_rule	F-43641r2_fix	To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following lines in "/etc/default/useradd", substituting "[NUM_DAYS]" appropriately: INACTIVE=[NUM_DAYS] A value of 35 is recommended. If a password is currently on the verge of expiration, then 35 days remain until the account is automatically disabled. However, if the password will not expire for another 60 days, then 95 days could elapse until the account would be automatically disabled. See the "useradd" man page for more information. Determining the inactivity timeout must be done with careful consideration of the length of a "normal" period of inactivity for users in the particular environment. Setting the timeout too low incurs support costs and also has the potential to impact availability of the system to legitimate users.	C-46254r2_chk	To verify the "INACTIVE" setting, run the following command: grep "INACTIVE" /etc/default/useradd The output should indicate the "INACTIVE" configuration option is set to an appropriate integer as shown in the example below: # grep "INACTIVE" /etc/default/useradd INACTIVE=35 If it does not, this is a finding.
248	V-38638	medium	The graphical desktop environment must have automatic lock enabled.	Enabling the activation of the screen lock after an idle period ensures password entry will be required in order to access the system, preventing access by passersby.	None	SV-50439r3_rule	F-43587r1_fix	Run the following command to activate locking of the screensaver in the GNOME desktop when it is activated: # gconftool-2 --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type bool \ --set /apps/gnome-screensaver/lock_enabled true	C-46198r3_chk	If the GConf2 package is not installed, this is not applicable. To check the status of the idle screen lock activation, run the following command: $ gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/lock_enabled If properly configured, the output should be "true". If it is not, this is a finding.
249	V-38639	low	The system must display a publicly-viewable pattern during a graphical desktop environment session lock.	Setting the screensaver mode to blank-only conceals the contents of the display from passersby.	None	SV-50440r3_rule	F-43588r2_fix	Run the following command to set the screensaver mode in the GNOME desktop to a blank screen: # gconftool-2 \ --direct \ --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \ --type string \ --set /apps/gnome-screensaver/mode blank-only	C-46199r4_chk	If the GConf2 package is not installed, this is not applicable. To ensure the screensaver is configured to be blank, run the following command: $ gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/mode If properly configured, the output should be "blank-only". If it is not, this is a finding.
250	V-38636	medium	The system must retain enough rotated audit logs to cover the required log retention period.	The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.	None	SV-50437r1_rule	F-43585r1_fix	Determine how many log files "auditd" should retain when it rotates logs. Edit the file "/etc/audit/auditd.conf". Add or modify the following line, substituting [NUMLOGS] with the correct value: num_logs = [NUMLOGS] Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.	C-46195r1_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine how many logs the system is configured to retain after rotation: "# grep num_logs /etc/audit/auditd.conf" num_logs = 5 If the overall system log file(s) retention hasn't been properly set up, this is a finding.
251	V-38637	medium	The system package management tool must verify contents of all files associated with the audit package.	The hash on important files like audit system executables should match the information given by the RPM database. Audit executables with erroneous hashes could be a sign of nefarious activity on the system.	None	SV-50438r2_rule	F-43586r1_fix	The RPM package management system can check the hashes of audit system package files. Run the following command to list which audit files on the system have hashes that differ from what is expected by the RPM database: # rpm -V audit | grep '^..5' A "c" in the second column indicates that a file is a configuration file, which may appropriately be expected to change. If the file that has changed was not expected to then refresh from distribution media or online repositories. rpm -Uvh [affected_package] OR yum reinstall [affected_package]	C-46196r3_chk	The following command will list which audit files on the system have file hashes different from what is expected by the RPM database. # rpm -V audit | awk '$1 ~ /..5/ && $2 != "c"' If there is output, this is a finding.
252	V-38634	medium	The system must rotate audit log files that reach the maximum file size.	Automatically rotating logs (by setting this to "rotate") minimizes the chances of the system unexpectedly running out of disk space by being overwhelmed with log data. However, for systems that must never discard log data, or which use external processes to transfer it and reclaim space, "keep_logs" can be employed.	None	SV-50435r2_rule	F-43583r1_fix	The default action to take when the logs reach their maximum size is to rotate the log files, discarding the oldest one. To configure the action taken by "auditd", add or correct the line in "/etc/audit/auditd.conf": max_log_file_action = [ACTION] Possible values for [ACTION] are described in the "auditd.conf" man page. These include: "ignore" "syslog" "suspend" "rotate" "keep_logs" Set the "[ACTION]" to "rotate" to ensure log rotation occurs. This is the default. The setting is case-insensitive.	C-46193r3_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine if the system is configured to rotate logs when they reach their maximum size: # grep max_log_file_action /etc/audit/auditd.conf max_log_file_action = rotate If the "keep_logs" option is configured for the "max_log_file_action" line in "/etc/audit/auditd.conf" and an alternate process is in place to ensure audit data does not overwhelm local audit storage, this is not a finding. If the system has not been properly set up to rotate audit logs, this is a finding.
253	V-38635	low	The audit system must be configured to audit all attempts to alter system time through adjtimex.	Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.	None	SV-50436r3_rule	F-43584r2_fix	On a 32-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules On a 64-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b64 -S adjtimex -k audit_time_rules The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules	C-46194r2_chk	To determine if the system is configured to audit calls to the "adjtimex" system call, run the following command: $ sudo grep -w "adjtimex" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If the system is not configured to audit time changes, this is a finding.
254	V-38696	medium	The operating system must employ automated mechanisms, per organization defined frequency, to detect the addition of unauthorized components/devices into the operating system.	By default, AIDE does not install itself for periodic execution. Periodically running AIDE may reveal unexpected changes in installed files.	None	SV-50497r2_rule	F-43645r1_fix	AIDE should be executed on a periodic basis to check for changes. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab: 05 4 * * * root /usr/sbin/aide --check AIDE can be executed periodically through other means; this is merely one example.	C-46258r2_chk	To determine that periodic AIDE execution has been scheduled, run the following command: # grep aide /etc/crontab /etc/cron.*/* If there is no output, this is a finding.
255	V-38633	medium	The system must set a maximum audit log file size.	The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.	None	SV-50434r1_rule	F-43582r1_fix	Determine the amount of audit data (in megabytes) which should be retained in each log file. Edit the file "/etc/audit/auditd.conf". Add or modify the following line, substituting the correct value for [STOREMB]: max_log_file = [STOREMB] Set the value to "6" (MB) or higher for general-purpose systems. Larger values, of course, support retention of even more audit data.	C-46192r1_chk	Inspect "/etc/audit/auditd.conf" and locate the following line to determine how much data the system will retain in each audit log file: "# grep max_log_file /etc/audit/auditd.conf" max_log_file = 6 If the system audit data threshold hasn't been properly set up, this is a finding.
256	V-38586	medium	The system must require authentication upon booting into single-user and maintenance modes.	This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.	None	SV-50387r1_rule	F-43534r1_fix	Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup. By default, no authentication is performed if single-user mode is selected. To require entry of the root password even if the system is started in single-user mode, add or correct the following line in the file "/etc/sysconfig/init": SINGLE=/sbin/sulogin	C-46145r1_chk	To check if authentication is required for single-user mode, run the following command: $ grep SINGLE /etc/sysconfig/init The output should be the following: SINGLE=/sbin/sulogin If the output is different, this is a finding.
257	V-38631	medium	The operating system must employ automated mechanisms to facilitate the monitoring and control of remote access methods.	Ensuring the "auditd" service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.	None	SV-50432r2_rule	F-43580r2_fix	The "auditd" service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The "auditd" service can be enabled with the following commands: # chkconfig auditd on # service auditd start	C-46190r1_chk	Run the following command to determine the current status of the "auditd" service: # service auditd status If the service is enabled, it should return the following: auditd is running... If the service is not running, this is a finding.
258	V-38614	high	The SSH daemon must not allow authentication using an empty password.	Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.	None	SV-50415r1_rule	F-43562r1_fix	To explicitly disallow remote login from accounts with empty passwords, add or correct the following line in "/etc/ssh/sshd_config": PermitEmptyPasswords no Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.	C-46172r1_chk	To determine how the SSH daemon's "PermitEmptyPasswords" option is set, run the following command: # grep -i PermitEmptyPasswords /etc/ssh/sshd_config If no line, a commented line, or a line indicating the value "no" is returned, then the required value is set. If the required value is not set, this is a finding.
259	V-38615	medium	The SSH daemon must be configured with the Department of Defense (DoD) login banner.	The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.	None	SV-50416r1_rule	F-43563r1_fix	To enable the warning banner and ensure it is consistent across the system, add or correct the following line in "/etc/ssh/sshd_config": Banner /etc/issue Another section contains information on how to create an appropriate system-wide warning banner.	C-46173r1_chk	To determine how the SSH daemon's "Banner" option is set, run the following command: # grep -i Banner /etc/ssh/sshd_config If a line indicating /etc/issue is returned, then the required value is set. If the required value is not set, this is a finding.
260	V-38622	medium	Mail relaying must be restricted.	This ensures "postfix" accepts mail messages (such as cron job reports) from the local system only, and not from the network, which protects it from network attack.	None	SV-50423r2_rule	F-43572r1_fix	Edit the file "/etc/postfix/main.cf" to ensure that only the following "inet_interfaces" line appears: inet_interfaces = localhost	C-46182r2_chk	If the system is an authorized mail relay host, this is not applicable. Run the following command to ensure postfix accepts mail messages from only the local system: $ grep inet_interfaces /etc/postfix/main.cf If properly configured, the output should show only "localhost". If it does not, this is a finding.
261	V-38616	low	The SSH daemon must not permit user environment settings.	SSH environment options potentially allow users to bypass access restriction in some configurations.	None	SV-50417r1_rule	F-43565r1_fix	To ensure users are not able to present environment options to the SSH daemon, add or correct the following line in "/etc/ssh/sshd_config": PermitUserEnvironment no	C-46175r1_chk	To ensure users are not able to present environment daemons, run the following command: # grep PermitUserEnvironment /etc/ssh/sshd_config If properly configured, output should be: PermitUserEnvironment no If it is not, this is a finding.
262	V-38563	low	The audit system must be configured to audit all discretionary access control permission modifications using removexattr.	The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.	None	SV-50364r3_rule	F-43511r2_fix	At a minimum, the audit system should collect file permission changes for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b32 -S removexattr -F auid=0 -k perm_mod If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 \ -k perm_mod -a always,exit -F arch=b64 -S removexattr -F auid=0 -k perm_mod	C-46121r2_chk	To determine if the system is configured to audit calls to the "removexattr" system call, run the following command: $ sudo grep -w "removexattr" /etc/audit/audit.rules If the system is configured to audit this activity, it will return several lines. If no line is returned, this is a finding.
263	V-38617	medium	The SSH daemon must be configured to use only FIPS 140-2 approved ciphers.	Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.	None	SV-50418r1_rule	F-43566r1_fix	Limit the ciphers to those algorithms which are FIPS-approved. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode. The following line in "/etc/ssh/sshd_config" demonstrates use of FIPS-approved ciphers: Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc The man page "sshd_config(5)" contains a list of supported ciphers.	C-46176r1_chk	Only FIPS-approved ciphers should be used. To verify that only FIPS-approved ciphers are in use, run the following command: # grep Ciphers /etc/ssh/sshd_config The output should contain only those ciphers which are FIPS-approved, namely, the AES and 3DES ciphers. If that is not the case, this is a finding.
264	V-38610	low	The SSH daemon must set a timeout count on idle sessions.	This ensures a user login will be terminated as soon as the "ClientAliveCountMax" is reached.	None	SV-50411r1_rule	F-43558r1_fix	To ensure the SSH idle timeout occurs precisely when the "ClientAliveCountMax" is set, edit "/etc/ssh/sshd_config" as follows: ClientAliveCountMax 0	C-46168r1_chk	To ensure the SSH idle timeout will occur when the "ClientAliveCountMax" is set, run the following command: # grep ClientAliveCountMax /etc/ssh/sshd_config If properly configured, output should be: ClientAliveCountMax 0 If it is not, this is a finding.
265	V-38611	medium	The SSH daemon must ignore .rhosts files.	SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.	None	SV-50412r1_rule	F-43559r1_fix	SSH can emulate the behavior of the obsolete rsh command in allowing users to enable insecure access to their accounts via ".rhosts" files. To ensure this behavior is disabled, add or correct the following line in "/etc/ssh/sshd_config": IgnoreRhosts yes	C-46169r1_chk	To determine how the SSH daemon's "IgnoreRhosts" option is set, run the following command: # grep -i IgnoreRhosts /etc/ssh/sshd_config If no line, a commented line, or a line indicating the value "yes" is returned, then the required value is set. If the required value is not set, this is a finding.