Oracle Linux 5 Security Technical Implementation Guide

V1R13 2018-10-03       U_Oracle_Linux_5_STIG_V1R13_Manual-xccdf.xml
V1R12 2018-03-01       U_Oracle_Linux_5_STIG_V1R12_Manual-xccdf.xml
The Oracle Linux 5 Security Technical Implementation Guide (STIG) is published as a tool to improve the security of Department of Defense (DoD) information systems. Comments or proposed revisions to this document should be sent via e-mail to the following address: [email protected]
Comparison
All 571
No Change 570
Updated 0
Added 1
Removed 0
V-756 No Change
Findings ID: GEN000020 Rule ID: SV-63087r2_rule Severity: medium CCI: CCI-000213

Discussion

If the system does not require valid root authentication before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system.System Administrator

Checks

Check if the system requires a password for entering single-user mode.
# grep ':S:' /etc/inittab
If /sbin/sulogin is not listed, this is a finding.

Fix

Edit /etc/inittab and set sulogin to run in single-user mode.
Example line in /etc/inittab:
~:S:wait:/sbin/sulogin

Note: The first field in the /etc/inittab line may be any sequence of 1-4 characters.
V-760 No Change
Findings ID: GEN000280 Rule ID: SV-63187r2_rule Severity: medium CCI: CCI-000770

Discussion

Shared accounts (accounts where two or more people log in with the same user identification) do not provide identification and authentication. There is no way to provide for non-repudiation or individual accountability.trueSystem AdministratorInformation Assurance Officer

Checks

Use the last command to check for multiple accesses to an account from different workstations/IP addresses.

# last -w

If users log directly on to accounts, rather than using the switch user (su) command from their own named account to access them, this is a finding (such as logging directly onto oracle).

Verify with the SA or the ISSO on documentation for users/administrators to log on to their own accounts first and then switch user (su) to the account to be shared has been maintained, including requirements and procedures. If no such documentation exists, this is a finding.

Fix

Use the switch user (su) command from a named account login to access shared accounts. Document requirements and procedures for users/administrators to log into their own accounts first and then switch user (su) to the account to be shared.
V-761 No Change
Findings ID: GEN000300 Rule ID: SV-63251r1_rule Severity: medium CCI: CCI-000764

Discussion

A unique user name is the first part of the identification and authentication process. If user names are not unique, there can be no accountability on the system for auditing purposes. Multiple accounts sharing the same name could result in the denial of service to one or both of the accounts or unauthorized access to files or privileges.System Administrator

Checks

Check the system for duplicate account names.

Example:
# pwck -r

If any duplicate account names are found, this is a finding.

Fix

Change user account names, or delete accounts, so each account has a unique name.
V-762 No Change
Findings ID: GEN000320 Rule ID: SV-63255r1_rule Severity: medium CCI: CCI-000764

Discussion

Accounts sharing a UID have full access to each others' files. This has the same effect as sharing a login. There is no way to assure identification, authentication, and accountability because the system sees them as the same user. If the duplicate UID is 0, this gives potential intruders another privileged account to attack.System Administrator

Checks

Perform the following to ensure there are no duplicate UIDs:

# cut -d: -f3 /etc/passwd | uniq -d

If any duplicate UIDs are found, this is a finding.

Fix

Edit user accounts to provide unique UIDs for each account.
V-763 No Change
Findings ID: GEN000400 Rule ID: SV-63333r1_rule Severity: medium CCI: CCI-000048

Discussion

Failure to display the logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.System Administrator

Checks

Access the system console and make a login attempt. Check for either of the following login banners based on the character limitations imposed by the system. An exact match is required. If one of these banners is not displayed, this is a finding.

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.

Fix

Edit /etc/issue and add one of the DoD login banners (based on the character limitations imposed by the system).

DoD Login Banners:

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.
V-765 No Change
Findings ID: GEN000440 Rule ID: SV-63363r1_rule Severity: medium CCI: CCI-000126

Discussion

Monitoring and recording successful and unsuccessful logins assists in tracking unauthorized access to the system. Without this logging, the ability to track unauthorized activity to specific user accounts may be diminished.System Administrator

Checks

Determine if all logon attempts are being logged.

Procedure:
Verify successful logins are being logged:
# last -R | more
If the command does not return successful logins, this is a finding.

Verify if unsuccessful logons are being logged:
# lastb -R | more
If the command does not return unsuccessful logins, this is a finding.

Fix

Make sure the collection files exist.
Procedure:
If there are no successful logins being returned from the "last" command, create /var/log/wtmp:
# touch /var/log/wtmp

If there are no unsuccessful logins being returned from the "lastb" command, create /var/log/btmp:
# touch /var/log/btmp
V-766 No Change
Findings ID: GEN000460 Rule ID: SV-63383r1_rule Severity: medium CCI: CCI-000044

Discussion

Disabling accounts after a limited number of unsuccessful login attempts improves protection against password guessing attacks.System Administrator

Checks

Check the pam_tally configuration.
# more /etc/pam.d/system-auth
Confirm the following line is configured, before any "auth sufficient" lines:
auth required pam_tally2.so deny=3
If no such line is found, this is a finding.

Fix

By default link /etc/pam.d/system-auth points to /etc/pam.d/system-auth-ac which is the file maintained by the authconfig utility. In order to add pam options other than those available via the utility create /etc/pam.d/system-auth-local with the options and including system-auth-ac. In order to set the account lockout to three failed attempts the content should be similar to:

auth required pam_access.so
auth required pam_tally2.so deny=3
auth include system-auth-ac
account required pam_tally2.so
account include system-auth-ac
password include system-auth-ac
session include system-auth-ac

Once system-auth-local is written reset the /etc/pam.d/system-auth to point to system-auth-local. This is necessary because authconfig writes directly to system-auth-ac so any changes made by hand will be lost if authconfig is run.
V-768 No Change
Findings ID: GEN000480 Rule ID: SV-63391r1_rule Severity: medium CCI: CCI-002238

Discussion

Enforcing a delay between successive failed login attempts increases protection against automated password guessing attacks.System Administrator

Checks

Check the value of the FAIL_DELAY variable and the ability to use it.

Procedure:
# grep FAIL_DELAY /etc/login.defs
If the value does not exist, or is less than 4, this is a finding.

Check for the use of pam_faildelay.
# grep pam_faildelay /etc/pam.d/system-auth*
If pam_faildelay.so module is not present, this is a finding.

If pam_faildelay is present only in /etc/pam.d/system-auth-ac:
ensure that /etc/pam.d/system-auth includes /etc/pam.d/system-auth-ac.
#grep system-auth-ac /etc/pam.d/system-auth

This should return:
auth include system-auth-ac
account include system-auth-ac
password include system-auth-ac
session include system-auth-ac

/etc/pam.d/system-auth-ac should only be included by /etc/pam.d/system-auth. All other pam files should include /etc/pam.d/system-auth.

If pam_faildelay is not defined in /etc/pam.d/system-auth either directly or through inclusion of system-auth-ac, this is a finding.

Fix

Add the pam_faildelay module and set the FAIL_DELAY variable.

Procedure:

Edit /etc/login.defs and set the value of the FAIL_DELAY variable to 4 or more.

The default link /etc/pam.d/system-auth points to /etc/pam.d/system-auth-ac which is the file maintained by the authconfig utility. In order to add pam options other than those available via the utility create or modify /etc/pam.d/system-auth-local with the options and including system-auth-ac. For example:

auth required pam_access.so
auth optional pam_faildelay.so delay=4000000
auth include system-auth-ac
account include system-auth-ac
password include system-auth-ac
session include system-auth-ac

Once system-auth-local is written ensure the /etc/pam.d/system-auth points to system-auth-local. This is necessary because authconfig writes directly to system-auth-ac so any manual changes made will be lost if authconfig is run.
V-769 No Change
Findings ID: GEN000520 Rule ID: SV-63649r1_rule Severity: medium CCI: CCI-000225

Discussion

If an application is providing a continuous display and is running with root privileges, unauthorized users could interrupt the process and gain root access to the system.System Administrator

Checks

If there is an application running on the system continuously in use (such as a network monitoring application), ask the SA what the name of the application is.
Verify documentation exists for the requirement and justification of the application. If no documentation exists, this is a finding.
Execute "ps -ef | more" to determine which user owns the process(es) associated with the application. If the owner is root, this is a finding.

Fix

Configure the system so the owner of a session requires a continuous screen display, such as a network management display, is not root. Ensure the display is also located in a secure, controlled access area. Document and justify this requirement and ensure the terminal and keyboard for the display (or workstation) are secure from all but authorized personnel by maintaining them in a secure area, in a locked cabinet where a swipe card, or other positive forms of identification, must be used to gain entry.
V-770 No Change
Findings ID: GEN000560 Rule ID: SV-63787r1_rule Severity: high CCI: CCI-000366

Discussion

If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. If the root user is configured without a password, the entire system may be compromised. For user accounts not using password authentication, the account must be configured with a password lock value instead of a blank or null value. System Administrator

Checks

Verify the system will not log in accounts with blank passwords.
# grep nullok /etc/pam.d/system-auth /etc/pam.d/system-auth-ac
If an entry for nullok is found, this is a finding on Linux.

Fix

Edit /etc/pam.d/system-auth and remove the "nullok" setting.
V-773 No Change
Findings ID: GEN000880 Rule ID: SV-64341r1_rule Severity: medium CCI: CCI-000366

Discussion

If an account has a UID of 0, it has root authority. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account.
System Administrator

Checks

Check the system for duplicate UID 0 assignments by listing all accounts assigned UID 0.

Procedure:
# awk -F: '($3 == 0) { print $1 }' /etc/passwd

If any accounts other than root are assigned UID 0, this is a finding.

Fix

Remove or change the UID of accounts other than root that have UID 0.
V-774 No Change
Findings ID: GEN000900 Rule ID: SV-64353r1_rule Severity: low CCI: CCI-000366

Discussion

Changing the root home directory to something other than / and assigning it a 0700 protection makes it more difficult for intruders to manipulate the system by reading the files root places in its default directory. It also gives root the same discretionary access control for root's home directory as for the other user home directories.System Administrator

Checks

Determine if root is assigned a home directory other than / by listing its home directory.

Procedure:
# awk -F: '($1 == "root") { print $6 }' /etc/passwd

If the root user home directory is /, this is a finding.

Fix

The root home directory should be something other than / (such as /roothome).

Procedure:
# mkdir /rootdir
# chown root /rootdir
# chgrp root /rootdir
# chmod 700 /rootdir
# cp -r /.??* /rootdir/.

Then, edit the passwd file and change the root home directory to /rootdir. The cp -r /.??* command copies all files and subdirectories of file names beginning with "." into the new root directory, which preserves the previous root environment. Ensure you are in the "/" directory when executing the "cp" command.
V-775 No Change
Findings ID: GEN000920 Rule ID: SV-64359r2_rule Severity: medium CCI: CCI-000225

Discussion

Permissions greater than 0700 could allow unauthorized users access to the root home directory.System Administrator

Checks

Check the mode of the root home directory.

Procedure:
# find ~root -type d -prune -exec ls -ld {} \;

If the home directory is /, this check will be marked "Not Applicable".

If the mode of the directory is not set to 0700 or less permissive, this is a finding.

Fix

The root home directory will be configured to have permission set of 0700 or less permissive. Do not change the protections of the / directory. Use the following command to change protections for the root home directory:

# chmod 0700 /rootdir.
V-776 No Change
Findings ID: GEN000940 Rule ID: SV-64373r4_rule Severity: medium CCI: CCI-000366

Discussion

The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Entries starting with a slash (/) are absolute paths.System Administrator

Checks

To view the root user's PATH, log in as the root user, and execute:

# env | grep PATH

This variable is formatted as a colon-separated list of directories.
Relative path entries must be document with the ISSO.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the root user's local initialization files ~/.profile,~/.bashrc (assuming root shell is bash).

Remove any relative path entries that have not been documented with the ISSO.

Remove any empty path entries that are defined in these files.
V-777 No Change
Findings ID: GEN000960 Rule ID: SV-64387r1_rule Severity: medium CCI: CCI-000366

Discussion

If the root search path contains a world-writable directory, malicious software could be placed in the path by intruders and/or malicious users and inadvertently run by root with all of root's privileges.
System Administrator

Checks

Check for world-writable permissions on all directories in the root user's executable search path.

Procedure:
# ls -ld `echo $PATH | sed "s/:/ /g"`

If any of the directories in the PATH variable are world-writable, this is a finding.

Fix

For each world-writable path in root's executable search path, do one of the following:

1. Remove the world-writable permission on the directory.
Procedure:
# chmod o-w <path>

2. Remove the world-writable directory from the executable search path.

Procedure:
Identify and edit the initialization file referencing the world-writable directory and remove it from the PATH variable.
V-778 No Change
Findings ID: GEN000980 Rule ID: SV-64389r1_rule Severity: medium CCI: CCI-000770

Discussion

Limiting the root account direct logins to only system consoles protects the root account from direct unauthorized access from a non-console device.System Administrator

Checks

Check /etc/securetty
# more /etc/securetty
If the file does not exist, or contains more than "console" or a single "tty" device this is a finding.

Fix

Create if needed and set the contents of /etc/securetty to a "console" or "tty" device.
# echo console > /etc/securetty
or
# echo tty1 > /etc/securetty
V-780 No Change
Findings ID: GEN000360 Rule ID: SV-63299r1_rule Severity: medium CCI: CCI-000366

Discussion

Reserved GIDs are typically used by system software packages. If non-system groups have GIDs in this range, they may conflict with system software, possibly leading to the group having permissions to modify system files.System Administrator

Checks

Confirm all accounts with a GID of 499 and below are used by a system account.

Procedure:
List all the users with a GID of 0-499.
# cut -d: -f 1,4 /etc/passwd|egrep ":[1-4][0-9]{2}$|:[0-9]{1,2}$"

If a GID reserved for system accounts (0 - 499) is used by a non-system account, this is a finding.

Fix

Change the primary group GID numbers for non-system accounts with reserved primary group GIDs (those less or equal to 499).
V-781 No Change
Findings ID: GEN000380 Rule ID: SV-63319r1_rule Severity: low CCI: CCI-000366

Discussion

If a user is assigned the GID of a group not existing on the system, and a group with the GID is subsequently created, the user may have unintended rights to the group.
System Administrator

Checks

Perform the following to ensure there are no GIDs referenced in /etc/passwd not defined in /etc/group:
# pwck -r
If GIDs referenced in /etc/passwd are not defined in /etc/group are returned, this is a finding.

Fix

Add a group to the system for each GID referenced without a corresponding group.
V-782 No Change
Findings ID: GEN006480 Rule ID: SV-63733r2_rule Severity: medium CCI: CCI-001259

Discussion

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.System Administrator

Checks

Ask the SA or ISSO if a host-based intrusion detection application is loaded on the system. Per OPORD 16-0080 the preferred intrusion detection system is McAfee HBSS available through Cybercom. If another host-based intrusion detection application is in use, such as SELinux, this must be documented and approved by the local Authorizing Official.

Procedure:

Examine the system to see if the Host Intrusion Prevention System (HIPS) is installed

# rpm -qa | grep MFEhiplsm

Verify that the McAfee HIPS module is active on the system.

# ps -ef | grep -i “hipclient”

If the MFEhiplsm package is not installed, check for another intrusion detection system:

# find / -name <daemon name>

Where <daemon name> is the name of the primary application daemon to determine if the application is loaded on the system.

Determine if the application is active on the system.

# ps -ef | grep -i <daemon name>

If the MFEhiplsm package is not installed and an alternate host-based intrusion detection application has not been documented for use, this is a finding.

If no host-based intrusion detection system is installed and running on the system, this is a finding.

Fix

Install and enable the latest McAfee HIPS package, available from Cybercom.

If the system does not support the McAfee HIPS package, install and enable a supported intrusion detection system application and document its use with the Authorizing Official.
V-783 No Change
Findings ID: GEN000120 Rule ID: SV-63099r1_rule Severity: medium CCI: CCI-001227

Discussion

Timely patching is critical for maintaining the operational availability, confidentiality, and integrity of information technology (IT) systems. However, failure to keep operating system and application software patched is a common mistake made by IT professionals. New patches are released daily, and it is often difficult for even experienced system administrators to keep abreast of all the new patches. When new weaknesses in an operating system exist, patches are usually made available by the vendor to resolve the problems. If the most recent security patches and updates are not installed, unauthorized users may take advantage of weaknesses present in the unpatched software. The lack of prompt attention to patching could result in a system compromise.System Administrator

Checks

Obtain the list of available package security updates from the operating system vendor. Check the available package security updates have been installed on the system.

Use the "rpm" command to list the packages installed on the system.
Example:
# rpm -qa -last

If updated packages are available and applicable to the system and have not been installed, this is a finding.

For more information, see: (1) http://linux.oracle.com/errata/ and (2) http://linux.oracle.com/cve/.

Fix

Install the patches or updated packages available from the vendor.
V-784 No Change
Findings ID: GEN001140 Rule ID: SV-64461r1_rule Severity: medium CCI: CCI-000225

Discussion

Discretionary access control is undermined if users, other than a file owner, have greater access permissions to system files and directories than the owner.System Administrator

Checks

Check system directories for uneven file permissions.

Procedure:
# ls -lL /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin

Uneven file permissions exist if the file owner has less permissions than the group or other user classes. If any of the files in the above listed directories contain uneven file permissions, this is a finding.

Fix

Change the mode of files with uneven permissions so owners do not have less permission than group or world users.
V-785 No Change
Findings ID: GEN001160 Rule ID: SV-64463r2_rule Severity: medium CCI: CCI-000366

Discussion

Un-owned files and directories may be unintentionally inherited if a user is assigned the same UID as the UID of the un-owned files.System Administrator

Checks

Check the system for files with no assigned owner.

Procedure:
# find / -ignore_readdir_race -nouser

If any files have no assigned owner, this is a finding.

Caution should be used when centralized authorization is used because valid files may appear as unowned due to communication issues.

Fix

All directories and files (executable and data) will have an identifiable owner and group name. Either trace files to an authorized user, change the file's owner to root, or delete them. Determine the legitimate owner of the files and use the chown command to set the owner and group to the correct value. If the legitimate owner cannot be determined, change the owner to root (but make sure none of the changed files remain executable because they could be Trojan horses or other malicious code). Examine the files to determine their origin and the reason for their lack of an owner/group.
V-786 No Change
Findings ID: GEN001180 Rule ID: SV-64467r1_rule Severity: medium CCI: CCI-000225

Discussion

Restricting permission on daemons will protect them from unauthorized modification and possible system compromise.System Administrator

Checks

Check the mode of network services daemons.
# find /usr/sbin -type f -perm +022 -exec stat -c %a:%n {} \;

This will return the octal permissions and name of all files that are group or world writable.
If any network services daemon listed is world or group writable (either or both of the 2 lowest order digits contain a 2, 3 or 6), this is a finding.
Note: Network daemons not residing in these directories (such as httpd or sshd) must also be checked for the correct permissions.

Fix

Change the mode of the network services daemon.
# chmod go-w <path>
V-787 No Change
Findings ID: GEN001260 Rule ID: SV-64487r3_rule Severity: medium CCI: CCI-001314

Discussion

If the system log files are not protected, unauthorized users could change the logged data, eliminating its forensic value.System Administrator

Checks

Check the mode of log files.

Procedure:
# find /var/log /var/log/syslog /var/adm -type f -perm -640 \! -perm 640

With the exception of /var/log/wtmp, /var/log/Xorg.0.log, and /var/log/gdm/:0.log, if any of the log files have modes more permissive than 0640, this is a finding.

Fix

Change the mode of the system log file(s) to 0640 or less permissive.

Procedure:
# chmod 0640 /path/to/system-log-file

Note: Do not confuse system log files with audit logs.
V-788 No Change
Findings ID: GEN001800 Rule ID: SV-63879r1_rule Severity: medium CCI: CCI-000225

Discussion

If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files.

System Administrator

Checks

Check skeleton files permissions.
# ls -alL /etc/skel
If a skeleton file has a mode more permissive than 0644, this is a finding.

Fix

Change the mode of skeleton files with incorrect mode:
# chmod 0644 <skeleton file>
V-789 No Change
Findings ID: GEN001320 Rule ID: SV-64537r1_rule Severity: medium CCI: CCI-000225

Discussion

NIS/NIS+/yp files are part of the system's identification and authentication processes and are critical to system security. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Perform the following to check NIS file ownership:
# ls -la /var/yp/*;
If the file ownership is not root, sys, or bin, this is a finding.

Fix

Change the ownership of NIS/NIS+/yp files to root, sys or bin.

Procedure (example):
# chown root <filename>
V-790 No Change
Findings ID: GEN001340 Rule ID: SV-64515r1_rule Severity: medium CCI: CCI-000225

Discussion

NIS/NIS+/yp files are part of the system's identification and authentication processes and are, therefore, critical to system security. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Perform the following to check NIS file group ownership:

# ls -la /var/yp/*

If the file group ownership is not root, sys, or bin, this is a finding.

Fix

Perform the following to change NIS file ownership.

# chgrp root /var/yp/*
V-791 No Change
Findings ID: GEN001360 Rule ID: SV-64509r1_rule Severity: medium CCI: CCI-000225

Discussion

NIS/NIS+/yp files are part of the system's identification and authentication processes and are critical to system security. Unauthorized modification of these files could compromise these processes and the system.System Administrator

Checks

Perform the following to check NIS file permissions.

# ls -la /var/yp/*

If the file's mode is more permissive than 0755, this is a finding.

Fix

Change the mode of NIS/NIS+/yp command files to 0755 or less permissive.

Procedure (example):
# chmod 0755 <filename>
V-792 No Change
Findings ID: GEN001280 Rule ID: SV-64517r3_rule Severity: low CCI: CCI-000225

Discussion

If manual pages are compromised, misleading information could be inserted, causing actions to compromise the system.System Administrator

Checks

Check the mode of the manual page files.

Procedure:

# find /usr/share/man /usr/share/info /usr/share/infopage -type f -perm +022 -exec stat -c %a:%n {} \; |> more

Note: This list only displays manual files with offending permissions.

If any of the manual page files have a mode more permissive than 0644, this is a finding.

Fix

Change the mode of manual page files to 0644 or less permissive.

Procedure (example):
# chmod 0644 /path/to/manpage
V-793 No Change
Findings ID: GEN001300 Rule ID: SV-64525r2_rule Severity: medium CCI: CCI-001499

Discussion

Unauthorized access could destroy the integrity of the library files.System Administrator

Checks

Check the mode of library files.

Procedure:
# DIRS="/usr/lib /lib /usr/lib64 /lib64";for DIR in $DIRS;do find $DIR -type f -perm +022 -exec stat -c %a:%n {} \;;done

This will return the octal permissions and name of all group or world writable files.
If any file listed is world or group writable (either or both of the 2 lowest order digits contain a 2, 3 or 6), this is a finding.

Fix

Change the mode of library files to 0755 or less permissive.

Procedure (example):
# chmod go-w </path/to/library-file>

Note: Library files should have an extension of ".a" or a ".so" extension, possibly followed by a version number.
V-794 No Change
Findings ID: GEN001200 Rule ID: SV-64477r2_rule Severity: medium CCI: CCI-001499

Discussion

Restricting permissions will protect system command files from unauthorized modification. System command files include files present in directories used by the operating system for storing default system executables and files present in directories included in the system's default executable search paths.Elevate to Severity Code I if any file listed world-writable.System Administrator

Checks

Check the permissions for files in /etc, /bin, /usr/bin, /usr/lbin, /usr/ucb, /sbin, and /usr/sbin.

Procedure:
# DIRS="/etc /bin /usr/bin /usr/lbin /usr/ucb /sbin /usr/sbin";for DIR in $DIRS;do find $DIR -type f -perm +022 -exec stat -c %a:%n {} \;;done

This will return the octal permissions and name of all group or world writable files. If any command file is listed and is world or group writable (either or both of the 2 lowest order digits contain a 2, 3 or 6), this is a finding.

Note: Elevate to Severity Code I if any command file listed is world writable.

Fix

Change the mode for system command files to 0755 or less permissive taking into account necessary GIUD and SUID bits.

Procedure:
# chmod go-w <filename>
V-795 No Change
Findings ID: GEN001220 Rule ID: SV-64483r1_rule Severity: medium CCI: CCI-001499

Discussion

Restricting permissions will protect the files from unauthorized modification.System Administrator

Checks

Check the ownership of system files, programs, and directories.

Procedure:
# ls -lLa /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin

If any of the system files, programs, or directories are not owned by a system account, this is a finding.

Fix

Change the owner of system files, programs, and directories to a system account.

Procedure:
# chown root /some/system/file

(A different system user may be used in place of root.)
V-796 No Change
Findings ID: GEN001240 Rule ID: SV-64485r1_rule Severity: medium CCI: CCI-001499

Discussion

Restricting permissions will protect the files from unauthorized modification.System Administrator

Checks

Check the group-ownership of system files, programs, and directories.

Procedure:
# ls -lLa /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin

If any system file, program, or directory is not owned by a system group, this is a finding.

Fix

Change the group-owner of system files to a system group.

Procedure:
# chgrp root /path/to/system/file

(System groups other than root may be used.)
V-797 No Change
Findings ID: GEN001400 Rule ID: SV-64569r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Check the ownership of the /etc/shadow file.

# ls -lL /etc/shadow

If the /etc/shadow file is not owned by root, this is a finding.

Fix

Change the ownership of the /etc/shadow (or equivalent) file.

# chown root /etc/shadow
V-798 No Change
Findings ID: GEN001380 Rule ID: SV-64557r1_rule Severity: medium CCI: CCI-000225

Discussion

If the passwd file is writable by a group-owner or the world, the risk of passwd file compromise is increased. The passwd file contains the list of accounts on the system and associated information.System Administrator

Checks

Check the mode of the /etc/passwd file.

Procedure:
# ls -lL /etc/passwd

If /etc/passwd has a mode more permissive than 0644, this is a finding.

Fix

Change the mode of the passwd file to 0644.

Procedure:
# chmod 0644 /etc/passwd
V-800 No Change
Findings ID: GEN001420 Rule ID: SV-64573r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root.System Administrator

Checks

Check the mode of the /etc/shadow file.

# ls -lL /etc/shadow

If the /etc/shadow file has a mode more permissive than 0400, this is a finding.

Fix

Change the mode of the /etc/shadow (or equivalent) file.

# chmod 0400 /etc/shadow
V-801 No Change
Findings ID: GEN002380 Rule ID: SV-63399r4_rule Severity: medium CCI: CCI-000368

Discussion

All files with the setuid bit set will allow anyone running these files to be temporarily assigned the UID of the file. While many system files depend on these attributes for proper operation, security problems can result if setuid is assigned to programs allowing reading and writing of files, or shell escapes. Only default vendor-supplied executables should have the setuid bit set.System AdministratorInformation Assurance Officer

Checks

Check for the presence of aide on the system:
# rpm -qa | grep aide

If aide is not installed, ask the SA what file integrity tool is being used to check the system.

Check the global crontabs for the presence of an "aide" job to run at least weekly, if aide is installed. Otherwise, check for the presence of a cron job to run the alternate file integrity checking application.

# grep aide /etc/cron*/*

If a tool is being run, then the configuration file for the appropriate tool needs to be checked for selection lines /bin, /sbin, /lib, and /usr.

If the file integrity tool is set to check setuid and setgid, this is not a finding.

List all setuid files on the system.
Procedure:
# find / -perm -4000 -exec ls -l {} \; | more

Note: Executing these commands may result in large listings of files; the output may be redirected to a file for easier analysis.

Ask the SA or ISSO if files with the setuid bit set have been documented. Documentation must include the owner, group-owner, mode, ACL, and location of the files.

If any undocumented file has its setuid bit set, this is a finding.

Fix

Document the files with the suid bit set or unset the suid bit on the executable.
V-802 No Change
Findings ID: GEN002440 Rule ID: SV-63459r2_rule Severity: medium CCI: CCI-000368

Discussion

All files with the setgid bit set will allow anyone running these files to be temporarily assigned the GID of the file. While many system files depend on these attributes for proper operation, security problems can result if setgid is assigned to programs allowing reading and writing of files, or shell escapes.trueSystem AdministratorInformation Assurance Officer

Checks

If STIGID GEN000220 is satisfied, this is not a finding.

List all setgid files on the system.
Procedure:

# find / -perm -2000 -exec ls -l {} \; | more

Note: Executing these commands may result in large listings of files; the output may be redirected to a file for easier analysis.

Ask the SA or IAO if files with the setgid bit set have been documented. Documentation must include owner, group-owner, mode, ACL, and location.

If any undocumented file has its setgid bit set, this is a finding.

If a tool is being run then the configuration file for the appropriate tool needs to be checked for selection lines /bin, /sbin, /lib, and /usr.

If a file integrity tool is set to check setuid and setgid, this is not a finding.

Fix

Document the files with the sgid bit set or unset the sgid bit on the executable.
V-803 No Change
Findings ID: GEN002400 Rule ID: SV-63421r3_rule Severity: medium CCI: CCI-000318

Discussion

Files with the setuid bit set will allow anyone running these files to be temporarily assigned the UID of the file. While many system files depend on these attributes for proper operation, security problems can result if setuid is assigned to programs allowing reading and writing of files, or shell escapes.System Administrator

Checks

Ask the SA for the weekly automated or manual process used to generate a list of setuid files on the system and compare it with the prior list.

If no such process is in place, this is a finding.

If a file integrity tool is configured to monitor setuid files weekly, this is not a finding.

Review the process.

If the process does not identify and report changes in setuid files, this is a finding.

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.

Fix

Establish a weekly automated or manual process to generate a list of suid files on the system and compare it with the prior list.

To create a list of suid files:

# find / -perm -4000 > suid-file-list

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.
V-804 No Change
Findings ID: GEN002460 Rule ID: SV-63589r3_rule Severity: medium CCI: CCI-000318

Discussion

Files with the setgid bit set will allow anyone running these files to be temporarily assigned the group id of the file. While many system files depend on these attributes for proper operation, security problems can result if setgid is assigned to programs allowing reading and writing of files, or shell escapes.System Administrator

Checks

Ask the SA if a weekly automated or manual process is used to generate a list of setgid files on the system and compare it with the prior list.

If no such process is in place, this is a finding.

If a file integrity tool is configured to monitor setgid files weekly, this is not a finding.

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.

Fix

Establish a weekly automated or manual process to generate a list of setgid files on the system and compare it with the prior list.

To create a list of setgid files:

# find / -perm -2000 > setgid-file-list

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.
V-805 No Change
Findings ID: GEN002420 Rule ID: SV-63441r1_rule Severity: medium CCI: CCI-000225

Discussion

The "nosuid" mount option causes the system to not execute setuid files with owner privileges. This option must be used for mounting any file system not containing approved setuid files. Executing setuid files from untrusted file systems, or file systems not containing approved setuid files, increases the opportunity for unprivileged users to attain unauthorized administrative access.System AdministratorECLP-1

Checks

Check /etc/mtab and verify the "nosuid" mount option is used on file systems mounted from removable media, network shares, or any other file system not containing approved setuid or setgid files. If any of these files systems do not mount with the "nosuid" option, it is a finding.

Fix

Edit /etc/fstab and add the "nosuid" mount option to all file systems mounted from removable media or network shares, and any file system not containing approved setuid or setgid files.
V-806 No Change
Findings ID: GEN002500 Rule ID: SV-63691r1_rule Severity: low CCI: CCI-000366

Discussion

Failing to set the sticky bit on the 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, (e.g., /tmp), and for directories requiring global read/write access.System Administrator

Checks

Check all world-writable directories have the sticky bit set.

Procedure:
# find / -type d -perm -002 ! -perm -1000 > wwlist

If the sticky bit is not set on a world-writable directory, this is a finding.

Fix

Set the sticky bit on all public directories.

Procedure:
# chmod 1777 /tmp

(Replace /tmp with the public directory missing the sticky bit, if necessary.)
V-807 No Change
Findings ID: GEN002520 Rule ID: SV-63705r1_rule Severity: medium CCI: CCI-000225

Discussion

If a public directory has the sticky bit set and is not owned by a privileged UID, unauthorized users may be able to modify files created by others.

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, (e.g., /tmp), and for directories requiring global read/write access.System Administrator

Checks

Check the ownership of all public directories.

Procedure:
# find / -type d -perm -1002 -exec ls -ld {} \;

If any public directory is not owned by root or an application user, this is a finding.

Fix

Change the owner of public directories to root or an application account.

Procedure:
# chown root /tmp

(Replace root with an application user and/or /tmp with another public directory as necessary.)
V-808 No Change
Findings ID: GEN002560 Rule ID: SV-63801r1_rule Severity: medium CCI: CCI-000366

Discussion

The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask can be represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0. This requirement applies to the globally configured system defaults and the user defaults for each account on the system.trueIf the default umask is 000 or does not restrict the world-writable permission, this becomes a CAT I finding.System Administrator

Checks

NOTE: The following commands must be run in the BASH shell.

Check global initialization files for the configured umask value.
Procedure:
# grep umask /etc/*

Check local initialization files for the configured umask value.
Procedure:
# cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep umask {} \;

If the system and user default umask is not 077, this a finding.

Note: If the default umask is 000 or allows for the creation of world-writable files this becomes a Severity Code I finding.

Fix

Edit local and global initialization files that contain "umask" and change them to use 077 instead of the current value.
V-810 No Change
Findings ID: GEN002640 Rule ID: SV-63809r1_rule Severity: medium CCI: CCI-000178

Discussion

Vendor accounts and software may contain backdoors allowing unauthorized access to the system. These backdoors are common knowledge and present a threat to system security if the account is not disabled.System Administrator

Checks

Determine if default system accounts (such as those for sys, bin, uucp, nuucp, daemon, smtp) have been disabled.

# cat /etc/shadow

If an account's password field (which is the second field in the /etc/shadow file) is "*", "*LK*", or is prefixed with a '!', the account is locked or disabled.

If there are any unlocked default system accounts this is a finding.

Fix

Lock the default system account(s).
# passwd -l <user>
V-811 No Change
Findings ID: GEN002660 Rule ID: SV-63819r1_rule Severity: medium CCI: CCI-000169

Discussion

Without auditing, individual system accesses cannot be tracked and malicious activity cannot be detected and traced back to an individual account.System Administrator

Checks

Determine if auditing is enabled.
# ps -ef |grep auditd
If the auditd process is not found, this is a finding.

Fix

Start the auditd service and set it to start on boot.
# service auditd start ; chkconfig auditd on
V-812 No Change
Findings ID: GEN002680 Rule ID: SV-63845r1_rule Severity: medium CCI: CCI-000162

Discussion

Failure to give ownership of system audit log files to root provides the designated owner and unauthorized users with the potential to access sensitive information.System Administrator

Checks

Perform the following to determine the location of audit logs and then check the ownership.

Procedure:
# grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %U:%n

If any audit log file is not owned by root, this is a finding.

Fix

Change the ownership of the audit log file(s).

Procedure:
# chown root <audit log file>
V-813 No Change
Findings ID: GEN002700 Rule ID: SV-63883r1_rule Severity: medium CCI: CCI-000163

Discussion

If a user can write to the audit logs, audit trails can be modified or destroyed and system intrusion may not be detected. System audit logs are those files generated from the audit system and do not include activity, error, or other log files created by application software.System Administrator

Checks

Perform the following to determine the location of audit logs and then check the mode of the files.
Procedure:
# grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %a:%n

If any audit log file has a mode more permissive than 0640, this is a finding.

Fix

Change the mode of the audit log directories/files.
# chmod 0750 <audit directory>
# chmod 0640 <audit file>
V-814 No Change
Findings ID: GEN002720 Rule ID: SV-64247r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Verify auditd is configured to audit failed file access attempts.

There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S creat" | grep -e "-F success=0"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S creat" | grep -e "-F exit=-EPERM"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S creat" | grep -e "-F exit=-EACCES"

If an "-S creat" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "creat" exist, then this is a finding.

Fix

Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs:

either:
-a exit,always -F arch=<ARCH> -S creat -F success=0

or both:
-a exit,always -F arch=<ARCH> -S creat -F exit=-EPERM
-a exit,always -F arch=<ARCH> -S creat -F exit=-EACCES

Restart the auditd service.
# service auditd restart
V-815 No Change
Findings ID: GEN002740 Rule ID: SV-64263r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the system audit configuration to determine if file and directory deletions are audited.

# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "unlink"

If no results are returned, or the results do not contain "-S unlink", this is a finding.

Fix

The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.

Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement and are a finding unless justified and documented appropriately.

The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.

Procedure:

Edit the /etc/audit/audit.rules file, and add one or more the lines (subject to the dual-architecture discussion above) to enable auditing of deletions:

-a exit,always -F arch=<ARCH> -S unlink

Restart the auditd service:

# service auditd restart
V-818 No Change
Findings ID: GEN002800 Rule ID: SV-65285r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

The message types that are always recorded to /var/log/audit/audit.log include LOGIN,USER_LOGIN,USER_START,USER_END among others and do not need to be added to audit_rules.

The log files /var/log/faillog and /var/log/lastlog must be protected from tampering of the login records.

Procedure:
#egrep "faillog|lastlog" /etc/audit/audit.rules|grep "-p (wa|aw)"

If both /var/log/faillog and /var/log/lastlog entries do not exist, this is a finding.

Fix

Ensure logins.

Procedure:

Modify /etc/audit/audit.rules to contain:

-w /var/log/faillog -p wa
-w /var/log/lastlog -p wa

Restart the auditd service:
# service auditd restart
V-819 No Change
Findings ID: GEN002820 Rule ID: SV-64623r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
System Administrator

Checks

Check the system's audit configuration.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i " chmod "

If "-S chmod" is not in the result, this is a finding.

Fix

The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.

On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.

Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.

The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.

Procedure:
Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications.

-a exit,always -F arch=<ARCH> -S chmod

Restart the auditd service.
# service auditd restart
V-821 No Change
Findings ID: GEN003720 Rule ID: SV-64233r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of sensitive files or utilities to root provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration possibly weakening the system's security posture.System Administrator

Checks

Check the owner of the xinetd configuration files.

Procedure:
# ls -lL /etc/xinetd.conf
# ls -laL /etc/xinetd.d
This is a finding if any of the above files or directories are not owned by root or bin.

Fix

Change the owner of the xinetd configuration files.

# chown root /etc/xinetd.conf /etc/xinetd.d/*
V-822 No Change
Findings ID: GEN003740 Rule ID: SV-64239r1_rule Severity: medium CCI: CCI-000225

Discussion

The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system.System Administrator

Checks

Check the mode of the xinetd configuration files.

Procedure:
# ls -lL /etc/xinetd.conf
# ls -lL /etc/xinetd.d
If the mode of the file(s) is more permissive than 0640, this is a finding.

Fix

Change the mode of the xinetd configuration files.
# chmod 0640 /etc/xinetd.conf /etc/xinetd.d/*
V-823 No Change
Findings ID: GEN003760 Rule ID: SV-63977r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration possibly weakening the system's security posture.System Administrator

Checks

Check the ownership of the services file.

Procedure:
# ls -lL /etc/services

If the services file is not owned by root or bin, this is a finding.

Fix

Change the ownership of the services file to root or bin.

Procedure:
# chown root /etc/services
V-824 No Change
Findings ID: GEN003780 Rule ID: SV-63983r1_rule Severity: medium CCI: CCI-000225

Discussion

The services file is critical to the proper operation of network services and must be protected from unauthorized modification. Unauthorized modification could result in the failure of network services.System Administrator

Checks

Check the mode of the services file.

Procedure:
# ls -lL /etc/services

If the services file has a mode more permissive than 0644, this is a finding.

Fix

Change the mode of the services file to 0644 or less permissive.

Procedure:
# chmod 0644 /etc/services
V-825 No Change
Findings ID: GEN001780 Rule ID: SV-63875r1_rule Severity: low CCI: CCI-000366

Discussion

If the "mesg -n" or "mesg n" command is not placed into the system profile, messaging can be used to cause a Denial of Service attack.System Administrator

Checks

Check global initialization files for the presence of "mesg -n" or "mesg n".

Procedure:
# grep "mesg" etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/*

If no global initialization files contain "mesg -n" or "mesg n", this is a finding.

Fix

Edit /etc/profile or another global initialization script, and add the "mesg -n" command.
V-827 No Change
Findings ID: GEN003900 Rule ID: SV-64115r1_rule Severity: medium CCI: CCI-000366

Discussion

Having the '+' character in the hosts.lpd (or equivalent) file allows all hosts to use local system print resources.System Administrator

Checks

The operating system uses the CUPS print service. Verify remote host access is limited.

Procedure:
# grep -i Listen /etc/cups/cupsd.conf

The /etc/cups/cupsd.conf file must not contain a Listen *:<port> or equivalent line.

If the network address of the "Listen" line is unrestricted, this is a finding.

# grep -i "Allow From" /etc/cups/cupsd.conf

The "Allow From" line within the "<Location />" element should limit access to the printers to @LOCAL and specific hosts.
If the "Allow From" line contains "All" this is a finding.

Fix

Configure cups to use only the localhost or specified remote hosts.

Procedure:
Modify the /etc/cups/cupsd.conf file to "Listen" only to the local machine or a known set of hosts (i.e., Listen localhost:631).
Modify the /etc/cups/cupsd.conf file "<Location />" element to "Deny From All" and "Allow from 127.0.0.1" or allowed host addresses.

Restart cups:
# service cups restart
V-828 No Change
Findings ID: GEN003920 Rule ID: SV-64119r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of the hosts.lpd file to root, bin, sys, or lp provides the designated owner, and possible unauthorized users, with the potential to modify the hosts.lpd file. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.System Administrator

Checks

Check the ownership of the print service configuration file.

Procedure:
# ls -lL /etc/cups/printers.conf;

If no print service configuration file is found, this is not applicable.
If the owner of the file is not root, this is a finding.

Fix

Change the owner of the /etc/cups/printers.conf to root.

Procedure:
# chown root /etc/cups/printers.conf
V-829 No Change
Findings ID: GEN003940 Rule ID: SV-64121r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the hosts.lpd (or equivalent) file may permit unauthorized modification. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.System Administrator

Checks

Check the mode of the print service configuration file.

Procedure:
# ls -lL /etc/cups/printers.conf

If no print service configuration file is found, this is not applicable.
If the mode of the print service configuration file is more permissive than 0664, this is a finding.

Fix

Change the mode of the /etc/cups/printers.conf file to 0664 or less permissive.

Procedure:
# chmod 0664 /etc/cups/printers.conf
V-831 No Change
Findings ID: GEN004360 Rule ID: SV-63607r1_rule Severity: medium CCI: CCI-000225

Discussion

If the alias file is not owned by root, an unauthorized user may modify the file adding aliases to run malicious code or redirect e-mail.System Administrator

Checks

If the "sendmail" and "postfix" packages are not installed, this is not applicable.

Check the ownership of the alias files.

Procedure:
for sendmail:
# ls -lL /etc/aliases
# ls -lL /etc/aliases.db
If all the files are not owned by root, this is a finding.

for postfix:
Verify the location of the alias file.
# postconf alias maps

This will return the location of the "aliases" file, by default "/etc/postfix/aliases"

# ls -lL <postfix aliases file>
# ls -lL <postfix aliases.db file>
If all the files are not owned by root, this is a finding.

Fix

Change the owner of the /etc/aliases file to root.

Procedure:
for sendmail:
# chown root /etc/aliases
# chown root /etc/aliases.db

for postfix
# chown root /etc/postfix/aliases
# chown root /etc/postfix/aliases.db
V-832 No Change
Findings ID: GEN004380 Rule ID: SV-63637r2_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect e-mail.System Administrator

Checks

If the "sendmail" and "postfix" packages are not installed, this is not applicable.

Check the permissions of the alias file.

Procedure:
for sendmail:

# ls -lL /etc/aliases /etc/aliases.db

If an alias file has a mode more permissive than 0644, this is a finding.

for postfix:
Verify the location of the alias file.

# postconf alias_maps

This will return the location of the "aliases" file, by default "/etc/postfix/aliases".

# ls -lL <postfix aliases file> <postfix aliases.db file>

If an alias file has a mode more permissive than 0644, this is a finding.

Fix

Change the mode of the alias files as needed to function.

No higher than 0644.

Procedure:
for sendmail:

# chmod 0644 /etc/aliases /etc/aliases.db

for postfix (assuming the default postfix directory):
# chmod 0644 /etc/postfix/aliases /etc/postfix/aliases
V-833 No Change
Findings ID: GEN004400 Rule ID: SV-63699r1_rule Severity: high CCI: CCI-000225

Discussion

If a file executed through a mail aliases file is not owned and writable only by root, it may be subject to unauthorized modification. Unauthorized modification of files executed through aliases may allow unauthorized users to attain root privileges.System Administrator

Checks

Verify the ownership of files referenced within the sendmail aliases file.

Procedure:
# more /etc/aliases
Examine the aliases file for any utilized directories or paths.

# ls -lL <directory or file path>

Check the owner for any paths referenced.

Check if the file or parent directory is owned by root. If not, this is a finding.

Fix

Edit the /etc/aliases file (alternatively, /usr/lib/sendmail.cf). Locate the entries executing a program. They will appear similar to the following line:

Aliasname: : /usr/local/bin/ls (or some other program name)

Ensure root owns the programs and the directory(ies) they reside in by using the chown command to change owner to root.

Procedure:
# chown root <file or directory name>
V-834 No Change
Findings ID: GEN004420 Rule ID: SV-63739r1_rule Severity: medium CCI: CCI-000225

Discussion

If a file executed through a mail aliases file has permissions greater than 0755, it can be modified by an unauthorized user and may contain malicious code or instructions potentially compromising the system.System Administrator

Checks

If the "sendmail" package is not installed, this is not applicable.

Examine the contents of the /etc/aliases file.

Procedure:
# more /etc/aliases
Examine the aliases file for any referenced programs, which are specified with the pipe (|) symbol.

# ls -lL <file referenced from aliases>

Check the permissions for any paths referenced.

If any file referenced from the aliases file has a mode more permissive than 0755, this is a finding.

Fix

Use the chmod command to change the access permissions for files executed from the alias file.

For example:
# chmod 0755 filename
V-835 No Change
Findings ID: GEN004440 Rule ID: SV-63747r1_rule Severity: low CCI: CCI-000366

Discussion

If Sendmail is not configured to log at level 9, system logs may not contain the information necessary for tracking unauthorized use of the sendmail service.System Administrator

Checks

If the "sendmail" package is not installed, this is not applicable.

Check if sendmail logging is set to level nine:

Procedure:
for sendmail:
# grep "O L" /etc/mail/sendmail.cf

OR

# grep LogLevel /etc/mail/sendmail.cf

If logging is set to less than nine, this is a finding.

for Postfix:
This rule is not applicable to postfix which does not use "log levels" in the same fashion as sendmail.

Fix

Edit the sendmail.cf file, locate the "O L" or "LogLevel" entry and change it to 9.
V-836 No Change
Findings ID: GEN004460 Rule ID: SV-63749r2_rule Severity: medium CCI: CCI-000126

Discussion

If informational and more severe SMTP service messages are not logged, malicious activity on the system may go unnoticed.System Administrator

Checks

Check the syslog configuration file for mail.crit logging configuration. Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Procedure:

# grep "mail\." /etc/syslog.conf

Or:

#grep "mail\." /etc/syslog.conf

If syslog is not configured to log critical sendmail messages ("mail.crit" or "mail.*"), this is a finding.

Fix

Edit the syslog.conf or rsyslog.conf file and add a configuration line specifying an appropriate destination for "mail.crit" or "mail.*" syslog messages.
V-837 No Change
Findings ID: GEN004480 Rule ID: SV-63751r3_rule Severity: medium CCI: CCI-000225

Discussion

If the SMTP service log file is not owned by root, then unauthorized personnel may modify or delete the file to hide a system compromise.System Administrator

Checks

Locate any mail log files by checking the syslog configuration file.

Procedure:

The check procedure is the same for both sendmail and Postfix.

Identify any log files configured for the "mail" service (excluding mail.none) at any severity level and check the ownership. Depending on what system is used for log processing, either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

For syslog:

# egrep "mail\.[^n][^/]*" /etc/syslog.conf|sed 's/^[^/]*//'|xargs ls -lL

For rsyslog:

# egrep "mail\.[^n][^/]*" /etc/rsyslog.conf|sed 's/^[^/]*//'|xargs ls -lL

If any mail log file is not owned by root, this is a finding.

Fix

Change the ownership of the sendmail log file.

Procedure:

The fix procedure is the same for both sendmail and Postfix.

# chown root <sendmail log file>
V-838 No Change
Findings ID: GEN004500 Rule ID: SV-63753r3_rule Severity: medium CCI: CCI-000225

Discussion

If the SMTP service log file is more permissive than 0644, unauthorized users may be allowed to change the log file.System Administrator

Checks

Check the mode of the SMTP service log file.

Procedure:

The check procedure is the same for both sendmail and Postfix.

Identify any log files configured for the "mail" service (excluding mail.none) at any severity level and check the permissions. Depending on what system is used for log processing, either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

For syslog:

# egrep "mail\.[^n][^/]*" /etc/syslog.conf|sed 's/^[^/]*//'|xargs ls -lL

For rsyslog:

# egrep "mail\.[^n][^/]*" /etc/rsyslog.conf|sed 's/^[^/]*//'|xargs ls -lL

If the log file permissions are greater than 0644, this is a finding.

Fix

Change the mode of the SMTP service log file.

Procedure:

The fix procedure is the same for both sendmail and Postfix.

# chmod 0644 <sendmail log file>
V-840 No Change
Findings ID: GEN004880 Rule ID: SV-62959r1_rule Severity: medium CCI: CCI-000225

Discussion

The ftpusers file contains a list of accounts not allowed to use FTP to transfer files. If this file does not exist, then unauthorized accounts can utilize FTP.System Administrator

Checks

Check for the existence of the ftpusers file.

Procedure:
For gssftp:
# ls -l /etc/ftpusers

For vsftp:
# ls -l /etc/vsftpd.ftpusers
or
# ls -l /etc/vsftpd/ftpusers

If the appropriate ftpusers file for the running FTP service does not exist, this is a finding.

Fix

Create an ftpusers file appropriate for the running FTP service.

For gssftp:
Create an /etc/ftpusers file containing a list of accounts not authorized for FTP.

For vsftp:
Create an /etc/vsftpd.ftpusers or /etc/vsftpd/ftpusers (as appropriate) file containing a list of accounts not authorized for FTP.
V-841 No Change
Findings ID: GEN004900 Rule ID: SV-62981r1_rule Severity: medium CCI: CCI-000225

Discussion

The ftpusers file contains a list of accounts not allowed to use FTP to transfer files. If the file does not contain the names of all accounts not authorized to use FTP, then unauthorized use of FTP may take place.System Administrator

Checks

Check the contents of the ftpusers file.
For gssftp:
# more /etc/ftpusers

For vsftp:
# more /etc/vsftpd.ftpusers /etc/vfsftpd/ftpusers
If the system has accounts not allowed to use FTP and not listed in the ftpusers file, this is a finding.

Fix

For gssftp:
Add accounts not allowed to use FTP to the /etc/ftpusers file.

For vsftp:
Add accounts not allowed to use FTP to the /etc/vsftpd.ftpusers or /etc/vsftpd/ftpusers file (as appropriate).
V-842 No Change
Findings ID: GEN004920 Rule ID: SV-63009r1_rule Severity: medium CCI: CCI-000225

Discussion

If the file ftpusers is not owned by root, an unauthorized user may modify the file to allow unauthorized accounts to use FTP.System Administrator

Checks

Check the ownership of the ftpusers file.

Procedure:
For gssftp:
# ls -l /etc/ftpusers

For vsftp:
# ls -l /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers

If the ftpusers file is not owned by root, this is a finding.

Fix

Change the owner of the ftpusers file to root.
For gssftp:
# chown root /etc/ftpusers

For vsftp:
# chown root /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers
V-843 No Change
Findings ID: GEN004940 Rule ID: SV-63079r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service.System Administrator

Checks

Check the permissions of the ftpusers file.

Procedure:
For gssftp:
# ls -l /etc/ftpusers

For vsftp:
# ls -l /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers

If the ftpusers file has a mode more permissive than 0640, this is a finding.

Fix

Change the mode of the ftpusers file to 0640.

Procedure:
For gssftp:
# chmod 0640 /etc/ftpusers

For vsftp:
# chmod 0640 /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers
V-845 No Change
Findings ID: GEN004980 Rule ID: SV-63103r1_rule Severity: low CCI: CCI-000130

Discussion

The -l option allows basic logging of connections. The verbose (on HP) and the debug (on Solaris) allow logging of what files the ftp session transferred. This extra logging makes it possible to easily track which files are being transferred onto or from a system. If they are not configured, the only option for tracking is the audit files. The audit files are much harder to read. If auditing is not properly configured, then there would be no record at all of the file transfer transactions.System Administrator

Checks

Find if logging is applied to the ftp daemon. The procedure depends on the implementation of ftpd used by the system.

Procedures:
For vsftpd:
If vsftpd is started by xinetd:

#grep vsftpd /etc/xinetd.d/*
This will indicate the xinetd.d startup file

#grep server_args <vsftpd xinetd.d startup file>
This will indicate the vsftpd config file used when starting through xinetd.

If the line is missing then "/etc/vsftpd/vsftpd.conf", the default config file, is used.

#grep xferlog_enable <vsftpd config file>
If "xferlog_enable" is missing or is not set to "yes", this is a finding.

If vsftp is not started by xinetd:
#grep xferlog_enable /etc/vsftpd/vsftpd.conf
If "xferlog_enable" is missing or is not set to "yes", this is a finding.

For gssftp:
Find if the -l option will be applied when xinetd starts gssftp

# grep server_args /etc/xinetd.d/gssftp

If the line is missing or does not contain at least one -l, this is a finding.

Fix

Enable logging by changing ftpd startup or config files.

Procedure:
The procedure depends on the implementation of ftpd used by the system.

For vsftpd:

Ensure the server settings in "/etc/vsftpd.conf" (or other configuration file specified by the vaftpd xinetd.d startup file) contains:

xferlog_enable = yes

For gssftp:
If the "disable" server setting is missing or set to "no" in "/etc/xinetd.d/gssftp" then
ensure the server settings in "/etc/xinetd.d/gssftp" contains:

server_args = -l

The -l option may be added up to three times. Each -l will provide increasing verbosity on the log. Refer to the main page for ftpd for more information.

For both if started using xinetd:
If the "disable" server setting is missing or set to "no" in the /etc/xinetd.d startup file then
ensure the server settings contains:

log_on_success += DURATION USERID
This will log the startup and shutdown of the daemon.

log_on_failure += HOST USERID
V-846 No Change
Findings ID: GEN004820 Rule ID: SV-62955r1_rule Severity: medium CCI: CCI-001475

Discussion

Due to the numerous vulnerabilities inherent in anonymous FTP, it is not recommended. If anonymous FTP must be used on a system, the requirement must be authorized and approved in the system accreditation package.trueSystem AdministratorInformation Assurance Officer

Checks

Attempt to log into this host with a user name of anonymous and a password of guest (also try the password of [email protected]). If the logon is successful and the use of anonymous ftp has not been documented and approved by the IAO, this is a finding.

Procedure:
# ftp localhost
Name: anonymous
530 Guest login not allowed on this machine.

Fix

Configure the FTP service to not permit anonymous logins.
V-847 No Change
Findings ID: GEN005080 Rule ID: SV-63119r1_rule Severity: high CCI: CCI-000366

Discussion

Secure mode limits TFTP requests to a specific directory. If TFTP is not running in secure mode, it may be able to write to any file or directory and may seriously impair system integrity, confidentiality, and availability.System Administrator

Checks

# grep server_args /etc/xinetd.d/tftp
If the "-s" parameter is not specified, this is a finding.

Fix

Edit /etc/xinetd.d/tftp file and specify the "-s" parameter in server_args.
V-848 No Change
Findings ID: GEN005100 Rule ID: SV-63163r1_rule Severity: high CCI: CCI-000225

Discussion

If TFTP runs with the setuid or setgid bit set, it may be able to write to any file or directory and may seriously impair system integrity, confidentiality, and availability.System Administrator

Checks

Check the mode of the TFTP daemon.

Procedure:
# grep "server " /etc/xinetd.d/tftp
# ls -lL <in.tftpd binary>

If the mode of the file is more permissive than 0755, this is a finding.

Fix

Change the mode of the TFTP daemon.

Procedure:
# chmod 0755 <in.tftpd binary>
V-849 No Change
Findings ID: GEN005120 Rule ID: SV-63159r1_rule Severity: medium CCI: CCI-000225

Discussion

If TFTP has a valid shell, it increases the likelihood someone could log on to the TFTP account and compromise the system.System Administrator

Checks

Check the /etc/passwd file to determine if TFTP is configured properly.

Procedure:
Check if TFTP if used.
# grep disable /etc/xinetd.d/tftp

If the file does not exist or the returned line indicates "yes", then this is not a finding.

Otherwise, if the returned line indicates "no" then TFTP is enabled and must use a dedicated "tftp" user.

# grep user /etc/xinetd.d/tftp

If the returned line indicates a user other than the dedicated "tftp" user, this is a finding.

# grep tftp /etc/passwd

If a "tftp" user account does not exist and TFTP is active, this is a finding.

Check the user shell for the "tftp" user. If it is not /bin/false or equivalent, this is a finding.

Check the home directory assigned to the "tftp" user. If no home directory is set, or the directory specified is not dedicated to the use of the TFTP service, this is a finding.

Fix

Configure TFTP to use a dedicated "tftp" user.

Procedure:
Create a dedicated "tftp" user account if none exists.

Assign a non-login shell to the "tftp" user account, such as /bin/false.

Assign a home directory to the "tftp" user account.

Edit /etc/xinetd.d/tftp to have "tftp" as the value of the "user" parameter.
V-850 No Change
Findings ID: GEN005160 Rule ID: SV-63199r3_rule Severity: medium CCI: CCI-000297

Discussion

.Xauthority files ensure the user is authorized to access specific X Windows host. If .Xauthority files are not used, it may be possible to obtain unauthorized access to the X Windows host.System Administrator

Checks

Check for .Xauthority or .xauth files being utilized by looking for such files in the home directory of a user.

Procedure:

# find / -name '.xauth*' | more

If no .xauth files are found in a user's home directory, ensure that Xwindows is not active on the system by performing the command:

# ps -ef | grep X

If Xwindows is not running, this rule is not applicable.

If the .Xauthority or .xauth (followed by apparently random characters) files do not exist, ask the SA if the user is using Xwindows.

If the user is utilizing Xwindows and none of these files exist, this is a finding.

Fix

Ensure the X Windows host is configured to write .Xauthority files into user home directories.

Edit the Xaccess file.

Ensure the line writing the .Xauthority file is uncommented.
V-867 No Change
Findings ID: GEN006400 Rule ID: SV-63803r1_rule Severity: medium CCI: CCI-001435

Discussion

Due to numerous security vulnerabilities existing within NIS, it must not be used. Possible alternative directory services are NIS+ and LDAP.System AdministratorInformation Assurance Officer

Checks

Perform the following to determine if NIS is active on the system:

# ps -ef | grep ypbind

If NIS is found active on the system, this is a finding.

Fix

Disable the use of NIS/NIS+. Use as a replacement Kerberos or LDAP.
V-899 No Change
Findings ID: GEN001440 Rule ID: SV-64577r1_rule Severity: low CCI: CCI-000225

Discussion

If users do not have a valid home directory, there is no place for the storage and control of files they own.System Administrator

Checks

Use pwck to verify home directory assignments are present.

# pwck

If any user is not assigned a home directory, this is a finding.

Fix

Assign a home directory to any user without one.
V-900 No Change
Findings ID: GEN001460 Rule ID: SV-64579r1_rule Severity: low CCI: CCI-000225

Discussion

If a user has a home directory defined that does not exist, the user may be given the / directory, by default, as the current working directory upon logon. This could create a Denial of Service because the user would not be able to perform useful tasks in this location.System Administrator

Checks

Use pwck to verify assigned home directories exist.

# pwck

If any user's assigned home directory does not exist, this is a finding.

Fix

If a user has no home directory, determine why. If possible, delete accounts without a home directory. If the account is valid, then create the home directory using the appropriate system administration utility or manually.

For instance: mkdir directoryname; copy the skeleton files into the directory; chown accountname for the new directory and the skeleton files. Document all changes.
V-901 No Change
Findings ID: GEN001480 Rule ID: SV-64585r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on home directories allow unauthorized access to user files.System Administrator

Checks

Check the home directory mode of each user in /etc/passwd.

Procedure:
# cut -d: -f6 /etc/passwd|sort|uniq|xargs -n1 ls -ld

If a user home directory's mode is more permissive than 0750, this is a finding.

Note: Application directories are allowed and may need 0755 permissions (or greater) for correct operation.

Fix

Change the mode of user home directories to 0750 or less permissive.

Procedure (example):
# chmod 0750 <home directory>

Note: Application directories are allowed and may need 0755 permissions (or greater) for correct operation.
V-902 No Change
Findings ID: GEN001500 Rule ID: SV-64589r1_rule Severity: medium CCI: CCI-000225

Discussion

If users do not own their home directories, unauthorized users could access user files.System Administrator

Checks

Check the ownership of each user home directory listed in the /etc/passwd file.

Procedure:
# cut -d : -f 6 /etc/passwd | xargs -n1 ls -ld

If any user home directory is not owned by the assigned user, this is a finding.

Fix

Change the owner of a user's home directory to its assigned user.

Procedure:
# chown <user> <home directory>
V-903 No Change
Findings ID: GEN001520 Rule ID: SV-63825r1_rule Severity: medium CCI: CCI-000225

Discussion

If the Group Identifier (GID) of the home directory is not the same as the GID of the user, this would allow unauthorized access to files.System Administrator

Checks

Check the group ownership for each user in the /etc/passwd file.

Procedure:
# cut -d : -f 6 /etc/passwd | xargs -n1 ls -ld

If any user home directory is not group-owned by the assigned user's primary group, this is a finding. Home directories for application accounts requiring different group ownership must be documented using site-defined procedures.

Fix

Change the group-owner for user home directories to the primary group of the assigned user.

Procedure:
Find the primary group of the user (GID) which is the fourth field of the user entry in /etc/passwd.

# chgrp <GID> <user home directory>

Document all changes.
V-904 No Change
Findings ID: GEN001860 Rule ID: SV-63339r2_rule Severity: medium CCI: CCI-000225

Discussion

Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.System Administrator

Checks

NOTE: The following commands must be run in the BASH shell.

Check the ownership of local initialization files.

Procedure:

# ls -al /<usershomedirectory>/.login
# ls -al /<usershomedirectory>/.cshrc
# ls -al /<usershomedirectory>/.logout
# ls -al /<usershomedirectory>/.profile
# ls -al /<usershomedirectory>/.bash_profile
# ls -al /<usershomedirectory>/.bashrc
# ls -al /<usershomedirectory>/.bash_logout
# ls -al /<usershomedirectory>/.env
# ls -al /<usershomedirectory>/.dtprofile
# ls -al /<usershomedirectory>/.dispatch
# ls -al /<usershomedirectory>/.emacs
# ls -al /<usershomedirectory>/.exrc
# find /<usershomedirectory>/.dt ! -fstype nfs ! -user <username> -exec ls -ld {} \;

If local initialization files are not owned by the home directory's user, this is a finding.

Fix

Change the ownership of the startup and login files in the user's directory to the user or root, as appropriate.

Examine each user's home directory and verify all filenames beginning with "." are owned by the owner of the directory or root.

If they are not, use the chown command to change the owner to the user and research the reasons why the owners were not assigned as required.

Procedure:

# chown username .filename

Document all changes.
V-905 No Change
Findings ID: GEN001880 Rule ID: SV-63345r1_rule Severity: medium CCI: CCI-000225

Discussion

Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.System Administrator

Checks

Check the modes of local initialization files.

Procedure:
# ls -al /<usershomedirectory>/.bashrc
# ls -al /<usershomedirectory>/.bash_login
# ls -al /<usershomedirectory>/.bash_logout
# ls -al /<usershomedirectory>/.bash_profile
# ls -al /<usershomedirectory>/.cshrc
# ls -al /<usershomedirectory>/.kshrc
# ls -al /<usershomedirectory>/.login
# ls -al /<usershomedirectory>/.logout
# ls -al /<usershomedirectory>/.profile
# ls -al /<usershomedirectory>/.tcshrc
# ls -al /<usershomedirectory>/.env
# ls -al /<usershomedirectory>/.dtprofile (permissions should be 0755)
# ls -al /<usershomedirectory>/.dispatch
# ls -al /<usershomedirectory>/.emacs
# ls -al /<usershomedirectory>/.exrc
# find /<usershomedirectory>/.dt ! -fstype nfs \( -perm -0002 -o -perm -0020 \) -exec ls -ld {} \; (permissions not to be more
permissive than 0755)

If local initialization files are more permissive than 0740 or the .dt directory is more permissive than 0755 or the .dtprofile file is more permissive than 0755, this is a finding.

Fix

Ensure user startup files have permissions of 0740 or more restrictive. Examine each user's home directory and verify all file names beginning with "." have access permissions of 0740 or more restrictive. If they do not, use the chmod command to correct the vulnerability.

Procedure:
# chmod 0740 .filename

Note: The period is part of the file name and is required.
V-906 No Change
Findings ID: GEN001580 Rule ID: SV-63843r1_rule Severity: medium CCI: CCI-000225

Discussion

If the startup files are writable by other users, they could modify the startup files to insert malicious commands into the startup files.System Administrator

Checks

Check run control script modes.
# cd /etc
# ls -lL rc*
# cd /etc/init.d
# ls -l
If any run control script has a mode more permissive than 0755, this is a finding.

Fix

Ensure all system startup files have mode 0755 or less permissive. Examine the "rc" files, and all files in the rc1.d (rc2.d, and so on) directories, and in the /etc/init.d directory to ensure they are not world-writable. If they are world-writable, use the chmod command to correct the vulnerability and research why they are world-writable.

Procedure:
# chmod 755 <startup file>
V-907 No Change
Findings ID: GEN001600 Rule ID: SV-63849r4_rule Severity: medium CCI: CCI-000366

Discussion

The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Verify run control scripts' library search paths.

# grep -r '\bPATH\b' /etc/rc* /etc/init.d

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the run control script and remove any relative path entries from the executable search path variable that are not documented with the ISSO.

Remove any empty path entries that are defined in these files.
V-910 No Change
Findings ID: GEN001640 Rule ID: SV-63855r1_rule Severity: high CCI: CCI-000225

Discussion

World-writable files could be modified accidentally or maliciously to compromise system integrity.System Administrator

Checks

Check the permissions on the files or scripts executed from system startup scripts to see if they are world-writable.
Create a list of all potential run command level scripts.
ls -l /etc/init.d/* | tr '\011' ' ' | tr -s ' ' | cut -f 9,9 -d " "

Create a list of world writeable files.
# find / -perm -002 -type f >> worldWriteableFileList

Determine if any of the world writeable files in worldWriteableFileList are called from the run command level scripts. Note: Depending upon the number of scripts vs. world writeable files, it may be easier to inspect the scripts manually.
# more `ls -l /etc/init.d/* | tr '\011' ' ' | tr -s ' ' | cut -f 9,9 -d "`

If any system startup script executes any file or script that is world-writable, this is a finding.

Fix

Remove the world-writable permission from programs or scripts executed by run control scripts.

Procedure:
# chmod o-w <program or script executed from run control script>
V-913 No Change
Findings ID: GEN002000 Rule ID: SV-63591r1_rule Severity: medium CCI: CCI-000196

Discussion

Unencrypted passwords for remote FTP servers may be stored in .netrc files. Policy requires passwords be encrypted in storage and not used in access scripts.System Administrator

Checks

Check the system for the existence of any .netrc files.

Procedure:
# find / -name .netrc

If any .netrc file exists, this is a finding.

Fix

Remove the .netrc file(s).

Procedure:
# find / -name .netrc
# rm <.netrc file>
V-914 No Change
Findings ID: GEN001540 Rule ID: SV-63831r1_rule Severity: low CCI: CCI-000225

Discussion

If users do not own the files in their directories, unauthorized users may be able to access them. Additionally, if files are not owned by the user, this could be an indication of system compromise.trueSystem AdministratorInformation Assurance Officer

Checks

For each user in the /etc/passwd file, check for the presence of files and directories within the user's home directory not owned by the home directory owner.

Procedure:
# find /<usershomedirectory> ! -fstype nfs ! -user <username> ! \( -name .bashrc -o -name .bash_login -o -name .bash_logout -o -name .bash_profile -o -name .cshrc -o -name .kshrc -o -name .login -o -name .logout -o -name .profile -o -name .tcshrc -o -name .env -o -name .dtprofile -o -name .dispatch -o -name .emacs -o -name .exrc \) -exec ls -ld {} \;

If user home directories contain files or directories not owned by the home directory owner, this is a finding.

Fix

Change the ownership of files and directories in user home directories to the owner of the home directory.

Procedure:
# chown accountowner filename
V-915 No Change
Findings ID: GEN001560 Rule ID: SV-63837r1_rule Severity: low CCI: CCI-000225

Discussion

Excessive permissions allow unauthorized access to user files.
trueSystem AdministratorInformation Assurance Officer

Checks

For each user in the /etc/passwd file, check for files and directories with a mode more permissive than 0750.

Procedure:
# find /<usershomedirectory> ! -fstype nfs ! \( -name .bashrc -o -name .bash_login -o -name .bash_logout -o -name .bash_profile -o -name .cshrc -o -name .kshrc -o -name .login -o -name .logout -o -name .profile -o -name .tcshrc -o -name .env -o -name .dtprofile -o -name .dispatch -o -name .emacs -o -name .exrc \) \( -perm -0001 -o -perm -0002 -o -perm -0004 -o -perm -0020 -o -perm -2000 -o -perm -4000 \) -exec ls -ld {} \;

If user home directories contain files or directories more permissive than 0750, this is a finding.

Fix

Change the mode of files and directories within user home directories to 0750.

Procedure:
# chmod 0750 filename

Document all changes.
V-916 No Change
Findings ID: GEN002120 Rule ID: SV-63651r1_rule Severity: medium CCI: CCI-000366

Discussion

The shells file (or equivalent) lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized unsecure shell.System Administrator

Checks

Verify /etc/shells exists.
# ls -l /etc/shells
If the file does not exist, this is a finding.

Fix

Create a /etc/shells file containing a list of valid system shells. Consult vendor documentation for an appropriate list of system shells.

Procedure:
# echo "/bin/bash" >> /etc/shells
# echo "/bin/csh" >> /etc/shells
(Repeat as necessary for other shells.)
V-917 No Change
Findings ID: GEN002140 Rule ID: SV-63671r2_rule Severity: medium CCI: CCI-000366

Discussion

The shells file lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized unsecure shell.System Administrator

Checks

Confirm the login shells referenced in the /etc/passwd file are listed in the /etc/shells file.

Procedure:

Determine which shells are permitted for use by users:
# more /etc/shells

Note: /usr/bin/false, /bin/false, /dev/null, /sbin/nologin, /bin/sync, /sbin/halt, /sbin/shutdown, (and equivalents) cannot be placed in the /etc/shells file.

Determine which shells are being used:

# more /etc/passwd (optionally shells found in /etc/passwd can be grepped for in /etc/shells)

If any shells are found that are not in /etc/shells, or if false shells are found in /etc/shells, then this is a finding.

Fix

Use the "chsh" utility or edit the /etc/passwd file and correct the error by changing the default shell of the account in error to an acceptable shell name contained in the /etc/shells file.

Example:
# chsh -s /bin/bash testuser
V-918 No Change
Findings ID: GEN000760 Rule ID: SV-64285r1_rule Severity: medium CCI: CCI-000017

Discussion

On some systems, accounts with disabled passwords still allow access using rcp, remsh, or rlogin through equivalent remote hosts. All that is required is the remote host name and the user name match an entry in a hosts.equiv file and have a .rhosts file in the user directory. Using a shell called /bin/false or /dev/null (or an equivalent) will add a layered defense.

Non-interactive accounts on the system, such as application accounts, may be documented exceptions.trueSystem Administrator

Checks

Indications of inactive accounts are those that have no entries in the "last" log. Check the date in the "last" log to verify it is within the last 35 days or the maximum numbers of days set by the site if more restrictive. If an inactive account is not disabled via an entry in the password field in the /etc/passwd or /etc/shadow (or equivalent), check the /etc/passwd file to check if the account has a valid shell.

The passwd command can also be used to list a status for an account. For example, the following may be used to provide status information on each local account:

NOTE: The following must be done in the BASH shell.

# cut -d: -f1 /etc/passwd | xargs -n1 passwd -S

If an inactive account is found not disabled, this is a finding.

Fix

All inactive accounts will have /sbin/nologin (or an equivalent), as the default shell in the /etc/passwd file and have the password disabled. Examine the user accounts using the "last" command. Note the date of last login for each account. If any (other than system and application accounts) exceed 35 days or the maximum number of days set by the site, not to exceed 35 days, then disable the accounts using system-config-users tool. Alternately place a shell field of /sbin/nologin /bin/false or /dev/null in the passwd file entry for the account.
V-921 No Change
Findings ID: GEN002200 Rule ID: SV-63677r1_rule Severity: medium CCI: CCI-000225

Discussion

If shell files are owned by users other than root or bin, they could be modified by intruders or malicious users to perform unauthorized actions.System Administrator

Checks

Check the ownership of the system shells.
# cat /etc/shells | xargs -n1 ls -l
If any shell is not owned by root or bin, this is a finding.

Fix

Change the ownership of the shell with incorrect ownership.
# chown root <shell>
V-922 No Change
Findings ID: GEN002220 Rule ID: SV-63713r1_rule Severity: high CCI: CCI-000225

Discussion

Shells with world/group write permissions give the ability to maliciously modify the shell to obtain unauthorized access.System Administrator

Checks

If /etc/shells exists, check the group ownership of each shell referenced.
# cat /etc/shells | xargs -n1 ls -l

Otherwise, check any shells found on the system.
# find / -name "*sh" | xargs -n1 ls -l

If a shell has a mode more permissive than 0755, this is a finding.

Fix

Change the mode of the shell.
# chmod 0755 <shell>
V-923 No Change
Findings ID: GEN002260 Rule ID: SV-63209r3_rule Severity: low CCI: CCI-000318

Discussion

If an unauthorized device is allowed to exist on the system, there is the possibility the system may perform unauthorized operations.System AdministratorInformation Assurance Officer

Checks

Determine if there are any device files outside of /dev:

# find / -type b -o -type c |more

Check for the presence of an aide on the system:

# rpm -qa | grep aide

If aide is not installed, ask the SA what file integrity tool is being used to check the system.

Check the global crontabs for the presence of an "aide" job to run at least weekly, if aide is installed. Otherwise, check for the presence of a cron job to run the alternate file integrity checking application.

# grep aide /etc/cron*/*

If a tool is being run, then the configuration file for the appropriate tool needs to be checked for selection lines for /dev and any other directories/subdirectories that contain device files.

Review the process to determine if the system is checked for extraneous device files on a weekly basis.

If no weekly automated or manual process is in place, this is a finding.

If the process is not identifying extraneous device files, this is a finding.

Fix

Establish a weekly automated or manual process to create a list of device files on the system and determine if any files have been added, moved, or deleted since the last list was generated.

A list of device files can be generated with this command:

# find / -type b -o -type c > device-file-list
V-924 No Change
Findings ID: GEN002280 Rule ID: SV-63229r3_rule Severity: medium CCI: CCI-000225

Discussion

System device files in writable directories could be modified, removed, or used by an unprivileged user to control system hardware.System Administrator

Checks

Find all world-writable device files existing anywhere on the system.

Procedure:
# find / -perm -2 -a \( -type b -o -type c \) > devicelist

Check the permissions on the directories above subdirectories containing device files.

If any of the device files or their parent directories are world-writable, excepting device files specifically intended to be world-writable such as /dev/null, this is a finding.

These world-writable files on installation are intended to be world-writable:

/dev/full
/dev/null
/selinux/null
/dev/ptmx
/dev/random
/dev/tty
/dev/vsock
/dev/zero
/dev/log

Fix

Remove the world-writable permission from the device file(s).

Procedure:

# chmod o-w <device file>

Document all changes.
V-925 No Change
Findings ID: GEN002300 Rule ID: SV-63241r1_rule Severity: medium CCI: CCI-000225

Discussion

System backups could be accidentally or maliciously overwritten and destroy the ability to recover the system if a compromise should occur. Unauthorized users could also copy system files.trueSystem AdministratorInformation Assurance Officer

Checks

Check the system for world-writable device files.

Procedure:
# find / -perm -2 -a \( -type b -o -type c \) -exec ls -ld {} \;

Ask the SA to identify any device files used for backup purposes.

If any device file(s) used for backup are writable by users other than root or the designated backup user, this is a finding.

Fix

Use the chmod command to remove the world-writable bit from the backup device files.

Procedure:
# chmod o-w <back device filename>

Document all changes.
V-928 No Change
Findings ID: GEN005740 Rule ID: SV-64237r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of the NFS export configuration file to root provides the designated owner and possible unauthorized users with the potential to change system configuration which could weaken the system's security posture.System Administrator

Checks

Check the owner of the exports file.

Example:
# ls -lL /etc/exports

If the export configuration file is not owned by root, this is a finding.

Fix

Change the owner of the exports file to root.

Example:
# chown root /etc/exports
V-929 No Change
Findings ID: GEN005760 Rule ID: SV-64199r1_rule Severity: low CCI: CCI-000225

Discussion

Excessive permissions on the NFS export configuration file could allow unauthorized modification of the file, which could result in Denial of Service to authorized NFS exports and the creation of additional unauthorized exports.System Administrator

Checks

# ls -lL /etc/exports
If the file has a mode more permissive than 0644, this is a finding.

Fix

# chmod 0644 /etc/exports
V-931 No Change
Findings ID: GEN005800 Rule ID: SV-64189r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of sensitive files or directories to root provides the designated owner and possible unauthorized users with the potential to access sensitive information or change system configuration which could weaken the system's security posture.System Administrator

Checks

Check for NFS exported file systems.

Procedure:
# cat /etc/exports
For each file system displayed, check the ownership.

# ls -lLa <exported file system path>

If the files and directories are not owned by root, this is a finding.

Fix

Change the ownership of exported file systems not owned by root.

Procedure:
# chown root <path>
V-932 No Change
Findings ID: GEN005820 Rule ID: SV-64169r1_rule Severity: medium CCI: CCI-000062

Discussion

When an NFS server is configured to deny remote root access, a selected UID and GID are used to handle requests from the remote root user. The UID and GID should be chosen from the system to provide the appropriate level of non-privileged access.System Administrator

Checks

Check if the 'anonuid' and 'anongid' options are set correctly for exported file systems.

List exported filesystems:
# exportfs -v

Each of the exported file systems should include an entry for the 'anonuid=' and 'anongid=' options set to "-1" or an equivalent (60001, 65534, or 65535).

If appropriate values for 'anonuid' or 'anongid' are not set, this is a finding.

Fix

Edit "/etc/exports" and set the "anonuid=-1" and "anongid=-1" options for exports lacking it.

Re-export the filesystems.
V-933 No Change
Findings ID: GEN005840 Rule ID: SV-64163r1_rule Severity: medium CCI: CCI-000366

Discussion

The NFS access option limits user access to the specified level. This assists in protecting exported file systems. If access is not restricted, unauthorized hosts may be able to access the system's NFS exports.System Administrator

Checks

Check the permissions on exported NFS file systems.

Procedure:
# exportfs -v

If the exported file systems do not contain the 'rw' or 'ro' options specifying a list of hosts or networks, this is a finding.

Fix

Edit /etc/exports and add ro and/or rw options (as appropriate) specifying a list of hosts or networks which are permitted access. Re-export the file systems.
V-935 No Change
Findings ID: GEN005880 Rule ID: SV-64157r1_rule Severity: medium CCI: CCI-000225

Discussion

If the NFS server allows root access to local file systems from remote hosts, this access could be used to compromise the system.System AdministratorInformation Assurance OfficerInformation Assurance Manager

Checks

List the exports.
# cat /etc/exports
If any export contains "no_root_squash" or does not contain "root_squash" or "all_squash", this is a finding.

Fix

Edit the "/etc/exports" file and add "root_squash" (or "all_squash") and remove "no_root_squash".
V-936 No Change
Findings ID: GEN005900 Rule ID: SV-64147r1_rule Severity: medium CCI: CCI-000225

Discussion

Enabling the nosuid mount option prevents the system from granting owner or group-owner privileges to programs with the suid or sgid bit set. If the system does not restrict this access, users with unprivileged access to the local system may be able to acquire privileged access by executing suid or sgid files located on the mounted NFS file system.System AdministratorInformation Assurance OfficerInformation Assurance Manager

Checks

Check the system for NFS mounts not using the "nosuid" option.

Procedure:
# mount -v | grep " type nfs " | egrep -v "nosuid"

If the mounted file systems do not have the "nosuid" option, this is a finding.

Fix

Edit "/etc/fstab" and add the "nosuid" option for all NFS file systems. Remount the NFS file systems to make the change take effect.
V-940 No Change
Findings ID: GEN006580 Rule ID: SV-63577r1_rule Severity: medium CCI: CCI-000366

Discussion

Access control programs (such as TCP_WRAPPERS) provide the ability to enhance system security posture.System Administrator

Checks

The tcp_wrappers package is provided with the operating system. Other access control programs may be available but will need to be checked manually.

Determine if tcp_wrappers is installed.
# rpm -qa | grep tcp_wrappers
If no package is listed, this is a finding.

Fix

Install and configure the tcp_wrappers package.
V-941 No Change
Findings ID: GEN006600 Rule ID: SV-63571r2_rule Severity: medium CCI: CCI-000126

Discussion

If access attempts are not logged, then multiple attempts to log on to the system by an unauthorized user may go undetected.System Administrator

Checks

The tcp_wrappers package is provided with the RHEL distribution. Other access control programs may be available but will need to be checked manually. Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Normally, tcpd logs to the mail facility in "/etc/syslog.conf" or “/etc/rsyslog.conf”. Determine if syslog or rsyslog is configured to log events by tcpd.

Procedure:

# more /etc/syslog.conf

Or:

# more /etc/rsyslog.conf

Look for entries similar to the following:

mail.debug /var/adm/maillog
mail.none /var/adm/maillog
mail.* /var/log/mail
authpriv.info /var/log/messages

The above entries would indicate mail alerts are being logged.

If no entries for mail exist, then tcpd is not logging this is a finding.

If an alternate access control program is used and it does not provide logging of access attempts, this is a finding.

Fix

Configure the access restriction program to log every access attempt. Ensure the implementation instructions for tcp_wrappers are followed so system access attempts are recorded to the system log files. If an alternate application is used, it must support this function.
V-974 No Change
Findings ID: GEN002960 Rule ID: SV-64415r2_rule Severity: medium CCI: CCI-000225

Discussion

The cron facility allows users to execute recurring jobs on a regular and unattended basis. The cron.allow file designates accounts allowed to enter and execute jobs using the cron facility. If the cron.allow file is not present, users listed in the cron.deny file are not allowed to use the cron facility. Improper configuration of cron may open the facility up for abuse by system intruders and malicious users.System Administrator

Checks

This check is not applicable if only the root user is permitted to use cron.

Check for the existence of the cron.allow and cron.deny files.

# ls -lL /etc/cron.allow
# ls -lL /etc/cron.deny

If neither file exists, this is a finding.

Fix

Create /etc/cron.allow and/or /etc/cron.deny with appropriate content and reboot the system to ensure no lingering cron jobs are processed.
V-975 No Change
Findings ID: GEN002980 Rule ID: SV-64411r1_rule Severity: medium CCI: CCI-000225

Discussion

A readable and/or writable cron.allow file by users other than root could allow potential intruders and malicious users to use the file contents to help discern information, such as who is allowed to execute cron programs, which could be harmful to overall system and network security.System Administrator

Checks

Check mode of the cron.allow file.

Procedure:
# ls -lL /etc/cron.allow

If the file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the cron.allow file to 0600.

Procedure:
# chmod 0600 /etc/cron.allow
V-976 No Change
Findings ID: GEN003000 Rule ID: SV-64405r1_rule Severity: medium CCI: CCI-000225

Discussion

If cron executes group-writable or world-writable programs, there is a possibility that unauthorized users could manipulate the programs with malicious intent. This could compromise system and network security.System Administrator

Checks

List all cronjobs on the system.
Procedure:

# ls /var/spool/cron

# ls /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls /etc/cron*|grep -v deny

If cron jobs exist under any of the above directories, use the following command to search for programs executed by cron:

# more <cron job file>

Perform a long listing of each program file found in the cron file to determine if the file is group-writable or world-writable.

# ls -la <cron program file>

If cron executes group-writable or world-writable files, this is a finding.

Fix

Remove the world-writable and group-writable permissions from the cron program file(s) identified.

# chmod go-w <cron program file>
V-977 No Change
Findings ID: GEN003020 Rule ID: SV-64403r1_rule Severity: medium CCI: CCI-000225

Discussion

If cron programs are located in or subordinate to world-writable directories, they become vulnerable to removal and replacement by malicious users or system intruders.System Administrator

Checks

List all cronjobs on the system.
Procedure:

# ls /var/spool/cron

# ls /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls /etc/cron*|grep -v deny

If cron jobs exist under any of the above directories, use the following command to search for programs executed by at:

# more <cron job file>

Perform a long listing of each directory containing program files found in the cron file to determine if the directory is world-writable.

# ls -ld <cron program directory>

If cron executes programs in world-writable directories, this is a finding.

Fix

Remove the world-writable permission from the cron program directories identified.

Procedure:
# chmod o-w <cron program directory>
V-978 No Change
Findings ID: GEN003080 Rule ID: SV-64391r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.System Administrator

Checks

Check the mode of the crontab files.
# ls -lL /var/spool/cron/
# ls -lL /etc/cron.d/
# ls -lL /etc/crontab

If any crontab file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the crontab files.

# chmod 0600 /var/spool/cron/* /etc/cron.d/* /etc/crontab
V-979 No Change
Findings ID: GEN003100 Rule ID: SV-64375r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured.System Administrator

Checks

Check the mode of the crontab directories.

Procedure:
# ls -ld /var/spool/cron

# ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -ld /etc/cron*|grep -v deny

If the mode of any of the crontab directories is more permissive than 0755, this is a finding.

Fix

Change the mode of the crontab directories.

# chmod 0755 <crontab directory>
V-980 No Change
Findings ID: GEN003120 Rule ID: SV-64293r1_rule Severity: medium CCI: CCI-000225

Discussion

Incorrect ownership of the cron or crontab directories could permit unauthorized users the ability to alter cron jobs and run automated jobs as privileged users. Failure to give ownership of cron or crontab directories to root or to bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Check the owner of the crontab directories.
Procedure:

# ls -ld /var/spool/cron

# ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -ld /etc/cron*|grep -v deny


If the owner of any of the crontab directories is not root or bin, this is a finding.

Fix

Change the mode of the crontab directories.

# chown root <crontab directory>
V-981 No Change
Findings ID: GEN003140 Rule ID: SV-64305r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. Failure to give group-ownership of cron or crontab directories to a system group provides the designated group and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Check the group owner of cron and crontab directories.

Procedure:
# ls -ld /var/spool/cron

# ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -ld /etc/cron*|grep -v deny


If a directory is not group-owned by root, sys, bin, or cron, this is a finding.

Fix

Change the group owner of cron and crontab directories.

# chgrp root <crontab directory>
V-982 No Change
Findings ID: GEN003160 Rule ID: SV-64313r2_rule Severity: medium CCI: CCI-000126

Discussion

Cron logging can be used to trace the successful or unsuccessful execution of cron jobs. It can also be used to spot intrusions into the use of the cron facility by unauthorized and malicious users.
System Administrator

Checks

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

# grep cron /etc/syslog.conf

Or:

# grep cron /etc/rsyslog.conf

If cron logging is not configured, this is a finding.

Check the configured cron log file found in the cron entry of /etc/syslog.conf or /etc/rsyslog.conf (normally /var/log/cron).

# ls -lL /var/log/cron

If this file does not exist, or is older than the last cron job, this is a finding.

Fix

Edit /etc/syslog.conf or /etc/rsyslog.conf and setup cron logging.
V-983 No Change
Findings ID: GEN003180 Rule ID: SV-64317r2_rule Severity: medium CCI: CCI-000225

Discussion

Cron logs contain reports of scheduled system activities and must be protected from unauthorized access or manipulation.
System Administrator

Checks

Check the mode of the cron log file.

Procedure:

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Check the configured cron log file found in the cron entry in /etc/syslog.conf or /etc/rsyslog.conf (normally /var/log/cron).

# grep cron /etc/syslog.conf

Or:

# grep cron /etc/rsyslog.conf

# ls -lL /var/log/cron

If the mode is more permissive than 0600, this is a finding.

Fix

Change the mode of the cron log file.

# chmod 0600 /var/log/cron
V-984 No Change
Findings ID: GEN003280 Rule ID: SV-64369r1_rule Severity: medium CCI: CCI-000225

Discussion

The "at" facility selectively allows users to execute jobs at deferred times. It is usually used for one-time jobs. The at.allow file selectively allows access to the "at" facility. If there is no at.allow file, there is no ready documentation of who is allowed to submit "at" jobs.System Administrator

Checks

If the "at" package is not installed, this is not applicable.

Check for the existence of at.allow and at.deny files.
# ls -lL /etc/at.allow
# ls -lL /etc/at.deny
If neither file exists, this is a finding.

Fix

Create at.allow and/or at.deny files containing appropriate lists of users to be allowed or denied access to the "at" daemon.
V-985 No Change
Findings ID: GEN003300 Rule ID: SV-64371r1_rule Severity: medium CCI: CCI-000225

Discussion

On some systems, if there is no at.allow file and there is an empty at.deny file, then the system assumes everyone has permission to use the "at" facility. This could create an insecure setting in the case of malicious users or system intruders.trueSystem AdministratorInformation Assurance Officer

Checks

# more /etc/at.deny
If the at.deny file exists and is empty, this is a finding.

Fix

Add appropriate users to the at.deny file, or remove the empty at.deny file if an at.allow file exists.
V-986 No Change
Findings ID: GEN003320 Rule ID: SV-64379r1_rule Severity: medium CCI: CCI-000225

Discussion

Default accounts, such as bin, sys, adm, uucp, daemon, and others, should never have access to the "at" facility. This would create a possible vulnerability open to intruders or malicious users.System Administrator

Checks

# more /etc/at.allow
If default accounts (such as bin, sys, adm, and others) are listed in the at.allow file, this is a finding.

Fix

Remove the default accounts (such as bin, sys, adm, and others, traditionally UID less than 500) from the at.allow file.
V-987 No Change
Findings ID: GEN003340 Rule ID: SV-64453r1_rule Severity: medium CCI: CCI-000225

Discussion

Permissions more permissive than 0600 (read, write and execute for the owner) may allow unauthorized or malicious access to the at.allow and/or at.deny files.System Administrator

Checks

Check the mode of the at.allow file.
# ls -lL /etc/at.allow
If the at.allow file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the at.allow file.
# chmod 0600 /etc/at.allow
V-988 No Change
Findings ID: GEN003360 Rule ID: SV-64469r1_rule Severity: medium CCI: CCI-000225

Discussion

If the "at" facility executes world-writable or group-writable programs, it is possible for the programs to be accidentally or maliciously changed or replaced without the owner's intent or knowledge. This would cause a system security breach.System Administrator

Checks

List the "at" jobs on the system.

Procedure:
# ls -la /var/spool/at

For each "at" job file, determine which programs are executed.

Procedure:
# more <at job file>

Check the each program executed by "at" for group- or world-writable permissions.
Procedure:
# ls -la <at program file>

If "at" executes group or world-writable programs, this is a finding.

Fix

Remove group-write and world-write permissions from files executed by at jobs.

Procedure:
# chmod go-w <file>
V-989 No Change
Findings ID: GEN003380 Rule ID: SV-64475r1_rule Severity: medium CCI: CCI-000225

Discussion

If "at" programs are located in, or subordinate, to world-writable directories, they become vulnerable to removal and replacement by malicious users or system intruders.System Administrator

Checks

List any "at" jobs on the system.
Procedure:
# ls /var/spool/at

For each "at" job, determine which programs are executed by "at."
Procedure:
# more <at job file>

Check the directory containing each program executed by "at" for world-writable permissions.
Procedure:
# ls -la <at program file directory>

If "at" executes programs in world-writable directories, this is a finding.

Fix

Remove the world-writable permission from directories containing programs executed by "at".

Procedure:
# chmod o-w <at program directory>
V-993 No Change
Findings ID: GEN005300 Rule ID: SV-63371r1_rule Severity: high CCI: CCI-000178

Discussion

Whether active or not, default SNMP passwords, users, and passphrases must be changed to maintain security. If the service is running with the default authenticators, then anyone can gather data about the system and the network and use the information to potentially compromise the integrity of the system or network(s).System Administrator

Checks

Check the SNMP configuration for default passwords.

Procedure:
Examine the default install location /etc/snmp/snmpd.conf
or:
# find / -name snmpd.conf
# more <snmpd.conf file>

Identify any community names or user password configuration. If any community name or password is set to a default value such as "public", "private", "snmp-trap", or "password", or any value which does not meet DISA password requirements, this is a finding.

Fix

Change the default passwords.
To change them, locate the file snmpd.conf.

Edit the file.

Locate the line system-group-read-community which has a default password of "public" and make the password something more secure and less guessable.

Do the same for the lines reading system-group-write-community, read-community, write-community, trap and trap-community.

Read the information in the file carefully. The trap is defining who to send traps to, for instance, by default. It is not a password, but the name of a host.
V-994 No Change
Findings ID: GEN005320 Rule ID: SV-63425r1_rule Severity: medium CCI: CCI-000225

Discussion

The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification.System Administrator

Checks

Check the mode of the SNMP daemon configuration file.

Procedure:
Examine the default install location /etc/snmp/snmpd.conf
or:
# find / -name snmpd.conf

# ls -lL <snmpd.conf file>

If the snmpd.conf file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the SNMP daemon configuration file to 0600.

Procedure:
# chmod 0600 <snmpd.conf>
V-995 No Change
Findings ID: GEN005340 Rule ID: SV-63429r1_rule Severity: medium CCI: CCI-000225

Discussion

The ability to read the MIB file could impart special knowledge to an intruder or malicious user about the ability to extract compromising information about the system or network.System Administrator

Checks

Check the modes for all Management Information Base (MIB) files on the system.

Procedure:
# find / -name *.mib
# ls -lL <mib file>

Any file returned with a mode 0640 or less permissive is a finding.

Fix

Change the mode of MIB files to 0640.

Procedure:
# chmod 0640 <mib file>
V-1010 No Change
Findings ID: GEN002480 Rule ID: SV-63673r1_rule Severity: medium CCI: CCI-000366

Discussion

World-writable files and directories make it easy for a malicious user to place potentially compromising files on the system.

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, (e.g., /tmp), and for directories requiring global read/write access.System Administrator

Checks

Check the system for world-writable files.

Procedure:
# find / -perm -2 -a \( -type d -o -type f \) -exec ls -ld {} \;

If any world-writable files are located, except those required for system operation such as /tmp and /dev/null, this is a finding.

Fix

Remove or change the mode for any world-writable file on the system not required to be world-writable.

Procedure:
# chmod o-w <file>

Document all changes
V-1011 No Change
Findings ID: GEN003800 Rule ID: SV-63989r1_rule Severity: low CCI: CCI-000134

Discussion

Inetd or xinetd logging and tracing allows the system administrators to observe the IP addresses connecting to their machines and what network services are being sought. This provides valuable information when trying to find the source of malicious users and potential malicious users.System Administrator

Checks

The /etc/xinetd.conf file and each file in the /etc/xinetd.d directory file should be examined for the following:

Procedure:
log_type = SYSLOG authpriv
log_on_success = HOST PID USERID EXIT
log_on_failure = HOST USERID

If xinetd is running and logging is not enabled, this is a finding.

Fix

Edit each file in the /etc/xinetd.d directory and the /etc/xinetd.conf file to contain:
log_type = SYSLOG authpriv
log_on_success = HOST PID USERID EXIT
log_on_failure = HOST USERID

The /etc/xinetd.conf file contains default values that will hold true for all services unless individually modified in the service's xinetd.d file.

To make the new settings effective, restart the xinetd service:
# service xinetd restart
V-1013 No Change
Findings ID: GEN008600 Rule ID: SV-63139r1_rule Severity: high CCI: CCI-000366

Discussion

The ability to boot from removable media is the same as being able to boot into single user, or maintenance, mode without a password. This ability could allow a malicious user to boot the system and perform changes with the potential to compromise or damage the system. It could also allow the system to be used for malicious purposes by a malicious anonymous user.System Administrator

Checks

Determine if the system is configured to boot from devices other than the system startup media. If so, this is a finding.

Fix

Configure the system to only boot from system startup media.

Procedure:
On systems with a BIOS or system controller use the BIOS interface at startup to remove all but the proper boot device from the boot device list.
V-1021 No Change
Findings ID: GEN000000-LNX00360 Rule ID: SV-62805r1_rule Severity: medium CCI: CCI-000366

Discussion

Without the correct options enabled, the Xwindows system would be less secure and there would be no screen timeout.System Administrator

Checks

Verify the options of the running Xwindows server are correct.

Procedure:
Get the running xserver information

# ps -ef |grep X

If the response contains /usr/bin/Xorg:0

/usr/bin/Xorg:0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7

this is indicative of Xorg starting through gdm. This is the default on this version of the operating system.

Examine the Xorg line:

If the "-auth" option is missing this would be a finding.
If the "-audit" option is missing or not set to 4, this is a finding.
If the "-s" option is missing or greater than 15, this is a finding.


If the response to the grep contains X:0

/usr/bin/X:0

this indicates the X server was started with the xinit command with no associated .xserverrc in the home directory of the user. No options are selected by default. This is a finding.

Otherwise if there are options on the X:0 line:
If the "-auth" option is missing this is a finding
If the "-audit" option is missing or not set to 4, this is a finding.
If the "-s" option is missing or greater than 15, this is a finding.

Fix

Enable the following options: -audit (at level 4), -auth and -s with 15 minutes as the timeout value.

Procedure for gdm:
Edit /etc/gdm/custom.conf and add the following:
[server-Standard]
name=Standard server
command=/usr/bin/Xorg -br -audit 4 -s 15
chooser=false
handled=true
flexible=true
priority=0

Procedure for xinit:
Edit or create a .xserverrc file in the user's home directory containing the startup script for xinit.
This script must have an exec line with at least these options:

exec /usr/bin/X -audit 4 -s 15 -auth <Xauth file> &

The <Xauth file> is created using the "xauth" command and is customarily located in the user's home directory with the name ".Xauthority".
V-1022 No Change
Findings ID: GEN000000-LNX00380 Rule ID: SV-62815r1_rule Severity: medium CCI: CCI-000366

Discussion

These options will detract from the security of the Xwindows system.System Administrator

Checks

If the "xorg-x11-server-Xorg" package is not installed, this is not applicable.

Verify the options of the running Xwindows server are correct.

Procedure:

Get the running xserver information

# ps -ef |grep X

If the response contains /usr/bin/Xorg:0

/usr/bin/Xorg:0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7

this is indicative of Xorg starting through gdm. This is the default window manager on this version of the operating system.

If the "-ac" option is found, this is a finding.
If the "-core" option is found, this is a finding.
If the "-nolock" option is found, this is a finding.


If the response to the grep contains X:0

/usr/bin/X:0

Examine the X:0 line:

If the "-ac" option is found, this is a finding.
If the "-core" option is found, this is a finding.
If the "-nolock" option is found, this is a finding.

Fix

Disable the unwanted options:
Procedure:
For gdm:
Remove the -ac, -core and -nolock options by creating a "command" entry in the /etc/gdm/custom.conf file with the options removed.

For Xwindows started by xinit:
Create or modify the .xserverrc script in the user's home directory to remove the -ac, -core and -nolock options from the exec /usr/bin/X command.
V-1023 No Change
Findings ID: GEN006240 Rule ID: SV-63965r1_rule Severity: medium CCI: CCI-000381

Discussion

INN servers access Usenet newsfeeds and store newsgroup articles. INN servers use the Network News Transfer Protocol (NNTP) to transfer information from the Usenet to the server and from the server to authorized remote hosts.

If this function is necessary to support a valid mission requirement, its use must be authorized and approved in the system accreditation package.System AdministratorInformation Assurance Officer

Checks

# ps -ef | egrep "innd|nntpd"

If an Internet Network News server is running, this is a finding.

Fix

Disable the INN server.
V-1025 No Change
Findings ID: GEN000000-LNX00400 Rule ID: SV-62875r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/security/access.conf file contains entries restricting access from the system console by authorized System Administrators. If the file is owned by a user other than root, it could compromise the system.System Administrator

Checks

Check access configuration ownership:

# ls -lL /etc/security/access.conf

If this file exists and is not owned by root, this is a finding.

Fix

Follow the correct configuration parameters for access configuration file. Use the chown command to configure it properly.
(for example:
# chown root /etc/security/access.conf
).
V-1026 No Change
Findings ID: GEN006080 Rule ID: SV-64123r1_rule Severity: medium CCI: CCI-001436

Discussion

SWAT is a tool used to configure Samba. It modifies Samba configuration, which can impact system security, and must be protected from unauthorized access. SWAT authentication may involve the root password, which must be protected by encryption when traversing the network.

Restricting access to the local host allows for the use of SSH TCP forwarding, if configured, or administration by a web browser on the local system.System Administrator

Checks

SWAT is a tool for configuring Samba and should only be found on a system with a requirement for Samba. If SWAT is used, it must be utilized with SSL to ensure a secure connection between the client and the server.

Procedure:

# grep -H "bin/swat" /etc/xinetd.d/*|cut -d: -f1 |xargs grep "only_from"

If the value of the "only_from" line in the "xinetd.d" file which starts "/usr/sbin/swat" is not "localhost" or the equivalent, this is a finding.

Fix

Disable SWAT or require SWAT is only accessed via SSH.

Procedure:
If SWAT is not needed for operation of the system remove the SWAT package:
# rpm -qa|grep swat

Remove "samba-swat" or "samba3x-swat" depending on which one is installed
# rpm --erase samba-swat
or
# rpm --erase samba3x-swat

If SWAT is required but not at all times disable it when it is not needed.
Modify the /etc/xinetd.d file for "swat" to contain a "disable = yes" line.

To access using SSH:
Follow vendor configuration documentation to create an stunnel for SWAT.
V-1027 No Change
Findings ID: GEN006100 Rule ID: SV-64095r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/smb.conf file allows access to other machines on the network and grants permissions to certain users. If it is owned by another user, the file may be maliciously modified and the Samba configuration could be compromised.System Administrator

Checks

Check the ownership of the /etc/samba/smb.conf file.

Procedure:
# ls -l /etc/samba/smb.conf
If an smb.conf file is not owned by root, this is a finding.

Fix

Change the ownership of the smb.conf file.

Procedure:
# chown root smb.conf
V-1028 No Change
Findings ID: GEN006140 Rule ID: SV-64087r1_rule Severity: medium CCI: CCI-000225

Discussion

If the "smb.conf" file has excessive permissions, the file may be maliciously modified and the Samba configuration could be compromised.System Administrator

Checks

Check the mode of the smb.conf file.

Procedure:
# ls -lL /etc/samba/smb.conf

If the "smb.conf" has a mode more permissive than 0644, this is a finding.

Fix

Change the mode of the smb.conf file to 0644 or less permissive.

Procedure:
# chmod 0644 smb.conf.
V-1029 No Change
Findings ID: GEN006160 Rule ID: SV-64077r1_rule Severity: medium CCI: CCI-000225

Discussion

If the "smbpasswd" file is not owned by root, it may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.System Administrator

Checks

Check the ownership of the "smbpasswd" file.

# ls -l /etc/samba/passdb.tdb /etc/samba/secrets.tdb

If the "smbpasswd" file is not owned by root, this is a finding.

Fix

Use the chown command to configure the files maintained by smbpasswd.
For instance:
# chown root /etc/samba/passdb.tdb /etc/samba/secrets.tdb
V-1030 No Change
Findings ID: GEN006220 Rule ID: SV-64055r1_rule Severity: medium CCI: CCI-000225

Discussion

Samba increases the attack surface of the system and must be restricted to communicate only with systems requiring access.System Administrator

Checks

Examine the "smb.conf" file.

# more /etc/samba/smb.conf

If the "hosts" option is not present to restrict access to a list of authorized hosts and networks, this is a finding.

Fix

Edit the "/etc/samba/smb.conf" file and set the "hosts" option to permit only authorized hosts to access Samba.
V-1032 No Change
Findings ID: GEN000540 Rule ID: SV-63659r1_rule Severity: medium CCI: CCI-000198

Discussion

The ability to change passwords frequently facilitates users reusing the same password. This can result in users effectively never changing their passwords. This would be accomplished by users changing their passwords when required and then immediately changing it to the original value.
System Administrator

Checks

Check the minimum time period between password changes for each user account is 1 day.
# cat /etc/shadow | cut -d ':' -f 4 | grep -v 1
If any results are returned, this is a finding.

Fix

Change the minimum time period between password changes for each user account to 1 day.

# passwd -n 1 <user name>
V-1046 No Change
Findings ID: GEN001100 Rule ID: SV-64449r2_rule Severity: high CCI: CCI-000197

Discussion

If a user accesses the root account (or any account) using an unencrypted connection, the password is passed over the network in clear text form and is subject to interception and misuse. This is true even if recommended procedures are followed by logging on to a named account and using the su command to access root.System Administrator

Checks

Determine if root has logged in over an unencrypted network connection.

Examine /etc/syslog.conf to confirm the location to which "authpriv" messages are being sent.

# grep authpriv.* /etc/syslog.conf

Once the file is determined, perform the following command:

# grep password <file> | more

Look for any lines that do not have sshd as the associated service.

If root has logged in over the network and sshd is not running, this is a finding.

Fix

Enable SSH on the system and use it for all remote connections used to attain root access
V-1047 No Change
Findings ID: GEN001120 Rule ID: SV-64455r1_rule Severity: medium CCI: CCI-000770

Discussion

Even though communications are encrypted, an additional layer of security may be gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account preserves the audit trail.System Administrator

Checks

Determine if the SSH daemon is configured to permit root logins.

Procedure:
# grep -v "^#" /etc/ssh/sshd_config | grep -i permitrootlogin

If the PermitRootLogin entry is not found or is not set to "no", this is a finding.

Fix

Edit the sshd_config file and set the PermitRootLogin option to "no".
V-1048 No Change
Findings ID: GEN002320 Rule ID: SV-63247r1_rule Severity: medium CCI: CCI-000225

Discussion

Audio and video devices that are globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone into a bugging device.System Administrator

Checks

Check the mode of audio devices.
# ls -lL /dev/audio* /dev/snd/*
If the mode of audio devices are more permissive than 660, this is a finding.

Fix

Change the mode of audio devices.
# chmod 0660 <audio device>
V-1049 No Change
Findings ID: GEN002340 Rule ID: SV-63301r1_rule Severity: medium CCI: CCI-000225

Discussion

Audio and video devices globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone into a bugging device.System Administrator

Checks

Check the owner of audio devices.
# ls -lL /dev/audio* /dev/snd/*
If the owner of any audio device file is not root, this is a finding.

Fix

Edit the /etc/security/console.perms.d/50-default.perms file and comment the following line:

<console> 0600 <sound> 0660 root.audio
V-1054 No Change
Findings ID: GEN000000-LNX00420 Rule ID: SV-62901r1_rule Severity: medium CCI: CCI-000225

Discussion

Depending on the access restrictions of the /etc/security/access.conf file, if the group owner were not a privileged group, it could endanger system security.System Administrator

Checks

Check access configuration group ownership:

# ls -lL /etc/security/access.conf

If this file exists and has a group-owner that is not a privileged user, this is a finding.

Fix

Use the chgrp command to ensure the group owner is root, sys, or bin.
(for example:
# chgrp root /etc/security/access.conf

).
V-1055 No Change
Findings ID: GEN000000-LNX00440 Rule ID: SV-62903r1_rule Severity: medium CCI: CCI-000225

Discussion

If the access permissions are more permissive than 0640, system security could be compromised.System Administrator

Checks

Check access configuration mode:

# ls -lL /etc/security/access.conf

If this file exists and has a mode more permissive than 0640, this is a finding.

Fix

Use the chmod command to set the permissions to 0640.
(for example:
# chmod 0640 /etc/security/access.conf

).
V-1056 No Change
Findings ID: GEN006120 Rule ID: SV-64093r1_rule Severity: medium CCI: CCI-000225

Discussion

If the group owner of the "smb.conf" file is not root or a system group, the file may be maliciously modified and the Samba configuration could be compromised.System Administrator

Checks

Check the group ownership of the "smb.conf" file.

Procedure:
# ls -lL /etc/samba/smb.conf

If the "smb.conf" file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group owner of the smb.conf file.

Procedure:
# chgrp root smb.conf
V-1058 No Change
Findings ID: GEN006180 Rule ID: SV-64069r1_rule Severity: medium CCI: CCI-000225

Discussion

If the smbpasswd file is not group-owned by root, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.System Administrator

Checks

Check "smbpasswd" ownership:

# ls -lL /etc/samba/passdb.tdb /etc/samba/secrets.tdb

If the "smbpasswd" file is not group-owned by root, this is a finding.

Fix

Use the chgrp command to ensure that the group owner of the smbpasswd file is root.

For instance:
# chgrp root /etc/samba/passdb.tdb /etc/samba/secrets.tdb
V-1059 No Change
Findings ID: GEN006200 Rule ID: SV-64063r1_rule Severity: medium CCI: CCI-000225

Discussion

If the smbpasswd file has a mode more permissive than 0600, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.System Administrator

Checks

Check the mode of files maintained using "smbpasswd".

Procedure:
# ls -lL /etc/samba/passdb.tdb /etc/samba/secrets.tdb

If a "smbpasswd" maintained file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the files maintained through smbpasswd to 0600.

Procedure:
# chmod 0600 /etc/samba/passdb.tdb /etc/samba/secrets.tdb
V-1061 No Change
Findings ID: GEN002360 Rule ID: SV-63341r2_rule Severity: medium CCI: CCI-000225

Discussion

Without privileged group owners, audio devices will be vulnerable to being used as eaves-dropping devices by malicious users or intruders to possibly listen to conversations containing sensitive information.System Administrator

Checks

Check the group-owner of audio devices.

Procedure:
# ls -lL /dev/audio* /dev/snd/*

If the group-owner of an audio device is not root, sys, bin, system, or audio this is a finding.

Fix

Change the group-owner of the audio device.

Procedure:
# chgrp <root, sys, bin, system, audio> <audio device>
V-1062 No Change
Findings ID: GEN001080 Rule ID: SV-64441r1_rule Severity: low CCI: CCI-000366

Discussion

To ensure the root shell is available in repair and administrative modes, the root shell must be located in the / file system.System Administrator

Checks

Determine if root's shell executable resides on a dedicated file system.

Procedure:
Find the location of the root user's shell

# grep "^root" /etc/passwd|cut -d: -f7|cut -d/ -f2

The result is the top level directory under / where the shell resides (e.g., usr)
Check if it is on a dedicated file system.

# grep /<top level directory> /etc/fstab

If /<top level directory> is on a dedicated file system, this is a finding.

Fix

Change the root account's shell to one present on the / file system.

Procedure:
Edit /etc/passwd and change the shell for the root account to one present on the / file system (such as /bin/sh, assuming /bin is not on a separate file system). If the system does not store shell configuration in the /etc/passwd file, consult vendor documentation for the correct procedure for the system.
V-4083 No Change
Findings ID: GEN000500 Rule ID: SV-63405r1_rule Severity: medium CCI: CCI-000057

Discussion

If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients.System Administrator

Checks

If the "xorg-x11-server-Xorg" package is not installed, this is not applicable.

For the Gnome screen saver, check the idle_activation_enabled flag.

Procedure:
# gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/idle_activation_enabled
If this does not return "true" and a documented exception has not been made by the IAO, this is a finding.

Fix

For the Gnome screen saver, set the idle_activation_enabled flag.
Procedure:
# gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type bool --set /apps/gnome-screensaver/idle_activation_enabled true
V-4084 No Change
Findings ID: GEN000800 Rule ID: SV-64321r2_rule Severity: medium CCI: CCI-000200

Discussion

If a user, or root, used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly.System Administrator

Checks

# ls /etc/security/opasswd
If /etc/security/opasswd does not exist, then this is a finding.

# grep password /etc/pam.d/system-auth| egrep '(pam_pwhistory.so|pam_unix.so|pam_cracklib.so)' | grep remember
If the "remember" option in /etc/pam.d/system-auth is not 5 or greater, this is a finding.

Check for system-auth-ac inclusions.
# grep -c system-auth-ac /etc/pam.d/*

If the system-auth-ac file is included anywhere
# more /etc/pam.d/system-auth-ac | grep password | egrep '(pam_pwhistory.so|pam_unix.so|pam_cracklib.so)' | grep remember

If in /etc/pam.d/system-auth-ac is referenced by another file and the "remember" option is not set to 5 or greater this is a finding.

Fix

Create the password history file.
# touch /etc/security/opasswd
# chown root:root /etc/security/opasswd
# chmod 0600 /etc/security/opasswd

Enable password history.
If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth to include the remember option on any "password pam_unix" or "password pam_pwhistory" lines set to at least 5.
V-4087 No Change
Findings ID: GEN001940 Rule ID: SV-63573r3_rule Severity: medium CCI: CCI-000225

Discussion

If start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to become trojans that destroy user files or otherwise compromise the system at the user, or higher, level. If the system is compromised at the user level, it is much easier to eventually compromise the system at the root and network level.System Administrator

Checks

Determine the world writable files on the system (Note: ignore all files under /proc):

# find / -perm -002 -a -type f -exec ls -ld {} \; | <more or redirect the output to a file>

# find / -perm -002 -a -type d -exec ls -ld {} \; | <more or redirect the output to a file>

View the password file to determine where the home directories for users are:

# more /etc/passwd

Once the directory for the human users is determined, grep for the lists of world writable files and directories within the users’ home directories.

An example would be:

# grep /opt/app/bin/daemon /home/*/.*

where /home is the directory for the human users on the system and /opt/app/bin/daemon is a world writable file.

Fix

Remove the world-writable permission of files referenced by local initialization scripts, or remove the references to these files in the local initialization scripts.
V-4089 No Change
Findings ID: GEN001660 Rule ID: SV-63857r1_rule Severity: medium CCI: CCI-000225

Discussion

System start-up files not owned by root could lead to system compromise by allowing malicious users or applications to modify them for unauthorized purposes. This could lead to system and network compromise.System Administrator

Checks

Check run control scripts' ownership.
# ls -lL /etc/rc* /etc/init.d

Alternatively:
# find /etc -name "[SK][0-9]*"|xargs stat -L -c %U:%n

If any run control script is not owned by root or bin, this is a finding.

Fix

Change the ownership of the run control script(s) with incorrect ownership.
# find /etc -name "[SK][0-9]*"|xargs stat -L -c %U:%n|egrep -v "^root:"|cut -d: -f2|xargs chown root
V-4090 No Change
Findings ID: GEN001680 Rule ID: SV-63859r1_rule Severity: medium CCI: CCI-000225

Discussion

If system start-up files do not have a group owner of root or a system group, the files may be modified by malicious users or intruders.System Administrator

Checks

Check run control scripts' group ownership.

Procedure:
# ls -lL /etc/rc* /etc/init.d

Alternatively:
# find /etc -name "[SK][0-9]*"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):"
If any run control script is not group-owned by root, sys, bin, or other system groups, this is a finding.

Fix

Change the group ownership of the run control script(s) with incorrect group ownership.

Procedure:
# chgrp root <run control script>
# find /etc -name "[SK][0-9]*"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):"|cut -d: -f2|xargs chgrp root
V-4091 No Change
Findings ID: GEN001700 Rule ID: SV-63861r1_rule Severity: medium CCI: CCI-000225

Discussion

System start-up files executing programs owned by other than root (or another privileged user) or an application indicating the system may have been compromised.System Administrator

Checks

Determine the programs executed by system start-up files. Determine the ownership of the executed programs.

# cat /etc/rc*/* /etc/init.d/* | more
# ls -l <executed program>

Alternatively:
# for FILE in `egrep -r "/" /etc/rc.* /etc/init.d|awk '/^.*[^\/][0-9A-Za-z_\/]*/{print $2}'|egrep "^/"|sort|uniq`;do if [ -e $FILE ]; then stat -L -c '%U:%n' $FILE;fi;done

This provides a list of files referenced by initialization scripts and their associated UIDs.
If any file is run by an initialization file and is not owned by root, sys, bin, or in rare cases, an application account, this is a finding.

Fix

Change the ownership of the file executed from system startup scripts to root, bin, sys, or other.
# chown root <executed file>
V-4246 No Change
Findings ID: GEN008620 Rule ID: SV-63135r1_rule Severity: medium CCI: CCI-000213

Discussion

A system's BIOS or system controller handles the initial startup of a system and its configuration must be protected from unauthorized modification. When the BIOS or system controller supports the creation of user accounts or passwords, such protections must be used and accounts/passwords only assigned to system administrators. Failure to protect BIOS or system controller settings could result in Denial of Service or compromise of the system resulting from unauthorized configuration changes.System Administrator

Checks

On systems with a BIOS or system controller, verify a supervisor or administrator password is set. If a password is not set, this is a finding.

If the BIOS or system controller supports user-level access in addition to supervisor/administrator access, determine if this access is enabled. If so, this is a finding.

Fix

Access the system's BIOS or system controller. Set a supervisor/administrator password if one has not been set. Disable a user-level password if one has been set.
V-4247 No Change
Findings ID: GEN008640 Rule ID: SV-63121r1_rule Severity: high CCI: CCI-000366

Discussion

Malicious users with removable boot media can gain access to a system configured to use removable media as the boot loader.System Administrator

Checks

Ask the SA if the system uses removable media for the boot loader. If it does, this is a finding.

Fix

Configure the system to use a bootloader installed on fixed media.
V-4248 No Change
Findings ID: GEN008660 Rule ID: SV-63115r1_rule Severity: high CCI: CCI-000366

Discussion

GRUB is a versatile boot loader used by several platforms that can provide authentication for access to the system or boot loader.System Administrator

Checks

Determine if the system uses the GRUB boot loader;

# ls -l /boot/grub/grub.conf

If no grub.conf file exists, and the bootloader on the system has not been authorized, justified, and documented, this is a finding.

Fix

Configure the system to use the GRUB bootloader or document, justify, and authorize the alternate bootloader.
V-4249 No Change
Findings ID: GEN008700 Rule ID: SV-63105r1_rule Severity: high CCI: CCI-000213

Discussion

If the system's boot loader does not require authentication, users with console access to the system may be able to alter the system boot configuration or boot the system into single user or maintenance mode, which could result in Denial of Service or unauthorized privileged access to the system.System Administrator

Checks

Check the "/boot/grub/grub.conf" or "/boot/grub/menu.lst" files.
# more /boot/grub/menu.lst

Check for a password configuration line, such as:
password --md5 <password-hash>

This line should be just below the line beginning with "timeout". Please note <password-hash> will be replaced by the actual MD5 encrypted password. If the password line is not in either of the files, this is a finding.

For any bootloader other than GRUB which has been authorized, justified and documented for use on the system refer to the vendor documentation on password support. If the bootloader does not support encrypted passwords, this is a finding.

Fix

The GRUB console boot loader can be configured to use an MD5 encrypted password by adding password --md5 password-hash to the "/boot/grub/grub.conf" file. Use "/sbin/grub-md5-crypt" to generate MD5 passwords from the command line.
V-4250 No Change
Findings ID: GEN008720 Rule ID: SV-63093r1_rule Severity: medium CCI: CCI-000225

Discussion

File permissions greater than 0600 on boot loader configuration files could allow an unauthorized user to view or modify sensitive information pertaining to system boot instructions.System Administrator

Checks

Check /boot/grub/grub.conf permissions:

# ls -lL /boot/grub/grub.conf

If /boot/grub/grub.conf has a mode more permissive than 0600, then this is a finding.

For any bootloader other than GRUB which has been authorized, justified and documented for use on the system refer to the vendor documentation for the location of the configuration file. If the bootloader configuration file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the grub.conf file to 0600.

# chmod 0600 /boot/grub/grub.conf
V-4255 No Change
Findings ID: GEN008680 Rule ID: SV-63107r1_rule Severity: high CCI: CCI-001208

Discussion

Storing the boot loader on removable media in an insecure location could allow a malicious user to modify the systems boot instructions or boot to an insecure operating system.System AdministratorInformation Assurance Officer

Checks

Ask the SA if the system boots from removable media. If so, ask if the boot media is stored in a secure container when not in use. If it is not, this is a finding.

Fix

Store the system boot media in a secure container when not in use.
V-4268 No Change
Findings ID: GEN000000-LNX00320 Rule ID: SV-62797r1_rule Severity: high CCI: CCI-000225

Discussion

If special privilege accounts are compromised, the accounts could provide privileges to execute malicious commands on a system.System Administrator

Checks

Perform the following to check for unnecessary privileged accounts:

# grep "^shutdown" /etc/passwd
# grep "^halt" /etc/passwd
# grep "^reboot" /etc/passwd

If any unnecessary privileged accounts exist this is a finding.

Fix

Remove any special privilege accounts, such as shutdown and halt, from the /etc/passwd and /etc/shadow files using the "userdel" or "system-config-users" commands.
V-4269 No Change
Findings ID: GEN000290 Rule ID: SV-63195r2_rule Severity: medium CCI: CCI-000012

Discussion

Accounts providing no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.System Administrator

Checks

Check the system for unnecessary user accounts.

Procedure:

# more /etc/passwd

Obtain a list of authorized accounts from the IAO. If any unnecessary accounts are found on the system, this is a finding.

Fix

Remove all unnecessary accounts from the /etc/passwd file before connecting a system to the network. Other accounts that are associated with a service not in use should also be removed.
V-4273 No Change
Findings ID: GEN006260 Rule ID: SV-63947r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the "incoming.conf" file may allow unauthorized modification which could lead to Denial-of-Service to authorized users or provide access to unauthorized users.System Administrator

Checks

The file corresponding to "/etc/news/hosts.nntp" is "/etc/news/incoming.conf". Check the permissions for "/etc/news/incoming.conf".

# ls -lL /etc/news/incoming.conf

If "/etc/news/incoming.conf" has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the "/etc/news/incoming.conf" file to 0600.

# chmod 0600 /etc/news/incoming.conf
V-4274 No Change
Findings ID: GEN006280 Rule ID: SV-63921r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the "" file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.System Administrator

Checks

The file that corresponds to "/etc/news/hosts.nntp.nolimit" is "/etc/news/infeed.conf".

Check the permissions for "/etc/news/infeed.conf".

# ls -lL /etc/news/infeed.conf

If "/etc/news/infeed.conf" has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of "/etc/news/infeed.conf" to 0600.

# chmod 0600 /etc/news/infeed.conf
V-4275 No Change
Findings ID: GEN006300 Rule ID: SV-63909r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the readers.conf file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.System Administrator

Checks

Check the permissions for "/etc/news/readers.conf".

# ls -lL /etc/news/readers.conf

If /etc/news/readers.conf has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the /etc/news/readers.conf file to 0600.
# chmod 0600 /etc/news/readers.conf
V-4276 No Change
Findings ID: GEN006320 Rule ID: SV-63899r1_rule Severity: medium CCI: CCI-000225

Discussion

File permissions more permissive than 0600 for "/etc/news/passwd.nntp" may allow access to privileged information by system intruders or malicious users.System Administrator

Checks

Check "/etc/news/passwd.nntp" permissions:

# ls -lL /etc/news/passwd.nntp

If "/etc/news/passwd.nntp" has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the "/etc/news/passwd.nntp" file.
# chmod 0600 /etc/news/passwd.nntp
V-4277 No Change
Findings ID: GEN006340 Rule ID: SV-63829r1_rule Severity: medium CCI: CCI-000225

Discussion

If critical system files are not owned by a privileged user, system integrity could be compromised.System Administrator

Checks

Check the ownership of the files in "/etc/news".

Procedure:
# ls -al /etc/news

If any files are not owned by root or news, this is a finding.

Fix

Change the ownership of the files in "/etc/news" to root or news.

Procedure:
# chown root /etc/news/*
V-4278 No Change
Findings ID: GEN006360 Rule ID: SV-63817r1_rule Severity: medium CCI: CCI-000225

Discussion

If critical system files do not have a privileged group-owner, system integrity could be compromised.System Administrator

Checks

Check "/etc/news" files group ownership:

Procedure:
# ls -al /etc/news

If "/etc/news" files are not group-owned by root or news, this is a finding.

Fix

Change the group-owner of the files in "/etc/news" to root or news.

Procedure:
# chgrp root /etc/news/*
V-4295 No Change
Findings ID: GEN005500 Rule ID: SV-63543r1_rule Severity: high CCI: CCI-001436

Discussion

SSHv1 is not a DoD-approved protocol and has many well-known vulnerability exploits. Exploits of the SSH daemon could provide immediate root access to the system.System Administrator

Checks

Locate the sshd_config file:
# more /etc/ssh/sshd_config

Examine the file. If the variables 'Protocol 2,1' or 'Protocol 1' are defined on a line without a leading comment, this is a finding.

If the SSH server is F-Secure, the variable name for SSH 1 compatibility is 'Ssh1Compatibility', not 'protocol'. If the variable 'Ssh1Compatiblity' is set to 'yes', then this is a finding.

Fix

Edit the sshd_config file and set the "Protocol" setting to "2".

If using the F-Secure SSH server, set the "Ssh1Compatibility" setting to "no".

Restart the SSH daemon.
# /sbin/service sshd restart
V-4298 No Change
Findings ID: GEN001000 Rule ID: SV-64393r1_rule Severity: medium CCI: CCI-000070

Discussion

The remote console feature provides an additional means of access to the system which could allow unauthorized access if not disabled or properly secured. With virtualization technologies, remote console access is essential as there is no physical console for virtual machines. Remote console access must be protected in the same manner as any other remote privileged access method.System Administrator

Checks

Check /etc/securetty
# more /etc/securetty
If the file does not exist, or contains more than "console" or a single "tty" device this is a finding.

Fix

Create if needed and set the contents of /etc/securetty to a "console" or "tty" device.
# echo console > /etc/securetty
or
# echo tty1 > /etc/securetty
V-4301 No Change
Findings ID: GEN000240 Rule ID: SV-63137r1_rule Severity: medium CCI: CCI-001492

Discussion

To assure the accuracy of the system clock, it must be synchronized with an authoritative time source within DoD. Many system functions, including time-based login and activity restrictions, automated reports, system logs, and audit records depend on an accurate system clock. If there is no confidence in the correctness of the system clock, time-based functions may not operate as intended and records may be of diminished value.

Authoritative time sources include authorized time servers within the enclave that synchronize with upstream authoritative sources. Specific requirements for the upstream synchronization of network time protocol (NTP) servers are covered in the Network Other Devices STIG.

For systems located on isolated or closed networks, it is not necessary to synchronize with a global authoritative time source. If a global authoritative time source is not available to systems on an isolated network, a local authoritative time source must be established on this network and used by the systems connected to this network. This is necessary to provide the ability to correlate events and allow for the correct operation of time-dependent protocols between systems on the isolated network.

If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events between systems will be necessary. If the system is completely isolated, this requirement is not applicable.System Administrator

Checks

Check if NTP running:
# ps -ef | egrep "xntpd|ntpd"

Check if "ntpd -qg" scheduled to run:
# grep "ntpd -qg" /var/spool/cron/*
# grep "ntpd -qg" /etc/cron.d/*
# grep "ntpd -qg" /etc/cron.daily/*
# grep "ntpd -qg" /etc/cron.hourly/*
# grep "ntpd -qg" /etc/cron.monthly/*
# grep "ntpd -qg" /etc/cron.weekly/*

If NTP is running or "ntpd -qg" is found:

# more /etc/ntp.conf

Confirm the timeservers and peers or multicast client (as applicable) are local or authoritative U.S. DoD sources appropriate for the level of classification which the network operates.

If a non-local/non-authoritative time-server is used, this is a finding.

Fix

Use an authoritative local time server or a time server operated by the U.S. government. Ensure all systems in the facility feed from one or more local time servers which feed from the authoritative U.S. government time server.
V-4304 No Change
Findings ID: GEN003640 Rule ID: SV-64225r1_rule Severity: medium CCI: CCI-000553

Discussion

File system journaling, or logging, can allow reconstruction of file system data after a system crash, preserving the integrity of data that may have otherwise been lost. Journaling file systems typically do not require consistency checks upon booting after a crash, which can improve system availability. Some file systems employ other mechanisms to ensure consistency also satisfying this requirement.System Administrator

Checks

Logging should be enabled for those types of file systems not turning on logging by default.

Procedure:
# mount

JFS, VXFS, HFS, XFS, reiserfs, EXT3 and EXT4 all turn logging on by default and will not be a finding. The ZFS file system uses other mechanisms to provide for file system consistency, and will not be a finding. For other file systems types, if the root file system does not support journaling this is a finding. If the 'nolog' option is set on the root file system that does support journaling, this is a finding.

Fix

Implement file system journaling for the root file system, or use a file system with other mechanisms to ensure file system consistency. If the root file system supports journaling, enable it. If the file system does not support journaling or another mechanism to ensure file system consistency, a migration to a different file system will be necessary.
V-4321 No Change
Findings ID: GEN006060 Rule ID: SV-64125r1_rule Severity: medium CCI: CCI-001436

Discussion

Samba is a tool used for the sharing of files and printers between Windows and UNIX operating systems. It provides access to sensitive files and, therefore, poses a security risk if compromised.System Administrator

Checks

Check the system for a running Samba server.

Procedure:
# ps -ef |grep smbd

If the Samba server is running, ask the SA if the Samba server is operationally required. If it is not, this is a finding.

Fix

If there is no functional need for Samba and the daemon is running, disable the daemon by killing the process ID as noted from the output of ps -ef |grep smbd. The samba package should also be removed or not installed if there is no functional requirement.

Procedure:
rpm -qa |grep samba

This will show whether "samba" or "samba3x" is installed. To remove:

rpm --erase samba
or
rpm --erase samba3x
V-4334 No Change
Findings ID: GEN000000-LNX00480 Rule ID: SV-62929r1_rule Severity: medium CCI: CCI-000225

Discussion

The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security.System Administrator

Checks

Check /etc/sysctl.conf ownership.
# ls -lL /etc/sysctl.conf
If /etc/sysctl.conf is not owned by root, this is a finding.

Fix

Use the chown command to change the owner of /etc/sysctl.conf to root:
# chown root /etc/sysctl.conf
V-4335 No Change
Findings ID: GEN000000-LNX00500 Rule ID: SV-62951r1_rule Severity: medium CCI: CCI-000225

Discussion

The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security.System Administrator

Checks

Check /etc/sysctl.conf group ownership:
# ls -lL /etc/sysctl.conf
If /etc/sysctl.conf is not group-owned by root, this is a finding.

Fix

Use the chgrp command to change the group owner of /etc/sysctl.conf to root:
# chgrp root /etc/sysctl.conf
V-4336 No Change
Findings ID: GEN000000-LNX00520 Rule ID: SV-62963r1_rule Severity: medium CCI: CCI-000225

Discussion

The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security.System Administrator

Checks

Check /etc/sysctl.conf permissions:

# ls -lL /etc/sysctl.conf

If /etc/sysctl.conf has a mode more permissive than 0600, this is a finding.

Fix

Use the chmod command to change the mode of the /etc/sysctl.conf file.
# chmod 0600 /etc/sysctl.conf
V-4339 No Change
Findings ID: GEN000000-LNX00560 Rule ID: SV-62985r1_rule Severity: high CCI: CCI-000225

Discussion

Insecure file locking could allow for sensitive data to be viewed or edited by an unauthorized user.System Administrator

Checks

Determine if an NFS server is running on the system by:

# ps -ef |grep nfsd

If an NFS server is running, confirm it is not configured with the insecure_locks option by:

# exportfs -v

The example below would be a finding:

/misc/export speedy.example.com(rw,insecure_locks)

Fix

Remove the "insecure_locks" option from all NFS exports on the system.

Procedure:

Edit /etc/exports and remove all instances of the insecure_locks option.

Re-export the file systems to make the setting take effect.
# exportfs -a
V-4342 No Change
Findings ID: GEN000000-LNX00580 Rule ID: SV-62991r1_rule Severity: high CCI: CCI-000366

Discussion

Undesirable reboots can occur if the CTRL-ALT-DELETE key sequence is not disabled. Such reboots may cause a loss of data or loss of access to critical information.System Administrator

Checks

Verify that reboot using the CTRL-ALT-DELETE key sequence has been disabled by performing:

# grep ctrlaltdel /etc/inittab

If the line returned does not specify "/usr/bin/logger", or is not commented out, this is a finding.

Fix

Ensure the CTRL-ALT-DELETE key sequence has been disabled and attempts to use the sequence are logged.
In the /etc/inittab file replace:
ca::ctrlaltdel:/sbin/shutdown -t3 -r now
with
ca:nil:ctrlaltdel:/usr/bin/logger -p security.info "Ctrl-Alt-Del was pressed"

Once this change has been made, execute the following command to force the "init" daemon to re-read /etc/inittab:

# telinit q
V-4346 No Change
Findings ID: GEN000000-LNX00600 Rule ID: SV-63003r1_rule Severity: medium CCI: CCI-000225

Discussion

If an unauthorized user has been granted privileged access while logged in at the console, the security posture of a system could be greatly compromised. Additionally, such a situation could deny legitimate root access from another terminal.System Administrator

Checks

Ensure the pam_console.so module is not configured in any files in /etc/pam.d by:

# cd /etc/pam.d
# grep pam_console.so *

Or

# ls -la /etc/security/console.perms

If either the pam_console.so entry or the file /etc/security/console.perms is found then this is a finding.

Fix

Configure PAM to not grant sole access of administrative privileges to the first user logged in at the console.

Identify any instances of pam_console.

# cd /etc/pam.d
# grep pam_console.so *

For any files containing an un-commented reference to pam_console.so, edit the file and remove or comment out the reference.

Remove the console.perms file if it exists:
# rm /etc/security/console.perms
V-4357 No Change
Findings ID: GEN002860 Rule ID: SV-64423r1_rule Severity: medium CCI: CCI-000366

Discussion

Rotate audit logs daily to preserve audit file system space and to conform to the DoD/DISA requirement. If it is not rotated daily and moved to another location, then there is more of a chance for the compromise of audit data by malicious users.System Administrator

Checks

Check for any crontab entries that rotate audit logs.

Procedure:
# crontab -l
If such a cron job is found, this is not a finding.

Otherwise, query the SA. If there is a process automatically rotating audit logs, this is not a finding.

If the SA manually rotates audit logs, this is a finding, because if the SA is not there, it will not be accomplished.

If the audit output is not archived daily, to tape or disk, this is a finding.

This can be ascertained by looking at the audit log directory and, if more than one file is there, or if the file does not have today's date, this is a finding.

Fix

Configure a cron job or other automated process to rotate the audit logs on a daily basis.
V-4358 No Change
Findings ID: GEN003200 Rule ID: SV-64329r1_rule Severity: medium CCI: CCI-000225

Discussion

If file permissions for cron.deny are more permissive than 0600, sensitive information could be viewed or edited by unauthorized users.System Administrator

Checks

Check the mode of the cron.deny file.
# ls -lL /etc/cron.deny
If the cron.deny file does not exist this is not a finding.
If the cron.deny file exists and the mode is more permissive than 0600, this is a finding.

Fix

Change the mode of the cron.deny file.
# chmod 0600 /etc/cron.deny
V-4360 No Change
Findings ID: GEN003220 Rule ID: SV-64337r2_rule Severity: low CCI: CCI-000225

Discussion

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit octal number, the first digit representing special access modes is typically ignored or required to be 0.trueIf a cron program sets the umask to 000 or does not restrict the world-writable permission, this becomes a CAT I finding.System Administrator

Checks

Determine if there are any crontabs by viewing a long listing of the directory. If there are crontabs, examine them to determine what cron jobs exist. Check for any programs specifying a umask more permissive than 077:

Procedure:

# ls -lL /var/spool/cron

# ls -lL /etc/cron.d /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -lL /etc/cron.*|grep -v deny

# cat <crontab file>
# grep umask <cron program>

If there are no cron jobs present, this vulnerability is not applicable. If any cron job contains a umask more permissive than 077, this is a finding.

Fix

Edit cron script files and modify the umask to 077.
V-4361 No Change
Findings ID: GEN003240 Rule ID: SV-64343r1_rule Severity: medium CCI: CCI-000225

Discussion

If the owner of the cron.allow file is not set to root, bin, or sys, the possibility exists for an unauthorized user to view or to edit sensitive information.System Administrator

Checks

# ls -lL /etc/cron.allow
If the cron.allow file is not owned by root, sys, or bin, this is a finding.

Fix

# chown root /etc/cron.allow
V-4364 No Change
Findings ID: GEN003400 Rule ID: SV-64287r1_rule Severity: medium CCI: CCI-000225

Discussion

If the "at" directory has a mode more permissive than 0755, unauthorized users could be allowed to view or to edit files containing sensitive information within the "at" directory. Unauthorized modifications could result in Denial of Service to authorized "at" jobs.System Administrator

Checks

Check the mode of the "at" directory.

Procedure:
# ls -ld /var/spool/at

If the directory mode is more permissive than 0755, this is a finding.

Fix

Change the mode of the "at" directory to 0755.

Procedure:
# chmod 0755 <at directory>
V-4365 No Change
Findings ID: GEN003420 Rule ID: SV-64299r2_rule Severity: medium CCI: CCI-000225

Discussion

If the owner of the "at" directory is not root, bin, or sys, unauthorized users could be allowed to view or edit files containing sensitive information within the directory.System Administrator

Checks

Check the ownership of the "at" directory:

Procedure:
# ls -ld /var/spool/at

If the directory is not owned by root, sys, bin, daemon, or cron, this is a finding.

Fix

Change the owner of the "at" directory to root, bin, sys, or system.

Procedure:
# chown <root or other system account> <"at" directory>
V-4366 No Change
Findings ID: GEN003440 Rule ID: SV-64409r1_rule Severity: medium CCI: CCI-000225

Discussion

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0.trueSystem AdministratorInformation Assurance Officer

Checks

Determine what "at" jobs exist on the system.
Procedure:
# ls /var/spool/at

If there are no "at" jobs present, this is not applicable.

Determine if any of the "at" jobs or any scripts referenced execute the "umask" command. Check for any umask setting more permissive than 077.

# grep umask <at job or referenced script>

If any "at" job or referenced script sets umask to a value more permissive than 077, this is a finding.

Fix

Edit "at" jobs or referenced scripts to remove "umask" commands that set umask to a value less restrictive than 077.
V-4367 No Change
Findings ID: GEN003460 Rule ID: SV-64319r1_rule Severity: medium CCI: CCI-000225

Discussion

If the owner of the at.allow file is not set to root, bin, or sys, unauthorized users could be allowed to view or edit sensitive information contained within the file.System Administrator

Checks

# ls -lL /etc/at.allow
If the at.allow file is not owned by root, sys, or bin, this is a finding.

Fix

Change the owner of the at.allow file.
# chown root /etc/at.allow
V-4368 No Change
Findings ID: GEN003480 Rule ID: SV-64417r1_rule Severity: medium CCI: CCI-000225

Discussion

If the owner of the at.deny file is not set to root, bin, or sys, unauthorized users could be allowed to view or edit sensitive information contained within the file.System Administrator

Checks

# ls -lL /etc/at.deny
If the at.deny file is not owned by root, sys, or bin, this is a finding.

Fix

Change the owner of the at.deny file.
# chown root /etc/at.deny
V-4369 No Change
Findings ID: GEN003960 Rule ID: SV-63487r1_rule Severity: medium CCI: CCI-000225

Discussion

If the traceroute command owner has not been set to root, an unauthorized user could use this command to obtain knowledge of the network topology inside the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise.System Administrator

Checks

# ls -lL /bin/traceroute
If the traceroute command is not owned by root, this is a finding.

Fix

Change the owner of the traceroute command to root.
Example:
# chown root /bin/traceroute
V-4370 No Change
Findings ID: GEN003980 Rule ID: SV-63511r1_rule Severity: medium CCI: CCI-000225

Discussion

If the group owner of the traceroute command has not been set to a system group, unauthorized users could have access to the command and use it to gain information regarding a network's topology inside of the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise.System Administrator

Checks

Check the group ownership of the traceroute file.

Procedure:
# ls -lL /bin/traceroute

If the traceroute command is not group-owned by root, sys, bin, or system, this is a finding.

Fix

Change the group-owner of the traceroute command to root.

Procedure:
# chgrp root /bin/traceroute
V-4371 No Change
Findings ID: GEN004000 Rule ID: SV-63525r1_rule Severity: medium CCI: CCI-000225

Discussion

If the mode of the traceroute executable is more permissive than 0700, malicious code could be inserted by an attacker and triggered whenever the traceroute command is executed by authorized users. Additionally, if an unauthorized user is granted executable permissions to the traceroute command, it could be used to gain information about the network topology behind the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise.System Administrator

Checks

# ls -lL /bin/traceroute
If the traceroute command has a mode more permissive than 0700, this is a finding.

Fix

Change the mode of the traceroute command.
# chmod 0700 /bin/traceroute
V-4382 No Change
Findings ID: GEN004220 Rule ID: SV-63545r1_rule Severity: high CCI: CCI-000225

Discussion

If a web browser flaw is exploited while running as a privileged user, the entire system could be compromised.

Specific exceptions for local service administration should be documented in site-defined policy. These exceptions may include HTTP(S)-based tools used for the administration of the local system, services, or attached devices. Examples of possible exceptions are HP's System Management Homepage (SMH), the CUPS administrative interface, and Sun's StorageTek Common Array Manager (CAM) when these services are running on the local system.System Administrator

Checks

Look in the root account home directory for a .mozilla directory. If none exists, this is not a finding. If there is one, verify with the root users and the IAO the intent of the browsing. If the browsing is not limited to authorized local services administration, this is a finding.

Fix

Enforce policy requiring administrative accounts use web browsers only for local service administration.
V-4384 No Change
Findings ID: GEN004560 Rule ID: SV-63771r1_rule Severity: low CCI: CCI-000366

Discussion

The version of the SMTP service can be used by attackers to plan an attack based on vulnerabilities present in the specific version.System Administrator

Checks

To check for the version of either sendmail or Postfix being displayed in the greeting:

# telnet localhost 25

If a version number is displayed, this is a finding.

Fix

Ensure sendmail or Postfix has been configured to mask the version information.

Procedure
for sendmail:
Change the O SmtpGreetingMessage line in the /etc/mail/sendmail.cf file as noted below:
O SmtpGreetingMessage=$j Sendmail $v/$Z; $b
change it to:
O SmtpGreetingMessage= Mail Server Ready ; $b

for Postfix:
Examine the "smtpd_banner" line of /etc/postfix/main.conf and remove any "$mail_version" entry on it or comment the entire "smtpd_banner" line to use the default value which does not display the version information.
V-4385 No Change
Findings ID: GEN004580 Rule ID: SV-62713r2_rule Severity: medium CCI: CCI-000366

Discussion

The .forward file allows users to automatically forward mail to another system. Use of .forward files could allow the unauthorized forwarding of mail and could potentially create mail loops which could degrade system performance.System Administrator

Checks

Check forwarding capability from sendmail.

Procedure:
grep "O ForwardPath" /etc/mail/sendmail.cf

If the entry contains a file path, this is a finding.

Search for any .forward in users home directories on the system by:

# for pwline in `cut -d: -f1,6 /etc/passwd`; do homedir=`echo ${pwline}|cut -d: -f2`;username=`echo ${pwline} | cut -d: -f1`;echo $username `stat -c %n $homedir/.forward 2>null`; done|egrep "\.forward"

If any users have a .forward file in their home directory, this is a finding.

Fix

Disable forwarding for sendmail and remove .forward files from the system

Procedure:
Edit the /etc/mail/sendmail.mc file to change the ForwardPath entry to a null path by adding the line
define(`confFORWARD_PATH',`')
rebuild the sendmail.cf file.

Remove all .forward files on the system
# find / -name .forward -delete
V-4387 No Change
Findings ID: GEN005000 Rule ID: SV-63109r1_rule Severity: high CCI: CCI-000225

Discussion

If an anonymous FTP account has been configured to use a functional shell, attackers could gain access to the shell if the account is compromised.System Administrator

Checks

Check the shell for the anonymous FTP account.

Procedure:
# grep "^ftp" /etc/passwd

This is a finding if the seventh field is empty (the entry ends with a ':') or if the seventh field does not contain one of the following:

/bin/false
/dev/null
/usr/bin/false
/bin/true
/sbin/nologin

Fix

Configure anonymous FTP accounts to use a non-functional shell. If necessary, edit the /etc/passwd file to remove any functioning shells associated with the ftp account and replace them with non-functioning shells, such as /dev/null.
V-4392 No Change
Findings ID: GEN005380 Rule ID: SV-63465r1_rule Severity: medium CCI: CCI-001208

Discussion

Installing extraneous software on a system designated as a dedicated Network Management System (NMS) server poses a security threat to the system and the network. Should an attacker gain access to the NMS through unauthorized software, the entire network may be susceptible to malicious activity.System Administrator

Checks

Ask the SA if this is an NMS server. If it is an NMS server, then ask what other applications run on it. If there is anything other than network management software and DBMS software used only for the storage and inquiry of NMS data, this is a finding.

Fix

Ensure only authorized software is loaded on a designated NMS server. Authorized software is limited to the NMS software itself, a database management system for the NMS server if necessary, and network management software.
V-4393 No Change
Findings ID: GEN005400 Rule ID: SV-63473r2_rule Severity: medium CCI: CCI-000225

Discussion

If the /etc/syslog.conf file is not owned by root, unauthorized users could be allowed to view, edit, or delete important system messages handled by the syslog facility.System Administrator

Checks

Check /etc/syslog.conf or /etc/rsyslog.conf ownership:

For syslog:

# ls -lL /etc/syslog.conf

For rsyslog:

# ls -lL /etc/rsyslog.conf

If /etc/syslog.conf or /etc/rsyslog.conf is not owned by root, this is a finding.

Fix

Use the chown command to set the owner to root.

# chown root /etc/syslog.conf

Or:

# chown root /etc/rsyslog.conf
V-4394 No Change
Findings ID: GEN005420 Rule ID: SV-65303r2_rule Severity: medium CCI: CCI-000225

Discussion

If the group owner of /etc/syslog.conf is not root, bin, or sys, unauthorized users could be permitted to view, edit, or delete important system messages handled by the syslog facility.System Administrator

Checks

Check /etc/syslog.conf or /etc/rsyslog.conf group ownership.

Procedure:

# ls -lL /etc/syslog.conf

Or:

# ls -lL /etc/syslog.conf

If /etc/syslog.conf or /etc/rsyslog.conf is not group owned by root, sys, bin, or system, this is a finding.

Fix

Procedure:

# chgrp root /etc/syslog.conf

Or

# chgrp root /etc/rsyslog.conf
V-4395 No Change
Findings ID: GEN005460 Rule ID: SV-63507r2_rule Severity: medium CCI: CCI-000366

Discussion

If a remote log host is in use and it has not been justified and documented with the IAO, sensitive information could be obtained by unauthorized users without the SA's knowledge. A remote log host is any host to which the system is sending syslog messages over a network.trueSystem AdministratorInformation Assurance Officer

Checks

Examine the syslog.conf or rsyslog.conf file for any references to remote log hosts.

# grep -v "^#" /etc/syslog.conf | grep '@'

Or:

# grep -v "^#" /etc/rsyslog.conf | grep '@'

Destination locations beginning with an '@' represent log hosts.

If the log host name is a local alias such as "loghost", consult the /etc/hosts or other name databases as necessary to obtain the canonical name or address for the log host.

Determine if the host referenced is a log host documented using site-defined procedures.

If an undocumented log host is referenced, this is a finding.

Fix

Remove or document the referenced undocumented log host.
V-4397 No Change
Findings ID: GEN005560 Rule ID: SV-64105r1_rule Severity: medium CCI: CCI-000366

Discussion

If a system has no default gateway defined, the system is at increased risk of man-in-the-middle, monitoring, and Denial of Service attacks.System Administrator

Checks

Check the system for an IPv4 default route. If the system is a VM host and acts as a router solely for the benefit of its client systems, then this rule is not applicable.

Procedure:
# netstat -r |grep default

If a default route is not defined, this is a finding.

Fix

Set a default gateway for IPv4.
V-4398 No Change
Findings ID: GEN005580 Rule ID: SV-64109r2_rule Severity: medium CCI: CCI-001208

Discussion

Installing extraneous software on a system designated as a dedicated router poses a security threat to the system and the network. Should an attacker gain access to the router through the unauthorized software, the entire network is susceptible to malicious activity.System Administrator

Checks

If the system is a VM host and acts as a router solely for the benefit of its client systems, then this rule is not applicable.

Check to see if the system is a router:

# chkconfig --list | grep :on | egrep '(ospf|route|bgp|zebra|quagga)'

If the system is running a routing service, it is a router.

If it is not, this is not applicable.

Check the system for non-routing network services.

Procedure:

# netstat -a | grep -i listen
# ps -ef

If non-routing services, including Web servers, file servers, DNS servers, or applications servers, but excluding management services such as SSH and SNMP, are running on the system, this is a finding.

Fix

Ensure only authorized software is loaded on a designated router. Authorized software will be limited to the most current version of routing protocols and SSH for system administration purposes.
V-4399 No Change
Findings ID: GEN006380 Rule ID: SV-63813r1_rule Severity: high CCI: CCI-001436

Discussion

Implementing Network Information Service (NIS) or NIS+ under UDP may make the system more susceptible to a Denial of Service attack and does not provide the same quality of service as TCP.System Administrator

Checks

If the system does not use NIS or NIS+, this is not applicable.

Check if NIS or NIS+ is implemented using UDP.

Procedure:
# rpcinfo -p | grep yp | grep udp

If NIS or NIS+ is implemented using UDP, this is a finding.

Fix

Configure the system to not use UDP for NIS and NIS+. Consult vendor documentation for the required procedure.
V-4427 No Change
Findings ID: GEN002020 Rule ID: SV-63611r1_rule Severity: medium CCI: CCI-000366

Discussion

If these files are not properly configured, they could allow malicious access by unknown malicious users from untrusted hosts who could compromise the system.System Administrator

Checks

Locate and examine all r-commands access control files.

Procedure:
# find / -name .rhosts
# more /<directorylocation>/.rhosts

# find / -name .shosts
# more /<directorylocation>/.shosts

# find / -name hosts.equiv
# more /<directorylocation>/hosts.equiv

# find / -name shosts.equiv
# more /<directorylocation>/shosts.equiv

If any .rhosts, .shosts, hosts.equiv, or shosts.equiv file contains other than host-user pairs, this is a finding.

Fix

If possible, remove the .rhosts, .shosts, hosts.equiv, and shosts.equiv files. If the files are required, remove any content from the files except for necessary host-user pairs.
V-4428 No Change
Findings ID: GEN002060 Rule ID: SV-63635r1_rule Severity: medium CCI: CCI-000225

Discussion

If these files are accessible by users other than root or the owner, they could be used by a malicious user to set up a system compromise.System Administrator

Checks

Procedure:
# ls -l /etc/hosts.equiv

# ls -l /etc/ssh/shosts.equiv

# find / -name .rhosts
# ls -al <home directory>/.rhosts

# find / -name .shosts
# ls -al <home directory>/.shosts

# find / -name .netrc
# ls -al <home directory>/.netrc

If the .rhosts, .shosts, hosts.equiv, or shosts.equiv files have permissions greater than 600, then this is a finding.
If the /etc/hosts.equiv, or /etc/ssh/shosts.equiv files are not owned by root, this is a finding.

Any .rhosts, .shosts and .netrc files outside of home directories have no meaning and are not subject to this rule
If the ~/.rhosts or ~/.shosts are not owned by the owner of the home directory where they are immediately located or by root, this is a finding.

Fix

Ensure the permission for these files is set to 600 or more restrictive and their owner is root or the same as the owner of the home directory in which they reside.

Procedure:
# chmod 600 /etc/hosts.equiv
# chmod 600 /etc/ssh/shosts.equiv
# chown root /etc/hosts.equiv
# chown root /etc/ssh/shosts.equiv

# find / -name .rhosts
# chmod 600 /<home directory>/.rhosts
# chown <home directory owner> <home directory>/.rhosts

# find / -name .shosts
# chmod 600 <directory location>/.shosts
# chown <home directory owner> <home directory>/.shosts

# find / -name .netrc
# chmod 600 <directory location>/.netrc
# chown <home directory owner> <home directory>/.netrc
V-4430 No Change
Findings ID: GEN003260 Rule ID: SV-64361r1_rule Severity: medium CCI: CCI-000225

Discussion

Cron daemon control files restrict the scheduling of automated tasks and must be protected.
System Administrator

Checks

# ls -lL /etc/cron.deny
If the cron.deny file is not owned by root, sys, or bin, this is a finding.

Fix

# chown root /etc/cron.deny
V-4687 No Change
Findings ID: GEN003820 Rule ID: SV-64011r1_rule Severity: high CCI: CCI-000068

Discussion

The rshd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.System AdministratorInformation Assurance Officer

Checks

Check to see if rshd is configured to run on startup.

Procedure:
# grep disable /etc/xinetd.d/rsh

If /etc/xinetd.d/rsh exists and rsh is found to be enabled, this is a finding.

Fix

Edit /etc/xinetd.d/rsh and set "disable=yes".
V-4688 No Change
Findings ID: GEN003840 Rule ID: SV-64037r1_rule Severity: high CCI: CCI-001435

Discussion

The rexecd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.trueSystem AdministratorInformation Assurance Officer

Checks

# grep disable /etc/xinetd.d/rexec
If the service file exists and is not disabled, this is a finding.

Fix

Edit /etc/xinetd.d/rexec and set "disable=yes"
V-4689 No Change
Findings ID: GEN004600 Rule ID: SV-62907r2_rule Severity: high CCI: CCI-001230

Discussion

The SMTP service version on the system must be current to avoid exposing vulnerabilities present in unpatched versions.System Administrator

Checks

Determine the version of the SMTP service software.

Procedure:
# rpm -q sendmail

sendmail-8.13.8-10 is the latest required version. If sendmail is installed and the version is not at least 8.13.8-10, this is a finding.

# rpm -q postfix

postfix-2.3.3-7.el5 is the latest required version. If the postfix is installed and the version is not at least 2:2.3.3-7, this is a finding.

Fix

Obtain and install a newer version of the SMTP service software (sendmail or Postfix) from the operating system vendor.
V-4690 No Change
Findings ID: GEN004620 Rule ID: SV-62813r1_rule Severity: high CCI: CCI-000366

Discussion

Debug mode is a feature present in older versions of sendmail which, if not disabled, may allow an attacker to gain access to a system through the sendmail service.System Administrator

Checks

Check for an enabled "debug" command provided by the SMTP service.

Procedure:
# telnet localhost 25
debug

If the command does not return a 500 error code of "command unrecognized" or a 550 error code of "access denied", this is a finding.

The operating system distribution ships with sendmail Version 8.13.8 which is not vulnerable. This should never be a finding.

Fix

Obtain and install a newer version of the SMTP service software (sendmail or Postfix) from the operating system vendor.
V-4691 No Change
Findings ID: GEN004640 Rule ID: SV-62821r1_rule Severity: high CCI: CCI-001230

Discussion

A common configuration for older Mail Transfer Agents (MTAs) is to include an alias for the decode user. All mail sent to this user is sent to the uudecode program, which automatically converts and stores files. By sending mail to the decode or the uudecode aliases present on some systems, a remote attacker may be able to create or overwrite files on the remote host. This could possibly be used to gain remote access.System Administrator

Checks

Check the SMTP service for an active "decode" command.

Procedure:
# telnet localhost 25
decode

If the command does not return a 500 error code of "command unrecognized", this is a finding.

Fix

Disable mail aliases for decode and uudecode. If the /etc/aliases or /usr/lib/aliases (mail alias) file contains entries for these programs, remove them or disable them by placing "#" at the beginning of the line, and then executing the new aliases command. For more information on mail aliases, refer to the man page for aliases. Disabled aliases would be similar to these examples:

# decode: |/usr/bin/uudecode
# uudecode: |/usr/bin/uuencode -d
V-4692 No Change
Findings ID: GEN004660 Rule ID: SV-62833r1_rule Severity: low CCI: CCI-000366

Discussion

The SMTP EXPN function allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. EXPN may also provide additional information concerning users on the system, such as the full names of account owners.False positives may occur with the SMTP EXPN check. According to RFC821, it is acceptable for a server to respond with a 250 (success) or 550 (failure) when the server supports the EXPN command. For example, some servers return 550 EXPN command not available, meaning the command is not supported and the machine is not vulnerable. However, a result of 550 that is a mailing list, not a user would be a failure code, but not an indication of an error, and the machine would be vulnerable. If a false positive is suspected, check the log file for the response from the server.System Administrator

Checks

This vulnerability is applicable only to sendmail. If Postfix is the SMTP service for the system this will never be a finding.

Procedure:
Determine if EXPN is disabled.
# grep -v "^#" /etc/mail/sendmail.cf |grep -i PrivacyOptions

If nothing is returned or the returned line does not contain "noexpn", this is a finding.

Fix

Rebuild /etc/mail/sendmail.cf with the "noexpn" Privacy Flag set.

Procedure:
Edit /etc/mail/sendmail.mc resetting the Privacy Flags to the default:

define('confPRIVACYFLAGS', 'authwarnings,novrfy,noexpn,restrictqrun')dnl

Rebuild the sendmail.cf file with:
# make -C /etc/mail

Restart the sendmail service.
# service sendmail restart
V-4693 No Change
Findings ID: GEN004680 Rule ID: SV-62859r1_rule Severity: low CCI: CCI-000366

Discussion

The VRFY command allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. VRFY may provide additional information about users on the system, such as the full names of account owners.System Administrator

Checks

Determine if VRFY is disabled.

Procedure:
# telnet localhost 25
vrfy root

If the command does not return a 500 error code of "command unrecognized", this is a finding.

or:
# grep -v "^#" /etc/mail/sendmail.cf |grep -i vrfy

Verify the VRFY command is disabled with an entry in the sendmail.cf file. The entry could be any one of "Opnovrfy", "novrfy", or "goaway", which could also have other options included, such as "noexpn". The "goaway" argument encompasses many things, such as "novrfy" and "noexpn".

If no setting to disable VRFY is found, this is a finding.

Fix

Add the "novrfy" flag to your sendmail in /etc/mail/sendmail.cf.

Procedure:
Edit the definition of "confPRIVACY_FLAGS" in /etc/mail/sendmail.mc to include "novrfy".

Rebuild the sendmail.cf file with:
# make -C /etc/mail

Restart the sendmail service.
# service sendmail restart
V-4694 No Change
Findings ID: GEN004700 Rule ID: SV-62867r1_rule Severity: low CCI: CCI-000366

Discussion

Very old installations of the Sendmail mailing system contained a feature whereby a remote user connecting to the SMTP port can enter the WIZ command and be given an interactive shell with root privileges.System Administrator

Checks

Log into the sendmail server with telnet and test the "wiz" command.

Procedure:
# telnet localhost 25

Trying 127.0.0.1...
Connected to locahost.localdomain (127.0.0.1).
Escape character ...

Once the telnet greeting is complete type:
wiz

If you do not get a "Command unrecognized: " message, this is a finding.

Fix

If the WIZ command exists on sendmail then the version of sendmail is archaic and should be replaced with the latest version from the operating system vendor. WIZ is not available on any sendmail distribution delivered by this operating system.

However, if the WIZ command is enabled on sendmail, it should be disabled by adding this line to the sendmail.cf configuration file (note that it must be typed in uppercase):

OW*

For the change to take effect, kill the sendmail process, refreeze the sendmail.cf file, and restart the sendmail process.
V-4695 No Change
Findings ID: GEN005140 Rule ID: SV-63167r1_rule Severity: high CCI: CCI-000225

Discussion

TFTP is a file transfer protocol often used by embedded systems to obtain configuration data or software. The service is unencrypted and does not require authentication of requests. Data available using this service may be subject to unauthorized access or interception.System AdministratorInformation Assurance Officer

Checks

Determine if the TFTP daemon is active.
# chkconfig --list | grep tftp

If TFTP is found enabled ("on") and not documented using site-defined procedures, it is a finding.

Fix

Document or Disable the TFTP daemon.

If the TFTP daemon is necessary on the system, document and justify its usage for approval from the IAO.

If the TFTP daemon is not necessary on the system, turn it off.

# chkconfig tftp off
# service xinetd restart
V-4696 No Change
Findings ID: GEN005280 Rule ID: SV-63353r1_rule Severity: medium CCI: CCI-001436

Discussion

The UUCP utility is designed to assist in transferring files, executing remote commands, and sending e-mail between UNIX systems over phone lines and direct connections between systems. The UUCP utility is a primitive and arcane system with many security issues. There are alternate data transfer utilities/products that can be configured to more securely transfer data by providing for authentication as well as encryption.System Administrator

Checks

# service uucp status
if UUCP is "running", this is a finding.

Fix

# chkconfig uucp off
# service uucp stop
# service xinetd restart
V-4697 No Change
Findings ID: GEN005200 Rule ID: SV-63295r1_rule Severity: high CCI: CCI-000225

Discussion

Open X displays allow an attacker to capture keystrokes and to execute commands remotely. Many users have their X Server set to "xhost +", permitting access to the X Server by anyone, from anywhere.System Administrator

Checks

If Xwindows is not used on the system, this is not applicable.

Check the output of the "xhost" command from an X terminal.

Procedure:
# xhost
If the output reports access control is enabled (and possibly lists the hosts able to receive X window logins), this is not a finding. If the xhost command returns a line indicating access control is disabled, this is a finding.

Note: It may be necessary to define the display if the command reports it cannot open the display.

Procedure:
$ DISPLAY=MachineName:0.0; export DISPLAY
MachineName may be replaced with an Internet Protocol Address. Repeat the check procedure after setting the display.

Fix

If using an xhost-type authentication the "xhost -" command can be used to remove current trusted hosts and then selectively allow only trusted hosts to connect with "xhost +" commands. A cryptographically secure authentication, such as provided by the xauth program, is always preferred.

Refer to your X11 server's documentation for further security information.
V-4701 No Change
Findings ID: GEN003860 Rule ID: SV-64051r1_rule Severity: low CCI: CCI-001551

Discussion

The finger service provides information about the system's users to network clients. This information could expose more information for potential used in subsequent attacks.System Administrator

Checks

# grep disable /etc/xinetd.d/finger
If the finger service is not disabled, this is a finding.

Fix

Edit /etc/xinetd.d/finger and set "disable=yes"
V-4702 No Change
Findings ID: GEN004840 Rule ID: SV-62925r1_rule Severity: medium CCI: CCI-000787

Discussion

Anonymous FTP is a public data service which is only permitted in a server capacity when located on the DMZ network.System AdministratorInformation Assurance Officer

Checks

Use the command "ftp" to connect the system's FTP service. Attempt to log into this host with a user name of anonymous and a password of guest (also try the password of [email protected]). If the logon is not successful, this check is Not Applicable.

Ask the SA if the system is located on a DMZ network. If the system is not located on a DMZ network, this is a finding.

Fix

Remove anonymous ftp capability or move the system to a DMZ network.
V-11940 No Change
Findings ID: GEN000100 Rule ID: SV-63095r1_rule Severity: high CCI: CCI-001230

Discussion

An operating system release is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve security issues discovered in the system software.If an extended support agreement provides security patches for the unsupported product is procured from the vendor, this finding may be downgraded to a CAT III.System Administrator

Checks

Check the version of the operating system.

Example:
# cat /etc/oracle-release

Vendor End-of-Support Information:

Oracle Linux 5 premier support ends on March 2017, but sustaining support continues indefinitely. For more information, see the Oracle Lifetime Support Policy for Oracle Linux at: http://www.oracle.com/us/support/library/elsp-lifetime-069338.pdf.

Check with the vendor for additional information.

If the version installed is not supported, this is a finding.

Fix

Upgrade to a supported version of the operating system.
V-11945 No Change
Findings ID: GEN000220 Rule ID: SV-63133r3_rule Severity: medium CCI: CCI-001069

Discussion

Changes in system libraries, binaries and other critical system files can indicate compromise or significant system events such as patching needing to be checked by automated processes and the results reviewed by the SA.

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.System Administrator

Checks

Check for the presence of an aide on the system:

# rpm –qa | grep aide

If aide is not installed, ask the SA what file integrity tool is being used to check the system.

Check the global crontabs for the presence of an "aide" job to run at least weekly, if aide is installed. Otherwise, check for the presence of a cron job to run the alternate file integrity checking application.

# grep aide /etc/cron*/*

If a tool is being run then the configuration file for the appropriate tool needs to be checked for selection lines /bin, /sbin, /lib, and /usr.

Procedure:

Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/* for the presence of an "aide" job to run at least weekly, which should have asterisks (*) in columns 3, 4, and 5.

Check the weekly cron directory (/etc/cron.weekly) for any script running "aide --check" or "aide -C" or simply "aide".

If there is not, this is a finding.

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.

Fix

Establish an automated job, scheduled to run weekly or more frequently, to run "aide --check" which is the file integrity tool to check for unauthorized system libraries or binaries.

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.
V-11946 No Change
Findings ID: GEN000340 Rule ID: SV-63277r1_rule Severity: medium CCI: CCI-000366

Discussion

Reserved UIDs are typically used by system software packages. If non-system accounts have UIDs in this range, they may conflict with system software, possibly leading to the user having permissions to modify system files.System Administrator

Checks

Check the UID assignments for all accounts.

# cut -d: -f 1,3 /etc/passwd | egrep ":[1-4][0-9]{2}$|:[0-9]{1,2}$"

Confirm all accounts with a UID of 499 and below are used by a system account. If a UID reserved for system accounts (0 - 499) is used by a non-system account, then this is a finding.

Fix

Change the UID numbers for non-system accounts with reserved UIDs (those less or equal to 499).
V-11947 No Change
Findings ID: GEN000580 Rule ID: SV-63903r3_rule Severity: medium CCI: CCI-000205

Discussion

The use of longer passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques by increasing the password search space.System Administrator

Checks

Check the system password length setting.

Procedure:
Check the password minlen option
# grep pam_cracklib.so /etc/pam.d/system-auth

Confirm the minlen option is set to at least 15 as in the example below:

password required pam_cracklib.so minlen=15

There may be other options on the line. If no such line is found, or the minlen is less than 15 this is a finding.

# grep PASS_MIN_LEN /etc/login.defs

Confirm the PASS_MIN_LEN option is set to at least 15 as in the example below:

PASS_MIN_LEN 15

If this line does not exist, or is less than 15, this is a finding.

Fix

Edit "/etc/pam.d/system-auth" to include the line:

password required pam_cracklib.so minlen=15

prior to the "password include system-auth-ac" line.

Edit /etc/login.defs to include the line:

PASS_MIN_LEN 15
V-11948 No Change
Findings ID: GEN000600 Rule ID: SV-63973r1_rule Severity: medium CCI: CCI-000192

Discussion

To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use.System Administrator

Checks

Check the ucredit setting.
# grep ucredit /etc/pam.d/system-auth
If ucredit is not set to -1, this is a finding.

Fix

Edit "/etc/pam.d/system-auth" to include the line:

password required pam_cracklib.so ucredit=-1

prior to the "password include system-auth-ac" line.
V-11972 No Change
Findings ID: GEN000620 Rule ID: SV-64071r1_rule Severity: medium CCI: CCI-000194

Discussion

To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use.System Administrator

Checks

Check the dcredit setting.

Procedure:
Check the password dcredit option
# grep pam_cracklib.so /etc/pam.d/system-auth

Confirm the dcredit option is set to -1 as in the example:

password required pam_cracklib.so dcredit=-1

There may be other options on the line. If no such line is found, or the dcredit option is not -1 this is a finding.

Fix

Edit "/etc/pam.d/system-auth" to include the line:

password required pam_cracklib.so dcredit=-1

prior to the "password include system-auth-ac" line.
V-11973 No Change
Findings ID: GEN000640 Rule ID: SV-64075r1_rule Severity: medium CCI: CCI-001619

Discussion

To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use.System Administrator

Checks

Check the ocredit setting.

Procedure:
Check the password ocredit option
# grep pam_cracklib.so /etc/pam.d/system-auth

Confirm the ocredit option is set to -1 as in the example:

password required pam_cracklib.so ocredit=-1

There may be other options on the line. If no such line is found, or the ocredit is not -1 this is a finding.

Fix

Edit "/etc/pam.d/system-auth" to include the line:

password required pam_cracklib.so ocredit=-1

prior to the "password include system-auth-ac" line.
V-11975 No Change
Findings ID: GEN000680 Rule ID: SV-64079r1_rule Severity: medium CCI: CCI-000366

Discussion

To enforce the use of complex passwords, the number of consecutive repeating characters is limited. Passwords with excessive repeated characters may be more vulnerable to password-guessing attacks.System Administrator

Checks

Check the maxrepeat setting.

Procedure:
Check the password maxrepeat configuration
# grep pam_cracklib.so /etc/pam.d/system-auth

If the maxrepeat option is missing, this is a finding.
If the maxrepeat option is set to more than 3, this is a finding.

Fix

Edit "/etc/pam.d/system-auth" to include the line:

password required pam_cracklib.so maxrepeat=3

prior to the "password include system-auth-ac" line.
V-11976 No Change
Findings ID: GEN000700 Rule ID: SV-64083r1_rule Severity: medium CCI: CCI-000180

Discussion

Limiting the lifespan of authenticators limits the period of time an unauthorized user has access to the system while using compromised credentials and reduces the period of time available for password-guessing attacks to run against a single password.System Administrator

Checks

Check the max days field (the 5th field) of /etc/shadow.
# more /etc/shadow
If the max days field is equal to 0 or greater than 60 for any user, this is a finding.

Fix

Set the max days field to 60 for all user accounts.
# passwd -x 60 <user>
V-11977 No Change
Findings ID: GEN000740 Rule ID: SV-64091r1_rule Severity: medium CCI: CCI-000199

Discussion

Limiting the lifespan of authenticators limits the period of time an unauthorized user has access to the system while using compromised credentials and reduces the period of time available for password-guessing attacks to run against a single password. Locking the password for non-interactive and automated processing accounts is preferred as it removes the possibility of accessing the account by a password. On some systems, locking the passwords of these accounts may prevent the account from functioning properly. Passwords for non-interactive/automated processing accounts must not be used for direct logon to the system.System Administrator

Checks

Ask the SA if there are any automated processing accounts on the system. If there are automated processing accounts on the system, ask the SA if the passwords for those automated accounts are changed at least once a year or are locked. If SA indicates passwords for automated processing accounts are not changed once per year or are not locked, this is a finding.

Fix

Implement or establish procedures to change the passwords of automated processing accounts at least once per year or lock them.
V-11979 No Change
Findings ID: GEN001020 Rule ID: SV-64397r1_rule Severity: medium CCI: CCI-000770

Discussion

Direct login with the root account prevents individual user accountability. Acceptable non-routine uses of the root account for direct login are limited to emergency maintenance, the use of single-user mode for maintenance, and situations where individual administrator accounts are not available.System Administrator

Checks

Check if root is used for direct logins.

Procedure:
# last root | grep -v reboot

Direct logins are indicated by the presence of a terminal or pseudo-terminal ID and/or X display name in the output of the last command. If any direct login records for root are listed, this is a finding.

Fix

Enforce policy requiring all root account access is attained by first logging into a user account and then becoming root preferably through the use of "sudo" which provides traceability to the command level. If that is not workable then using "su" to access the root account will provide traceability to the login user.
V-11980 No Change
Findings ID: GEN001060 Rule ID: SV-64435r2_rule Severity: medium CCI: CCI-000126

Discussion

If successful and unsuccessful logins and logouts are not monitored or recorded, access attempts cannot be tracked. Without this logging, it may be impossible to track unauthorized access to the system.System Administrator

Checks

Check the log files to determine if access to the root account is being logged.

Procedure:

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Examine /etc/syslog.conf or /etc/rsyslog.conf to confirm the location to which "authpriv" messages will be directed.

The default syslog.conf or rsyslog.conf uses /var/log/messages and /var/log/secure but this needs to be confirmed.

# grep @ /etc/syslog.conf

Or:

# grep @ /etc/rsyslog.conf

If a line starting with "*.*" is returned then all syslog messages will be sent to system whose address appears after the "@". In this case syslog may or may not be configured to also log "authpriv" messages locally.

# grep authpriv /etc/syslog.conf

Or:

# grep authpriv /etc/rsyslog.conf

If any lines are returned which do not start with "#" the "authpriv" messages will be sent to the indicated files or remote systems.

Try to "su -" and enter an incorrect password.

If there are no records indicating the authentication failure, this is a finding.

Fix

Troubleshoot the system logging configuration to provide for logging of root account login attempts.

Procedure:

Edit /etc/syslog.conf or /etc/rsyslog.conf to make sure "authpriv.*" messages are directed to a file or remote system.

Examine /etc/audit/audit.rules to ensure user authentication messages have not been specifically excluded.

Remove any entries that correspond to:

-a exclude,never -Fmsgtype=USER_START
-a exclude,never -Fmsgtype=USER_LOGIN
-a exclude,never -Fmsgtype=USER_AUTH
-a exclude,never -Fmsgtype=USER_END
-a exclude,never -Fmsgtype=USER_ACCT
V-11981 No Change
Findings ID: GEN001720 Rule ID: SV-63865r1_rule Severity: medium CCI: CCI-000225

Discussion

Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.System Administrator

Checks

Check global initialization files permissions:


# ls -l /etc/bashrc
# ls -l /etc/csh.cshrc
# ls -l /etc/csh.login
# ls -l /etc/csh.logout
# ls -l /etc/environment
# ls -l /etc/ksh.kshrc
# ls -l /etc/profile
# ls -l /etc/suid_profile
# ls -l /etc/profile.d/*


If global initialization files are more permissive than 0644, this is a finding.

Fix

Change the mode of the global initialization file(s) to 0644.
# chmod 0644 <global initialization file>
V-11982 No Change
Findings ID: GEN001740 Rule ID: SV-63869r1_rule Severity: medium CCI: CCI-000225

Discussion

Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.

Checks

Check the ownership of global initialization files.

Procedure:
# ls -lL etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/*
This should show information for each file. Examine to ensure the owner is always root

or:
# ls etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|xargs stat -L -c %U:%n|egrep -v "^root"

This will show you only the owner and filename of files not owned by root.

If any global initialization file is not owned by root, this is a finding.

Fix

Change the ownership of global initialization files with incorrect ownership.

Procedure:
# chown root <global initialization files>

or:
# ls etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|xargs stat -L -c %U:%n|egrep -v "^root"|cut -d: -f2|xargs chown root
will set the owner of all files not currently owned by root to root.
V-11983 No Change
Findings ID: GEN001760 Rule ID: SV-63871r1_rule Severity: medium CCI: CCI-000225

Discussion

Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Check the group ownership of global initialization files.

Procedure:
# ls -lL etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/*

This should show information for each file. Examine to ensure the group is always root

or:
# ls -lL etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|sed "s/^[^\/]*//"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):"
will show you only the group and filename of files not owned by one of the approved groups.

If any global initialization file is not group-owned by root, sys, bin, other, system, or the system default, this is a finding.

Fix

Change the group ownership of the global initialization file(s) with incorrect group ownership.

Procedure:
# chgrp root <global initialization file>
or:
# ls -lL /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|sed "s/^[^\/]*//"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):"|cut -d: -f2|xargs chgrp root
will set the group of all files not currently owned by an approved group to root.
V-11984 No Change
Findings ID: GEN001820 Rule ID: SV-63307r1_rule Severity: medium CCI: CCI-000225

Discussion

If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.System Administrator

Checks

Check skeleton files ownership.
# ls -alL /etc/skel
If a skeleton file is not owned by root or bin, this is a finding.

Fix

Change the ownership of skeleton files with incorrect mode:
# chown root <skeleton file>
or
# ls -L /etc/skel|xargs stat -L -c %U:%n|egrep -v "^(root|bin):"|cut -d: -f2|chown root
will change all files not owned by root or bin to root.
V-11985 No Change
Findings ID: GEN001840 Rule ID: SV-63327r3_rule Severity: medium CCI: CCI-000366

Discussion

The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Check the global initialization files' executable search paths.

Procedure:
# grep PATH /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/*

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the global initialization file(s) with PATH variables containing relative paths and remove any relative path from the PATH variables that have not been authorized by the ISSO.

Remove any empty path entries that are defined in these files.
V-11986 No Change
Findings ID: GEN001900 Rule ID: SV-63541r3_rule Severity: medium CCI: CCI-000366

Discussion

The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories, such as a leading or trailing colon, two consecutive colons, or a single period; this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Verify local initialization files have executable search path containing only absolute paths or relative paths are necessary and documented with the ISSO.

Procedure:

NOTE: This must be done in the BASH shell.

# cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep -l PATH {} \;

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the local initialization file and remove the relative path entry from the executable search path variable. If this is not feasible, justify and document the necessity of having the relative path for a specific application with the ISSO.

Remove any empty path entries that are defined in these files.
V-11987 No Change
Findings ID: GEN001980 Rule ID: SV-63581r1_rule Severity: medium CCI: CCI-000366

Discussion

A plus (+) in system accounts files causes the system to lookup the specified entry using NIS. If the system is not using NIS, no such entries should exist.System Administrator

Checks

Check system configuration files for plus (+) entries.

Procedure:
# find / -name .rhosts
# grep + /<directorylocation>/.rhosts

# find / -name .shosts
# grep + /<directorylocation>/.shosts

# find / -name hosts.equiv
# grep + /<directorylocation>/hosts.equiv

# find / -name shosts.equiv
# grep + /<directorylocation>/shosts.equiv

# grep + /etc/passwd
# grep + /etc/shadow
# grep + /etc/group

If the .rhosts, .shosts, hosts.equiv, shosts.equiv, /etc/passwd, /etc/shadow, and/or /etc/group files contain a plus (+) and do not define entries for NIS+ netgroups, this is a finding.

Fix

Edit the .rhosts, .shosts, hosts.equiv, shosts.equiv, /etc/passwd, /etc/shadow, and/or /etc/group files and remove entries containing a plus (+).
V-11988 No Change
Findings ID: GEN002040 Rule ID: SV-63621r1_rule Severity: high CCI: CCI-000366

Discussion

The .rhosts, .shosts, hosts.equiv, and shosts.equiv files are used to configure host-based authentication for individual users or the system. Host-based authentication is not sufficient for preventing unauthorized access to the system.System AdministratorInformation Assurance Officer

Checks

Check for the existence of the files.

# find / -name .rhosts
# find / -name .shosts
# find / -name hosts.equiv
# find / -name shosts.equiv

If .rhosts, .shosts, hosts.equiv, or shosts.equiv are found and their use has not been documented and approved by the IAO, this is a finding.

Fix

Remove all the r-commands access control files.

Procedure:
# find / -name .rhosts -exec rm {} \;
# find / -name .shosts -exec rm {} \;
# find / -name hosts.equiv -exec rm {} \;
# find / -name shosts.equiv -exec rm {} \;
V-11989 No Change
Findings ID: GEN002100 Rule ID: SV-63647r1_rule Severity: medium CCI: CCI-000366

Discussion

.rhosts files are used to specify a list of hosts permitted remote access to a particular account without authenticating. The use of such a mechanism defeats strong identification and authentication requirements.System AdministratorInformation Assurance Officer

Checks

Check the PAM configuration for rhosts_auth.

Example:
# grep rhosts_auth /etc/pam.d/*

If a rhosts_auth entry is found, this is a finding.

Fix

Edit the file(s) in /etc/pam.d referencing the rhosts_auth module, and remove the references to the rhosts_auth module.
V-11990 No Change
Findings ID: GEN002540 Rule ID: SV-63797r1_rule Severity: medium CCI: CCI-000225

Discussion

If a public directory has the sticky bit set and is not group-owned by a privileged GID, unauthorized users may be able to modify files created by others.

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, (e.g., /tmp), and for directories requiring global read/write access.System Administrator

Checks

Check the group-ownership of public directories.

Procedure:
# find / -type d -perm -1002 -exec ls -ld {} \;

If any public directory is not group-owned by root, sys, bin, or an application group, this is a finding.

Fix

Change the group-ownership of the public directory.

Procedure:
# chgrp root /tmp

(Replace root with a different system group and/or /tmp with a different public directory as necessary.)
V-11994 No Change
Findings ID: GEN003040 Rule ID: SV-64401r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.System Administrator

Checks

List all crontabs on the system.

# ls -lL /var/spool/cron

# ls -lL /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -lL /etc/cron*|grep -v deny

If any crontab is not owned by root or the creating user, this is a finding.

Fix

Change the crontab owner to root or the crontab creator.

# chown root <crontab file>
or
# chown <user> <crontab file>
V-11995 No Change
Findings ID: GEN003060 Rule ID: SV-64395r1_rule Severity: medium CCI: CCI-000225

Discussion

To centralize the management of privileged account crontabs, of the default system accounts, only root may have a crontab.System Administrator

Checks

Check the cron.allow and cron.deny files for the system.

# more /etc/cron.allow
# more /etc/cron.deny

If a default system account (such as bin, sys, adm, or others, traditionally UID less than 500) is listed in the cron.allow file, or not listed in the cron.deny file and if no cron.allow file exists, this is a finding.

Fix

Remove default system accounts (such as bin, sys, adm, or others, traditionally UID less than 500) from the cron.allow file if it exists, or add those accounts to the cron.deny file.
V-11996 No Change
Findings ID: GEN003500 Rule ID: SV-64311r2_rule Severity: low CCI: CCI-000366

Discussion

Process core dumps contain the memory in use by the process when it crashed. Process core dump files can be of significant size and their use can result in file systems filling to capacity, which may result in Denial of Service. Process core dumps can be useful for software debugging. System Administrator

Checks

# ulimit -Hc
If the above command does not return 0 and the enabling of core dumps has not been documented and approved by the ISSO, this a finding.

Fix

Edit /etc/security/limits.conf and set a hard limit for "core" to 0 for all users. A new logon will be required for the changes to take effect.
V-11997 No Change
Findings ID: GEN003520 Rule ID: SV-64427r2_rule Severity: low CCI: CCI-000225

Discussion

Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the kernel core dump data directory is not owned by root, the core dumps contained in the directory may be subject to unauthorized access.System Administrator

Checks

Verify the location of the kernel core dump data directory:
# grep “path” /etc/kdump.conf

Note: If this setting is not configured or commented out, the default kernel dump data directory is /var/crash.

Check the ownership of the dump data directory:
# ls –ld <path to kernel core dump data directory>

If the kernel core dump data directory is not owned by root, this is a finding.

Fix

Change the owner of the kernel core dump data directory to root.
# chown root <path to kernel core dump data directory>
V-11999 No Change
Findings ID: GEN003540 Rule ID: SV-64439r1_rule Severity: medium CCI: CCI-000366

Discussion

A common type of exploit is the stack buffer overflow. An application receives, from an attacker, more data than it is prepared for and stores this information on its stack, writing beyond the space reserved for it. This can be designed to cause execution of the data written on the stack. One mechanism to mitigate this vulnerability is for the system to not allow the execution of instructions in sections of memory identified as part of the stack.System Administrator

Checks

If the system being evaluated is running a Red Hat compatible operating system kernel, check that the "kernel.exec-shield" kernel parameter is set to "1" in /etc/sysctl.conf. If the system is running an Oracle Unbreakable Enterprise kernel, verify that Oracle's Data Execution Prevention is enabled.

First, determine if the system is operating an Oracle Unbreakable Enterprise Kernel (UEK):

# uname -r | grep uek

If no value is returned, the system is running a Red Hat compatible kernel. Verify the "kernel.exec-shield" kernel parameter is set to "1" in /etc/sysctl.conf:

# grep ^kernel\.exec-shield /etc/sysctl.conf | awk -F= '{ print $2 }'
kernel.exec-shield = 1

If there is no value returned or if a value is returned that is not "2", this is a finding.

If the system was found to be running an Unbreakable Enterprise Kernel, verify DEP is enabled:

# dmesg | grep 'NX.*protection:

If there is no value returned or if a value is returned that is not "NX (Execute Disable) protection: active", this is a finding.

Note that this is not a finding when the underlying processor architecture does not support the "Execute Disable" (NX) capability. To determine if the processor supports this capability, run the command:

# cat /proc/cpuinfo | grep flags | xargs -n 1 echo | grep -w "nx" | sort -u

If a system's underlying processor supports this functionality, a single entry containing the keyword "nx" will be returned.

Fix

If the system being evaluated is running a Red Hat compatible operating system kernel, then ensure that the "kernel.exec-shield" kernel parameter is set to "1". If the system is running an Oracle Unbreakable Enterprise Kernel, this parameter does not exist. When an Unbreakable Enterprise Kernel is booted, Oracle's Data Execution Prevention (DEP) feature will leverage the hardware-enforced NX (never execute) bit of compatible CPUs to protect against code being executed from the stack. By default, DEP is enabled. If DEP is not enabled, ensure the string "noexec=off" does not appear in /boot/grub/grub.conf.

First, determine if the system is operating an Oracle Unbreakable Enterprise Kernel (UEK):

# uname -r | grep uek

If no value is returned, the system is running a Red Hat compatible kernel. Edit (or add if necessary) the entry in /etc/sysctl.conf for the "kernel.exec-shield" kernel parameter. Ensure this parameter is set to "1" as in:

kernel.exec-shield = 1

If this was not already the default, reboot the system for the change to take effect.

If the system was found to be running an Unbreakable Enterprise Kernel, then ensure the string "noexec=off" is not found in /boot/grub/grub.conf:

# grep noexec=off /boot/grub/grub.conf

If found, remove the offending entry and reboot the system for the change to take effect.
V-12002 No Change
Findings ID: GEN003600 Rule ID: SV-64451r1_rule Severity: medium CCI: CCI-001551

Discussion

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.System Administrator

Checks

Verify the system does not accept source-routed IPv4 packets.

Procedure:
# grep [01] /proc/sys/net/ipv4/conf/*/accept_source_route|egrep "default|all"

If all of the returned lines do not end with 0, this is a finding.

Note: The same setting is used by Linux for both the local acceptance and forwarding of source-routed IPv4 packets.

Fix

Configure the system to not accept source-routed IPv4 packets.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_source_route=0" and "net.ipv4.conf.default.accept_source_route=0".

Reload the sysctls.
Procedure:
# sysctl -p
V-12003 No Change
Findings ID: GEN003620 Rule ID: SV-64215r1_rule Severity: low CCI: CCI-001208

Discussion

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.trueSystem Administrator

Checks

Determine if the /home path is a separate filesystem.
# grep "/home " /etc/fstab
If no result is returned, /home is not on a separate filesystem this is a finding.

Fix

Migrate the /home (or equivalent) path onto a separate file system.
V-12004 No Change
Findings ID: GEN003660 Rule ID: SV-64229r2_rule Severity: medium CCI: CCI-000126

Discussion

Monitoring and recording successful and unsuccessful logins assists in tracking unauthorized access to the system.System Administrator

Checks

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Check /etc/syslog.conf or /etc/rsyslog.conf and verify the authpriv facility is logging both the "notice" and "info" priority messages.

Procedure:

For a given action all messages of a higher severity or "priority" are logged. The three lowest priorities in ascending order are "debug", "info" and "notice". A priority of "info" will include "notice". A priority of "debug" includes both "info" and "notice".

Enter/Input for syslog:

# grep "authpriv.debug" /etc/syslog.conf
# grep "authpriv.info" /etc/syslog.conf
# grep "authpriv\.\*" /etc/syslog.conf

Enter/Input for rsyslog:

# grep "authpriv.debug" /etc/rsyslog.conf
# grep "authpriv.info" /etc/rsyslog.conf
# grep "authpriv\.\*" /etc/rsyslog.conf

If an "authpriv.*", "authpriv.debug", or "authpriv.info" entry is not found, this is a finding.

Fix

Edit /etc/syslog.conf or /etc/rsyslog.conf and add local log destinations for "authpriv.*", "authpriv.debug" or "authpriv.info".
V-12005 No Change
Findings ID: GEN003700 Rule ID: SV-64231r1_rule Severity: medium CCI: CCI-000305

Discussion

Unnecessary services should be disabled to decrease the attack surface of the system.System Administrator

Checks

# ps -ef |grep xinetd
If xinetd is not running, this check is not a finding.
# grep -v "^#" /etc/xinetd.conf
# grep disable /etc/xinetd.d/* |grep no
If no active services are found, and the inetd daemon is running, this is a finding.

Fix

# service xinetd stop ; chkconfig xinetd off
V-12006 No Change
Findings ID: GEN004540 Rule ID: SV-63759r2_rule Severity: medium CCI: CCI-000366

Discussion

The HELP command should be disabled to mask version information. The version of the SMTP service software could be used by attackers to target vulnerabilities present in specific software versions.System Administrator

Checks

Check if Help is disabled. This rule is for "sendmail" only and not applicable to "Postfix".

Procedure:
# telnet localhost 25
> help

If the help command returns any sendmail version information, this is a finding. If sendmail is not installed, this check is not applicable.

Fix

To disable the SMTP HELP command, clear the Sendmail help file.
# echo > /etc/mail/helpfile
V-12010 No Change
Findings ID: GEN004800 Rule ID: SV-62885r1_rule Severity: medium CCI: CCI-000366

Discussion

FTP is typically unencrypted and presents confidentiality and integrity risks. FTP may be protected by encryption in certain cases, such as when used in a Kerberos environment. SFTP and FTPS are encrypted alternatives to FTP.trueSystem Administrator

Checks

Perform the following to determine if unencrypted FTP is enabled:

# chkconfig --list gssftp
# chkconfig --list vsftpd

If any of these services are found, ask the SA if these services are encrypted. If they are not, this is a finding.

Fix

Disable the FTP daemons.

Procedure:
# chkconfig gssftp off
# chkconfig vsftpd off
V-12011 No Change
Findings ID: GEN005040 Rule ID: SV-63113r1_rule Severity: medium CCI: CCI-000225

Discussion

The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask is stored as a 4-digit number, the first digit representing special access modes is typically ignored or required to be zero (0).System Administrator

Checks

Check the umask setting for FTP users.

Procedure:
For gssftp:
Assuming an anonymous ftp user has been defined with no user initialization script invoked to change the umask

# ftp localhost
Name: (localhost:root): anonymous
Password: anything
ftp>umask

If the umask value returned is not 077, this is a finding.
or:
# grep "server_args" /etc/xinetd.d/gssftp

The default umask for FTP is "023" if the server _args entry does not contain "-u 077" this is a finding.

For vsftp:
# grep "_mask" /etc/vsftpd/vsftpd.conf
The default "local_umask" setting is 077. If this has been changed, or the "anon_umask" setting is not 077, this is a finding.

Fix

Edit the initialization files for the ftp user and set the umask to 077.

Procedure:

For gssftp:
Modify the /etc/xinetd.d/gssftp file adding "-u 077" to the server_args entry.

For vsftp:
Modify the "/etc/vsftpd/vsftpd.conf" setting "local_umask" and "anon_umask" to 077.
V-12014 No Change
Findings ID: GEN005180 Rule ID: SV-63205r1_rule Severity: medium CCI: CCI-000225

Discussion

.Xauthority files ensure the user is authorized to access specific X Windows host. Excessive permissions may permit unauthorized modification of these files, which could lead to Denial of Service to authorized access or allow unauthorized access to be obtained.System Administrator

Checks

Check the file permissions for the .Xauthority files.

Procedure:
# ls -la |egrep "(\.Xauthority|\.xauth)"

If the file mode is more permissive than 0600, this is finding.

Fix

Change the mode of the .Xauthority files.

Procedure:
# chmod 0600 .Xauthority
V-12016 No Change
Findings ID: GEN005220 Rule ID: SV-63313r1_rule Severity: medium CCI: CCI-000297

Discussion

If access to the X server is not restricted, a user's X session may be compromised.System Administrator

Checks

Determine if the X server is running.
Procedure:
# ps -ef |grep X

Determine if xauth is being used.
Procedure:
# xauth
xauth> list

If the above command sequence does not show any host other than the localhost, then xauth is not being used.

Search the system for an X*.hosts file, where "*" is a display number used to limit X window connections. If no files are found, X*.hosts files are not being used. If the X*.hosts files contain any unauthorized hosts, this is a finding.

If both xauth and X*.hosts files are not being used, this is a finding.

Fix

Create an X*.hosts file, where "*" is a display number used to limit X window connections. Add the list of authorized X clients to the file.
V-12017 No Change
Findings ID: GEN005240 Rule ID: SV-63329r1_rule Severity: medium CCI: CCI-000225

Discussion

If unauthorized clients are permitted access to the X server, a user's X session may be compromised.System Administrator

Checks

Check the X window system access is limited to authorized clients.

Procedure:
# xauth
xauth> list

Ask the SA if the clients listed are authorized. If any are not, this is a finding.

Fix

Remove unauthorized clients from the xauth configuration.
# xauth remove <display name>
V-12018 No Change
Findings ID: GEN005260 Rule ID: SV-63347r1_rule Severity: medium CCI: CCI-001436

Discussion

If unauthorized clients are permitted access to the X server, a user's X session may be compromised.System Administrator

Checks

Determine if the X window system is running.

Procedure:
# ps -ef |grep Xorg

Ask the SA if the X window system is an operational requirement. If it is not, this is a finding.

Fix

Disable the X Windows server on the system.
V-12019 No Change
Findings ID: GEN005360 Rule ID: SV-63443r1_rule Severity: medium CCI: CCI-000225

Discussion

The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. If the file is not owned by root, it may be subject to access and modification from unauthorized users.System AdministratorECLP-1

Checks

Determine the owner of the SNMP configuration file.

Procedure:
Find the snmpd.conf file. The default install location is /etc/snmp/snmpd.conf but may be different depending on the SNMP agent installed.

# find / -name snmpd.conf
# ls -lL <snmpd.conf>

If the snmpd.conf file is not owned by root, this is a finding.

Fix

Change the owner of the snmpd.conf file to root.

Procedure:
# chown root <snmpd.conf file>
V-12020 No Change
Findings ID: GEN005440 Rule ID: SV-63495r1_rule Severity: medium CCI: CCI-000366

Discussion

Syslog messages are typically unencrypted, may contain sensitive information, and are restricted to the enclave.System Administrator

Checks

Ask the SA if the loghost server is collecting data for hosts outside the local enclave. If it is, this is a finding.

Fix

Configure the hosts outside of the local enclave to not log to this system.
V-12021 No Change
Findings ID: GEN005480 Rule ID: SV-63531r1_rule Severity: medium CCI: CCI-000366

Discussion

Unintentionally running a syslog server accepting remote messages puts the system at increased risk. Malicious syslog messages sent to the server could exploit vulnerabilities in the server software itself, could introduce misleading information in to the system's logs, or could fill the system's storage leading to a Denial of Service.System Administrator

Checks

Ask the SA if the system is an authorized syslog server. If the system is an authorized syslog server, this is not applicable.

Determine if the system's syslog service is configured to accept remote messages.

# ps -ef | grep syslogd

If the '-r' option is present, the system is configured to accept remote syslog messages, and this is a finding.

Fix

Edit /etc/sysconfig/syslog to removing the '-r' in SYSLOGD_OPTIONS. Restart the syslogd service.
V-12022 No Change
Findings ID: GEN005540 Rule ID: SV-64101r1_rule Severity: medium CCI: CCI-000366

Discussion

The SSH daemon must be configured for IP filtering to provide a layered defense against connection attempts from unauthorized addresses.System Administrator

Checks

Check the TCP wrappers configuration files to determine if sshd is configured to use TCP wrappers.

Procedure:
# grep sshd /etc/hosts.deny
# grep sshd /etc/hosts.allow

If no entries are returned, the TCP wrappers are not configured for sshd, this is a finding.

Fix

Add appropriate IP restrictions for SSH to the /etc/hosts.deny and/or /etc/hosts.allow files.
V-12023 No Change
Findings ID: GEN005600 Rule ID: SV-64113r1_rule Severity: medium CCI: CCI-000366

Discussion

If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices.System Administrator

Checks

Check if the system is configured for IPv4 forwarding. If the system is a VM host and acts as a router solely for the benefits of its client systems, then this rule is not applicable.

Procedure:
# cat /proc/sys/net/ipv4/ip_forward

If the value is set to "1", IPv4 forwarding is enabled this is a finding.

Fix

Edit "/etc/sysctl.conf" and set net.ipv4.ip_forward to "0".

Restart the system or run "sysctl -p" to make the change take effect.
V-12024 No Change
Findings ID: GEN006000 Rule ID: SV-64137r1_rule Severity: medium CCI: CCI-000366

Discussion

Public (IM) systems are not approved for use and may result in the unauthorized distribution of information. IM clients provide a way for a user to send a message to one or more other users in real time. Additional capabilities may include file transfer and support for distributed game playing. Communication between clients and associated directory services are managed through messaging servers. Commercial IM clients include AOL Instant Messenger (AIM), MSN Messenger, and Yahoo! Messenger.

IM clients present a security issue when the clients route messages through public servers. The obvious implication is potentially sensitive information could be intercepted or altered in the course of transmission. This same issue is associated with the use of public e-mail servers. In order to reduce the potential for disclosure of sensitive Government information and to ensure the validity of official government information, IM clients connecting to public IM services will not be installed. Clients use to access internal or DoD-controlled IM services are permitted.System Administrator

Checks

If an IM client is installed, ask the SA if it has access to any public domain IM servers. If it does have access to public servers, this is a finding.

Fix

Uninstall the IM client from the system, or configure the client to only connect to DoD-approved IM services.
V-12025 No Change
Findings ID: GEN006040 Rule ID: SV-64127r1_rule Severity: medium CCI: CCI-001436

Discussion

Peer-to-peer file-sharing software can result in the unintentional exfiltration of information. There are also many legal issues associated with these types of utilities including copyright infringement or other intellectual property issues. The ASD Memo "Use of Peer-to-Peer (P2P) File-Sharing Applications across the DoD" states the following:

“P2P file-sharing applications are authorized for use on DOD networks with approval by the appropriate Designated Approval Authority (DAA). Documented requirements, security architecture, configuration management process, and a training program for users are all requirements within the approval process. The unauthorized use of application or services, including P2P applications, is prohibited, and such applications or services must be eliminated.”

P2P applications include, but are not limited to, the following:

-Napster
-Kazaa
-ARES
-Limewire
-IRC Chat Relay
-BitTorrentSystem AdministratorDesignated Approving Authority

Checks

Ask the SA if any peer-to-peer file-sharing applications are installed. Some examples of these applications include:

- Napster
- Kazaa
- ARES
- Limewire
- IRC Chat Relay
- BitTorrent

If any of these applications are installed, this is a finding.

Fix

Uninstall the peer-to-peer file sharing application(s) from the system.
V-12026 No Change
Findings ID: GEN006420 Rule ID: SV-63785r1_rule Severity: medium CCI: CCI-000366

Discussion

The use of hard-to-guess NIS domain names provides additional protection from unauthorized access to the NIS directory information.System Administrator

Checks

Check the domain name for NIS maps.

Procedure:
# domainname

If the name returned is simple to guess, such as the organization name, building or room name, etc., this is a finding.

If the system does not use NIS, this is not applicable.

Fix

Change the NIS domainname to a value difficult to guess. Consult vendor documentation for the required procedure.
V-12028 No Change
Findings ID: GEN006560 Rule ID: SV-63761r1_rule Severity: medium CCI: CCI-000366

Discussion

Timely notifications of potential security compromises minimize the potential damage.

Minimally, the system must log these events and the SA and the IAO will receive the notifications during the daily system log review. If feasible, active alerting (such as e-mail or paging) should be employed consistent with the site's established operations management systems and procedures.System AdministratorInformation Assurance Officer

Checks

For each security tool on the system, determine if the tool is configured to notify the IAO and SA of any detected security problem. If such notifications are not configured, this is a finding.

Fix

Configure the security tools on the system to notify the IAO and SA when any security issues are detected.
V-12030 No Change
Findings ID: GEN006620 Rule ID: SV-63551r1_rule Severity: medium CCI: CCI-000366

Discussion

If the system's access control program is not configured with appropriate rules for allowing and denying access to system network resources, services may be accessible to unauthorized hosts.System Administrator

Checks

Check for the existence of the "/etc/hosts.allow" and "/etc/hosts.deny" files.

Procedure:
# ls -la /etc/hosts.allow
# ls -la /etc/hosts.deny

If either file does not exist, this is a finding.

Check for the presence of a "default deny" entry.

Procedure:
# grep "ALL: ALL" /etc/hosts.deny

If the "ALL: ALL" entry is not present the "/etc/hosts.deny" file, any TCP service from a host or network not matching other rules will be allowed access. If the entry is not in "/etc/hosts.deny", this is a finding.

Fix

Edit the "/etc/hosts.allow" and "/etc/hosts.deny" files to configure access restrictions.
V-12038 No Change
Findings ID: GEN000000-LNX00620 Rule ID: SV-63013r1_rule Severity: medium CCI: CCI-000225

Discussion

The securetty file contains the list of terminals permitting direct root logins. It must be protected from unauthorized modification.System Administrator

Checks

Check /etc/securetty group ownership:

# ls -lL /etc/securetty

If /etc/securetty is not group owned by root, sys, or bin, then this is a finding.

Fix

Change the group-owner of /etc/securetty to root, sys, or bin.
Example:
# chgrp root /etc/securetty
V-12039 No Change
Findings ID: GEN000000-LNX00640 Rule ID: SV-63061r1_rule Severity: medium CCI: CCI-000225

Discussion

The securetty file contains the list of terminals permitting direct root logins. It must be protected from unauthorized modification.System Administrator

Checks

Check /etc/securetty ownership.

Procedure:
# ls -lL /etc/securetty

If /etc/securetty is not owned by root, this is a finding.

Fix

Change the owner of the /etc/securetty file to root.

Procedure:
# chown root /etc/securetty
V-12040 No Change
Findings ID: GEN000000-LNX00660 Rule ID: SV-63071r1_rule Severity: medium CCI: CCI-000225

Discussion

The securetty file contains the list of terminals permitting direct root logins. It must be protected from unauthorized modification.System Administrator

Checks

Check /etc/securetty permissions.

Procedure:
# ls -lL /etc/securetty

If /etc/securetty has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the /etc/securetty file to 0600.

Procedure:
# chmod 0600 /etc/securetty
V-12049 No Change
Findings ID: GEN003865 Rule ID: SV-64029r2_rule Severity: medium CCI: CCI-000305

Discussion

Network analysis tools allow for the capture of network traffic visible to the system.

If the system is being used as a network analysis/troubleshooting system then these tools are allowed if documented.System Administrator

Checks

Determine if any network analysis tools are installed.

Procedure:

# find / -name ethereal
# find / -name wireshark
# find / -name tshark
# find / -name nc
# find / -name tcpdump
# find / -name snoop

If any network analysis tools are found, this is a finding.

Fix

Remove each network analysis tool binary from the system. Remove package items with a package manager, others remove the binary directly.

Procedure:
Find the binary file:

# find / -name <Item to be removed>

Find the package, if any, to which it belongs:

# rpm -qf <binary file>

Remove the package if it does not also include other software:

# rpm -e <package name>

or

# yum remove <package name>

If the item to be removed is not in a package, or the entire package cannot be removed because of other software it provides, remove the item's binary file.

# rm <binary file>
V-22290 No Change
Findings ID: GEN000241 Rule ID: SV-63143r4_rule Severity: medium CCI: CCI-000366

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. Internal system clocks tend to drift and require periodic resynchronization to ensure their accuracy. Software, such as ntpd, can be used to continuously synchronize the system clock with authoritative sources. Alternatively, the system may be synchronized periodically, with a maximum of one day between synchronizations.

If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.System Administrator

Checks

Check to see if ntp is running in continuous mode.

# ps -ax | grep ntp

If the process is found, then check the ntp.conf file for the maxpoll option setting.

# grep maxpoll /etc/ntp.conf

If the option is set to 17 or is not set, this is a finding.

Fix

Enable the NTP daemon for continuous synchronization.

# service ntpd start ; chkconfig ntpd on

Edit the "/etc/ntp.conf" file and add or update an entry to define "maxpoll" to "10".
V-22291 No Change
Findings ID: GEN000242 Rule ID: SV-63147r1_rule Severity: medium CCI: CCI-000160

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. For redundancy, two time sources are required so synchronization continues to function if one source fails.

If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.

Note: For the network time protocol (NTP), the requirement is two servers, but it is recommended to configure at least four distinct time servers which allow NTP to effectively exclude a time source not consistent with the others. The system's local clock must be excluded from the count of time sources.System Administrator

Checks

Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/*, or scripts in the /etc/cron.daily directory for the presence of an "ntpd -qg" job. If the "ntpd -qg" command is not invoked with at least two external NTP servers listed, this is a finding.

Check the NTP daemon configuration for at least two external servers.
# grep ^server /etc/ntp.conf | egrep -v '(127.127.1.0|127.127.1.1)'
If less than two servers or external reference clocks (127.127.x.x other than 127.127.1.0 or 127.127.1.1) are listed, this is a finding.

Fix

If using "ntpd -qg", add additional NTP servers to the cron job running "ntpd -qg".

If using the NTP daemon, add an additional "server" line to /etc/ntp.conf for each additional NTP server.
V-22292 No Change
Findings ID: GEN000244 Rule ID: SV-63153r1_rule Severity: low CCI: CCI-000160

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. The network architecture should provide multiple time servers within an enclave providing local service to the enclave and synchronize with time sources outside of the enclave.

If this server is an enclave time server, this requirement is not applicable.

If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.System Administrator

Checks

Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/*, or scripts in the /etc/cron.daily directory for the presence of an "ntpd -qg" job. If the "ntpd -qg" command is invoked with NTP servers outside of the enclave, this is a finding.

Check the NTP daemon configuration for NTP servers.
# grep ^server /etc/ntp.conf | grep -v 127.127.1.1
If an NTP server is listed outside of the enclave, this is a finding.

Fix

If using "ntpd -qg", remove NTP servers external to the enclave from the cron job running "ntpd -qg".

If using the NTP daemon, remove the "server" line from /etc/ntp.conf for each NTP server external to the enclave.
V-22294 No Change
Findings ID: GEN000250 Rule ID: SV-63161r1_rule Severity: medium CCI: CCI-000225

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not owned by a system account, unauthorized modifications could result in the failure of time synchronization.System Administrator

Checks

Check the ownership of the NTP configuration file.
# ls -l /etc/ntp.conf
If the owner is not root, this is a finding.

Fix

Change the owner of the NTP configuration file.
# chown root /etc/ntp.conf
V-22295 No Change
Findings ID: GEN000251 Rule ID: SV-63165r1_rule Severity: medium CCI: CCI-000225

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not owned by a system group, unauthorized modifications could result in the failure of time synchronization.System Administrator

Checks

Check the group ownership of the NTP configuration file.

Procedure:
# ls -lL /etc/ntp.conf

If the group owner is not root, bin, or sys, this is a finding.

Fix

Change the group-owner of the NTP configuration file.

Procedure:
# chgrp root /etc/ntp.conf
V-22296 No Change
Findings ID: GEN000252 Rule ID: SV-63171r1_rule Severity: medium CCI: CCI-000225

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not protected, unauthorized modifications could result in the failure of time synchronization.System Administrator

Checks

Check the mode for the NTP configuration file is not more permissive than 0640.
# ls -l /etc/ntp.conf

If the mode is more permissive than 0640, this is a finding.

Fix

Change the mode of the NTP configuration file to 0640 or more restrictive.
# chmod 0640 /etc/ntp.conf
V-22297 No Change
Findings ID: GEN000253 Rule ID: SV-63177r1_rule Severity: medium CCI: CCI-000225

Discussion

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not protected, unauthorized modifications could result in the failure of time synchronization.System Administrator

Checks

Check the NTP configuration file has no extended ACL.
# ls -l /etc/ntp.conf
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the NTP configuration file.
# setfacl --remove-all /etc/ntp.conf
V-22298 No Change
Findings ID: GEN000450 Rule ID: SV-63367r1_rule Severity: low CCI: CCI-000054

Discussion

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.

If the defined value of 10 logins does not meet operational requirements, the site may define the permitted number of simultaneous login sessions based on operational requirements.

This limit is for the number of simultaneous login sessions for EACH user account. This is NOT a limit on the total number of simultaneous login sessions on the system.trueSystem Administrator

Checks

Check for a default maxlogins line in the /etc/security/limits.conf and /etc/security/limits.d/* files.

Procedure:
#grep maxlogins /etc/security/limits.conf /etc/security/limits.d/*

The default maxlimits should be set to a max of 10 or a documented site defined number:

* - maxlogins 10

If no such line exists, this is a finding.

Fix

Add a "maxlogins" line such as "* hard maxlogins 10" to /etc/security/limits.conf or a file in /etc/security/limits.d.

The enforced maximum should be defined by site requirements and policy.
V-22299 No Change
Findings ID: GEN000452 Rule ID: SV-63373r1_rule Severity: low CCI: CCI-000052

Discussion

Providing users with feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.System Administrator

Checks

Check that pam_lastlog is used and not silent, or that the SSH daemon is configured to display last login information.

# grep pam_lastlog /etc/pam.d/sshd
If pam_lastlog is present, and does not have the "silent" option, this is not a finding.

# grep -i PrintLastLog /etc/ssh/sshd_config

If PrintLastLog is not present in the configuration, this is not a finding. This is the default setting.
If PrintLastLog is present in the configuration and set to "yes" (case insensitive), this is not a finding.
Otherwise, this is a finding.

Fix

Implement pam_lastlog, or enable PrintLastLog in the SSH daemon.

To enable pam_lastlog, add a line such as "session required pam_lastlog.so" to /etc/pam.d/sshd.

To enable PrintLastLog in the SSH daemon, remove any lines disabling this option from /etc/ssh/sshd_config.
V-22301 No Change
Findings ID: GEN000510 Rule ID: SV-63633r1_rule Severity: low CCI: CCI-000061

Discussion

To protect the on-screen content of a session, it must be replaced with a publicly-viewable pattern upon session lock. Examples of publicly viewable patterns include screen saver patterns, photographic images, solid colors, or a blank screen, so long as none of those patterns convey sensitive information.

This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices, as well as, to graphical desktop environments provided to remote systems using remote access protocols.System Administrator

Checks

Determine if a publicly-viewable pattern is displayed during a session lock. Some screensaver themes available but not included in the operating system distribution use a snapshot of the current screen as a graphic. This theme does not qualify as a publicly-viewable pattern. If the screen lock pattern is not publicly-viewable, this is a finding.

Fix

Configure the system to display a publicly-viewable pattern during a session lock. This is done graphically by selecting a screensaver theme using gnome-screensaver-preferences command. Any of the themes distributed with this operating system may be used including "Blank Screen".
V-22302 No Change
Findings ID: GEN000585 Rule ID: SV-63933r2_rule Severity: medium CCI: CCI-000205

Discussion

Some common password hashing schemes only process the first eight characters of a user's password, which reduces the effective strength of the password.System Administrator

Checks

Verify no valid password hash in /etc/passwd or /etc/shadow begins with a character other than an underscore (_) or dollar sign ($).

# cut -d ':' -f2 /etc/passwd
# cut -d ':' -f2 /etc/shadow

If any valid password hash is present that does not have an initial underscore (_) or dollar sign ($) character, this is a finding.

Note: Locked accounts are indicated by a leading exclamation point (!). System accounts, other than "root", may have an asterisk (*) in the password field. On systems utilizing shadow passwords, the password field in /etc/passwd will be a single "x".

Fix

Change the passwords for all accounts using non-compliant password hashes.

(This requires GEN000590 is already met.)
V-22303 No Change
Findings ID: GEN000590 Rule ID: SV-63943r2_rule Severity: medium CCI: CCI-000803

Discussion

Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes more vulnerable to compromise.System Administrator

Checks

Verify the algorithm used for password hashing is of the SHA-2 family.
# egrep "password .* pam_unix.so" /etc/pam.d/system-auth-ac

# egrep "ENCRYPT_METHOD" /etc/login.defs

# egrep "crypt_style" /etc/libuser.conf

If any output indicates the hash algorithm is not set to sha256 or sha512, this is a finding.

Fix

Change the default password algorithm.
# authconfig --passalgo=sha512 --update

NOTE: Executing the above command will also update the required parameters in /etc/login.defs and /etc/libuser.conf
V-22304 No Change
Findings ID: GEN000595 Rule ID: SV-63949r1_rule Severity: medium CCI: CCI-000196

Discussion

Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes more vulnerable to compromise.System Administrator

Checks

Check all password hashes in /etc/passwd or /etc/shadow begin with '$5$' or '$6$'.

Procedure:
# cut -d ':' -f2 /etc/passwd
# cut -d ':' -f2 /etc/shadow

Any password hashes present not beginning with '$5$' or, '$6$' is a finding. Any entries showing only NP, LK, or x are not findings.

Fix

Change the passwords for all accounts using non-compliant password hashes.

(This requires GEN000590 is already met.)
V-22305 No Change
Findings ID: GEN000610 Rule ID: SV-64065r1_rule Severity: medium CCI: CCI-000193

Discussion

To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use.System Administrator

Checks

Check /etc/pam.d/system-auth for lcredit setting.

Procedure:
Check the password lcredit option
# grep pam_cracklib.so /etc/pam.d/system-auth

Confirm the lcredit option is set to -1 as in the example:

password required pam_cracklib.so lcredit=-1

There may be other options on the line. If no such line is found, or the lcredit is not -1 this is a finding.

Fix

Edit "/etc/pam.d/system-auth" to include the line:

password required pam_cracklib.so lcredit=-1

prior to the "password include system-auth-ac" line.
V-22306 No Change
Findings ID: GEN000750 Rule ID: SV-64283r2_rule Severity: medium CCI: CCI-000195

Discussion

To ensure password changes are effective in their goals, the system must ensure that old and new passwords have significant differences. Without significant changes, new passwords may be easily guessed based on the value of a previously compromised password.System Administrator

Checks

Check /etc/pam.d/system-auth for a pam_cracklib parameter difok.

Procedure:
# grep difok /etc/pam.d/system-auth
If difok is not present, or has a value less than 8, this is a finding.

Check for system-auth-ac inclusions.
# grep -c system-auth-ac /etc/pam.d/*

If the system-auth-ac file is included anywhere
# more /etc/pam.d/system-auth-ac | grep difok

If system-auth-ac is included anywhere and difok is not present, or has a value less than 8, this is a finding.

Ensure the passwd command uses the system-auth settings.
# grep system-auth /etc/pam.d/passwd
If a line "password include system-auth" is not found then the password checks in system-auth will not be applied to new passwords.

Fix

If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth and add or edit a pam_cracklib entry with a difok parameter set equal to or greater than 8.
V-22307 No Change
Findings ID: GEN000790 Rule ID: SV-64303r1_rule Severity: medium CCI: CCI-000189

Discussion

An easily guessable password provides an open door to any external or internal malicious intruder. Many computer compromises occur as the result of account name and password guessing. This is generally done by someone with an automated script that uses repeated logon attempts until the correct account and password pair is guessed. Utilities, such as cracklib, can be used to validate passwords are not dictionary words and meet other criteria during password changes.System Administrator

Checks

Check /etc/pam.d/system-auth for pam_cracklib configuration.

Procedure:
# grep pam_cracklib /etc/pam.d/system-auth*
If pam_cracklib is not present. This is a finding.

If pam_cracklib is present only in /etc/pam.d/system-auth-ac:
ensure that /etc/pam.d/system-auth includes /etc/pam.d/system-auth-ac.
#grep system-auth-ac /etc/pam.d/system-auth

This should return:
auth include system-auth-ac
account include system-auth-ac
password include system-auth-ac
session include system-auth-ac

/etc/pam.d/system-auth-ac should only be included by /etc/pam.d/system-auth. All other pam files should include /etc/pam.d/system-auth.

If pam_cracklib is not defined in /etc/pam.d/system-auth either directly or through inclusion of system-auth-ac, this is a finding.

Ensure the passwd command uses the system-auth settings.
# grep system-auth /etc/pam.d/passwd

If a line "password include system-auth" is not found then the password checks in system-auth will not be applied to new passwords, this is a finding.

Fix

If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth and configure pam_cracklib by adding a line such as "password required pam_cracklib.so"
V-22308 No Change
Findings ID: GEN000850 Rule ID: SV-64327r1_rule Severity: low CCI: CCI-000009

Discussion

Configuring a supplemental group for users permitted to switch to the root user prevents unauthorized users from accessing the root account, even with knowledge of the root credentials.System Administrator

Checks

Check /etc/pam.d/su uses pam_wheel.
# grep pam_wheel /etc/pam.d/su

If pam_wheel is not present, or is commented out, this is a finding.

Fix

Edit /etc/pam.d/su and uncomment or add a line such as "auth required pam_wheel.so". If necessary, create a "wheel" group and add administrative users to the group.
V-22309 No Change
Findings ID: GEN000930 Rule ID: SV-64363r1_rule Severity: medium CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the UNIX permissions of the files.System Administrator

Checks

Check the root account's home directory has no extended ACL.

# find ~root -type d -prune -exec ls -ld {} \;

If the permissions include a '+' the directory has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the root account's home directory.
# setfacl --remove-all <root home directory>
V-22310 No Change
Findings ID: GEN000945 Rule ID: SV-64377r1_rule Severity: medium CCI: CCI-000366

Discussion

The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. Entries starting with a slash (/) are absolute paths.System Administrator

Checks

Check the LD_LIBRARY_PATH environment variable is empty or not defined for the root user.
# echo $LD_LIBRARY_PATH
If a path list is returned, this is a finding.

Fix

Edit the root user initialization files and remove any definition of LD_LIBRARY_PATH.
V-22311 No Change
Findings ID: GEN000950 Rule ID: SV-64383r1_rule Severity: medium CCI: CCI-000366

Discussion

The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries relative to the current working directory, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with (/) are absolute paths.System Administrator

Checks

Check the LD_PRELOAD environment variable is empty or not defined for the root user.
# echo $LD_PRELOAD
If a path list is returned, this is a finding.

Fix

Edit the root user initialization files and remove any definition of LD_PRELOAD.
V-22312 No Change
Findings ID: GEN001170 Rule ID: SV-64465r2_rule Severity: medium CCI: CCI-000366

Discussion

Files without a valid group owner may be unintentionally inherited if a group is assigned the same GID as the GID of the files without a valid group-owner.System Administrator

Checks

Search the system for files without a valid group-owner.
# find / -ignore_readdir_race -nogroup
If any files are found, this is a finding.

Fix

Change the group-owner for each file without a valid group-owner.
# chgrp avalidgroup /tmp/a-file-without-a-valid-group-owner
V-22313 No Change
Findings ID: GEN001190 Rule ID: SV-64473r1_rule Severity: medium CCI: CCI-000225

Discussion

Restricting permission on daemons will protect them from unauthorized modification and possible system compromise.System Administrator

Checks

Check network services daemon files have no extended ACLs.

# ls -la /usr/sbin

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Note: Network daemons not residing in these directories must also be checked.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /usr/sbin/*
V-22314 No Change
Findings ID: GEN001210 Rule ID: SV-64479r1_rule Severity: medium CCI: CCI-001499

Discussion

Restricting permissions will protect system command files from unauthorized modification. System command files include files present in directories used by the operating system for storing default system executables and files present in directories included in the system's default executable search paths.System Administrator

Checks

Check all system command files have no extended ACLs.
# ls -lL /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all [file with extended ACL]
V-22315 No Change
Findings ID: GEN001270 Rule ID: SV-64493r1_rule Severity: medium CCI: CCI-001314

Discussion

If the system log files are not protected, unauthorized users could change the logged data, eliminating its forensic value. Authorized software may be given log file access through the use of extended ACLs when needed and configured to provide the least privileges required.trueSystem Administrator

Checks

Verify system log files have no extended ACLs.

Procedure:
# ls -lL /var/log

If the permissions include a '+', the file has an extended ACL. If an extended ACL exists, verify with the SA if the ACL is required to support authorized software and provides the minimum necessary permissions. If an extended ACL exists, providing access beyond the needs of authorized software, this is a finding.

Fix

Remove the extended ACL from the file.

Procedure:
# setfacl --remove-all [file with extended ACL]
V-22316 No Change
Findings ID: GEN001290 Rule ID: SV-64521r2_rule Severity: low CCI: CCI-000225

Discussion

If manual pages are compromised, misleading information could be inserted, causing actions to compromise the system.System Administrator

Checks

Verify all manual page files have no extended ACLs.
# ls -lLR /usr/share/man /usr/share/info /usr/share/infopage

If the permissions include a '+', the file has an extended ACL this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /usr/share/man/* /usr/share/info/* /usr/share/infopage/*
V-22317 No Change
Findings ID: GEN001310 Rule ID: SV-64531r2_rule Severity: medium CCI: CCI-001499

Discussion

Unauthorized access could destroy the integrity of the library files.System Administrator

Checks

Verify system libraries have no extended ACLs.

# ls -lLR /usr/lib/ /lib/ /usr/lib64 /lib64 | grep "+ "

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and has not been approved by the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /usr/lib/* /lib/*
V-22318 No Change
Findings ID: GEN001361 Rule ID: SV-64503r1_rule Severity: medium CCI: CCI-000225

Discussion

NIS/NIS+/yp files are part of the system's identification and authentication processes and are critical to system security. ACLs on these files could result in unauthorized modification, which could compromise these processes and the system. System Administrator

Checks

Verify NIS/NIS+/yp files have no extended ACLs.
# ls -lL /var/yp/*
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /var/yp/*
V-22319 No Change
Findings ID: GEN001362 Rule ID: SV-64497r1_rule Severity: medium CCI: CCI-000225

Discussion

The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging.
System Administrator

Checks

Verify the /etc/resolv.conf file is owned by root.
# ls -l /etc/resolv.conf
If the file is not owned by root, this is a finding.

Fix

Change the owner of the /etc/resolv.conf file to root.
# chown root /etc/resolv.conf
V-22320 No Change
Findings ID: GEN001363 Rule ID: SV-64099r1_rule Severity: medium CCI: CCI-000225

Discussion

The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Check the group ownership of the resolv.conf file.

Procedure:
# ls -lL /etc/resolv.conf

If the file is not group-owned by root, bin, or sys, this is a finding.

Fix

Change the group-owner of the /etc/resolv.conf file to root, bin, or sys.

Procedure:
# chgrp root /etc/resolv.conf
V-22321 No Change
Findings ID: GEN001364 Rule ID: SV-64185r1_rule Severity: medium CCI: CCI-000225

Discussion

The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Check the mode of the /etc/resolv.conf file.
# ls -l /etc/resolv.conf
If the file mode is not 0644, this is a finding.

Fix

Change the mode of the /etc/resolv.conf file to 0644.
# chmod 0644 /etc/resolv.conf
V-22322 No Change
Findings ID: GEN001365 Rule ID: SV-64513r1_rule Severity: medium CCI: CCI-000225

Discussion

The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Verify /etc/resolv.conf has no extended ACL.
# ls -l /etc/resolv.conf

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/resolv.conf
V-22323 No Change
Findings ID: GEN001366 Rule ID: SV-64519r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Verify the /etc/hosts file is owned by root.
# ls -l /etc/hosts

If the file is not owned by root, this is a finding.

Fix

Change the owner of the /etc/hosts file to root.
# chown root /etc/hosts
V-22324 No Change
Findings ID: GEN001367 Rule ID: SV-64523r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Check the /etc/hosts file's group ownership.

Procedure:
# ls -lL /etc/hosts

If the file is not group-owned by root, bin, or sys, this is a finding.

Fix

Change the group-owner of the /etc/hosts file to root, sys, or bin.

Procedure:
# chgrp root /etc/hosts
V-22325 No Change
Findings ID: GEN001368 Rule ID: SV-64527r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Check the mode of the /etc/hosts file.
# ls -l /etc/hosts

If the file mode is not 0644, this is a finding.

Fix

Change the mode of the /etc/hosts file to 0644.

# chmod 0644 /etc/hosts
V-22326 No Change
Findings ID: GEN001369 Rule ID: SV-64533r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Verify /etc/hosts has no extended ACL.

# ls -l /etc/hosts

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/hosts
V-22327 No Change
Findings ID: GEN001371 Rule ID: SV-64535r1_rule Severity: medium CCI: CCI-000225

Discussion

The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.System Administrator

Checks

Verify the /etc/nsswitch.conf file is owned by root.

# ls -l /etc/nsswitch.conf

If the file is not owned by root, this is a finding.

Fix

Change the owner of the /etc/nsswitch.conf file to root.

# chown root /etc/nsswitch.conf
V-22328 No Change
Findings ID: GEN001372 Rule ID: SV-64539r1_rule Severity: medium CCI: CCI-000225

Discussion

The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.System Administrator

Checks

Check the group ownership of the nsswitch.conf file.

Procedure:
# ls -lL /etc/nsswitch.conf

If the file is not group-owned by root, bin or sys, this is a finding.

Fix

Change the group-owner of the /etc/nsswitch.conf file to root, bin or sys.

Procedure:
# chgrp root /etc/nsswitch.conf
V-22329 No Change
Findings ID: GEN001373 Rule ID: SV-64541r1_rule Severity: medium CCI: CCI-000225

Discussion

The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.System Administrator

Checks

Check the mode of the /etc/nsswitch.conf file.

# ls -l /etc/nsswitch.conf

If the file mode is not 0644, this is a finding.

Fix

Change the mode of the /etc/nsswitch.conf file to 0644 or less permissive.

# chmod 0644 /etc/nsswitch.conf
V-22330 No Change
Findings ID: GEN001374 Rule ID: SV-64545r1_rule Severity: medium CCI: CCI-000225

Discussion

The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.System Administrator

Checks

Verify /etc/nsswitch.conf has no extended ACL.

# ls -l /etc/nsswitch.conf

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/nsswitch.conf
V-22331 No Change
Findings ID: GEN001375 Rule ID: SV-64547r1_rule Severity: low CCI: CCI-001182

Discussion

To provide availability for name resolution services, multiple redundant name servers are mandated. A failure in name resolution could lead to the failure of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.System Administrator

Checks

Determine if DNS is enabled on the system.

# grep dns /etc/nsswitch.conf

If no line is returned, or any returned line is commented out, the system does not use DNS, and this is not applicable.

Determine the name servers used by the system.

# grep nameserver /etc/resolv.conf

If less than two lines are returned that are not commented out, this is a finding.

Fix

Edit /etc/resolv.conf and add additional "nameserver" lines until at least two are present.
V-22332 No Change
Findings ID: GEN001378 Rule ID: SV-64549r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification.System Administrator

Checks

Verify the /etc/passwd file is owned by root.

# ls -l /etc/passwd

If the file is not owned by root, this is a finding.

Fix

Change the owner of the /etc/passwd file to root.

# chown root /etc/passwd
V-22333 No Change
Findings ID: GEN001379 Rule ID: SV-64553r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification.System Administrator

Checks

Check the group ownership of the passwd file.

Procedure:
# ls -lL /etc/passwd

If the file is not group-owned by root, bin or sys, this is a finding.

Fix

Change the group-owner of the /etc/passwd file to root, bin or sys.

Procedure:
# chgrp root /etc/passwd
V-22334 No Change
Findings ID: GEN001390 Rule ID: SV-64559r1_rule Severity: medium CCI: CCI-000225

Discussion

File system ACLs can provide access to files beyond what is allowed by the mode numbers of the files. The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification.System Administrator

Checks

Verify /etc/passwd has no extended ACL.

# ls -l /etc/passwd

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/passwd
V-22335 No Change
Findings ID: GEN001391 Rule ID: SV-64561r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/group file is critical to system security and must be owned by a privileged user. The group file contains a list of system groups and associated information.System Administrator

Checks

Verify the /etc/group file is owned by root.

# ls -l /etc/group

If the file is not owned by root, this is a finding.

Fix

Change the owner of the /etc/group file to root.

# chown root /etc/group
V-22336 No Change
Findings ID: GEN001392 Rule ID: SV-64563r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information.System Administrator

Checks

Check the group ownership of the /etc/group file.

Procedure:
# ls -lL /etc/group

If the file is not group-owned by root, bin or sys, this is a finding.

Fix

Change the group-owner of the /etc/group file.

Procedure:
# chgrp root /etc/group
V-22337 No Change
Findings ID: GEN001393 Rule ID: SV-64565r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information.System Administrator

Checks

Check the mode of the /etc/group file.

# ls -l /etc/group

If the file mode is more permissive than 0644, this is a finding.

Fix

Change the mode of the /etc/group file to 0644 or less permissive.

# chmod 0644 /etc/group
V-22338 No Change
Findings ID: GEN001394 Rule ID: SV-64567r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information.System Administrator

Checks

Verify /etc/group has no extended ACL.

# ls -l /etc/group

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/group
V-22339 No Change
Findings ID: GEN001410 Rule ID: SV-64571r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root.System Administrator

Checks

Check the ownership of the /etc/shadow file.

Procedure:
# ls -lL /etc/shadow

If the file is not group-owned by root, bin, or sys, this is a finding.

Fix

Change the group-owner of the /etc/shadow file.

Procedure:
# chgrp root /etc/shadow
V-22340 No Change
Findings ID: GEN001430 Rule ID: SV-64575r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root.System Administrator

Checks

Verify /etc/shadow has no extended ACL.

# ls -l /etc/shadow

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/shadow
V-22341 No Change
Findings ID: GEN000000-LNX001431 Rule ID: SV-62667r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/gshadow file is critical to system security and must be owned by a privileged user. The /etc/gshadow file contains a list of system groups and hashes for group passwords.System Administrator

Checks

Check the /etc/gshadow file is owned by root.
# ls -l /etc/gshadow
If the file is not owned by root, this is a finding.

Fix

Change the owner of the /etc/gshadow file to root.
# chown root /etc/gshadow
V-22342 No Change
Findings ID: GEN000000-LNX001432 Rule ID: SV-62681r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/gshadow file is critical to system security and must be protected from unauthorized modification. The /etc/gshadow file contains a list of system groups and hashes for group passwords.System Administrator

Checks

Check the /etc/gshadow file is group-owned by root.
# ls -l /etc/gshadow
If the file is not group-owned by root, this is a finding.

Fix

Change the group-owner of the /etc/gshadow file to root.
# chgrp root /etc/gshadow
V-22343 No Change
Findings ID: GEN000000-LNX001433 Rule ID: SV-62697r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/gshadow file is critical to system security and must be protected from unauthorized modification. The /etc/gshadow file contains a list of system groups and hashes for group passwords.System Administrator

Checks

Check the mode of the /etc/gshadow file.
# ls -l /etc/gshadow
If the file mode is more permissive than 0400, this is a finding.

Fix

Change the mode of the /etc/gshadow file to 0400 or less permissive.
# chmod 0400 /etc/gshadow
V-22344 No Change
Findings ID: GEN000000-LNX001434 Rule ID: SV-62711r1_rule Severity: medium CCI: CCI-000225

Discussion

The /etc/gshadow file is critical to system security and must be protected from unauthorized modification. The /etc/gshadow file contains a list of system groups and hashes for group passwords.System Administrator

Checks

Check /etc/gshadow has no extended ACL.
# ls -l /etc/gshadow
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/gshadow
V-22347 No Change
Findings ID: GEN001470 Rule ID: SV-64581r1_rule Severity: medium CCI: CCI-000201

Discussion

If password hashes are readable by non-administrators, the passwords are subject to attack through lookup tables or cryptographic weaknesses in the hashes.System Administrator

Checks

Verify no password hashes are present in /etc/passwd.

# cut -d : -f 2 /etc/passwd | egrep -v '^(x|\*)$'

If any password hashes are returned, this is a finding.

Fix

Migrate /etc/passwd password hashes to /etc/shadow.

# pwconv
V-22348 No Change
Findings ID: GEN001475 Rule ID: SV-64583r1_rule Severity: medium CCI: CCI-000225

Discussion

Group passwords are typically shared and should not be used. Additionally, if password hashes are readable by non-administrators, the passwords are subject to attack through lookup tables or cryptographic weaknesses in the hashes.System Administrator

Checks

Check the /etc/group file for password hashes.

# cut -d : -f 2 /etc/group | egrep -v '^(x|!)$'

If any password hashes are returned, this is a finding.

Fix

Edit /etc/group and change the password field to an exclamation point (!) to lock the group password.
V-22349 No Change
Findings ID: GEN000000-LNX001476 Rule ID: SV-62767r1_rule Severity: medium CCI: CCI-000366

Discussion

Group passwords are typically shared and should not be used.System Administrator

Checks

Check the /etc/gshadow file for password hashes.
# cut -d : -f 2 /etc/gshadow | egrep -v '^(x|!!)$'
If any password hashes are returned, this is a finding.

Fix

Edit /etc/gshadow and change the password field to an exclamation point (!) to lock the group password.
V-22350 No Change
Findings ID: GEN001490 Rule ID: SV-64587r1_rule Severity: low CCI: CCI-000225

Discussion

Excessive permissions on home directories allow unauthorized access to user files.System Administrator

Checks

Verify user home directories have no extended ACLs.

# cut -d : -f 6 /etc/passwd | xargs -n1 ls -ld

If the permissions include a '+', the file has an extended ACL this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all [user home directory with extended ACL]
V-22351 No Change
Findings ID: GEN001550 Rule ID: SV-63833r1_rule Severity: medium CCI: CCI-000225

Discussion

If a user's files are group-owned by a group of which the user is not a member, unintended users may be able to access them.System Administrator

Checks

Check the contents of user home directories for files group-owned by a group of which the home directory's owner is not a member.
1. List the user accounts.
# cut -d : -f 1 /etc/passwd
2. For each user account, get a list of GIDs for files in the user's home directory.
# find ~username -printf %G\\n | sort | uniq
3. Obtain the list of GIDs where the user is a member.
# id -G username
4. Check the GID lists. If there are GIDs in the file list not present in the user list, this is a finding.

Fix

Change the group of a file not group-owned by a group of which the home directory's owner is a member.
# chgrp <group with user as member> <file with bad group ownership>
Document all changes.
V-22352 No Change
Findings ID: GEN001570 Rule ID: SV-63839r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions allow unauthorized access to user files.System Administrator

Checks

Check the contents of user home directories for files with extended ACLs.
# cut -d : -f 6 /etc/passwd | xargs -n1 -IDIR ls -alLR DIR
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all <user file with extended ACL>
V-22353 No Change
Findings ID: GEN001590 Rule ID: SV-63847r1_rule Severity: medium CCI: CCI-000225

Discussion

If the startup files are writable by other users, they could modify the startup files to insert malicious commands into the startup files.System Administrator

Checks

Verify run control scripts have no extended ACLs.
# ls -lL /etc/rc* /etc/init.d
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all <run control script with extended ACL>
V-22354 No Change
Findings ID: GEN001605 Rule ID: SV-63851r3_rule Severity: medium CCI: CCI-000366

Discussion

The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Verify run control scripts' library search paths.
# grep -r LD_LIBRARY_PATH /etc/rc* /etc/init.d

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the run control script and remove the relative path entries from the library search path variables that are not documented with the ISSO.

Remove any empty path entries that are defined in these files.
V-22355 No Change
Findings ID: GEN001610 Rule ID: SV-63853r3_rule Severity: medium CCI: CCI-000366

Discussion

The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If an entry begins with a character other than a slash (/), or has If this list contains paths to libraries to the current working directory that have not been authorized, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Verify run control scripts' library preload list.
# grep -r LD_PRELOAD /etc/rc* /etc/init.d

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the run control script and remove the relative path entries from the library preload variables that are not documented with the ISSO.

Remove any empty path entries that are defined in these files.
V-22356 No Change
Findings ID: GEN001730 Rule ID: SV-63867r1_rule Severity: medium CCI: CCI-000225

Discussion

Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.System Administrator

Checks

Check global initialization files for extended ACLs:

# ls -l /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|grep "\+ "

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# ls -l etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|grep "\+ "|sed "s/^.* \///g"|xargs setfacl --remove-all
V-22357 No Change
Findings ID: GEN001810 Rule ID: SV-63881r1_rule Severity: medium CCI: CCI-000225

Discussion

If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files.System Administrator

Checks

Check skeleton files for extended ACLs:

# ls -alL /etc/skel

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all [skeleton file with extended ACL]
or:
# ls -lL /etc/skel|grep "\+ "|sed "s/^.* \//|xargs setfacl --remove-all
will remove all ACLs from the files.
V-22358 No Change
Findings ID: GEN001830 Rule ID: SV-63323r1_rule Severity: medium CCI: CCI-000225

Discussion

If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files.System Administrator

Checks

Verify the skeleton files are group-owned by root.

Procedure:
# ls -alL /etc/skel
If a skeleton file is not group-owned by root, bin, sys, system, or other this is a finding.

Fix

Change the group-owner of the skeleton file to root, bin, sys, system, or other.

Procedure:
# chgrp <group> /etc/skel/[skeleton file]
or:
# ls -L /etc/skel|xargs stat -L -c %G:%n|egrep -v "^(root|bin|sy|sytem|other):"|cut -d: -f2|chgrp root
will change the group of all files not already one of the approved group to root.
V-22359 No Change
Findings ID: GEN001845 Rule ID: SV-63331r3_rule Severity: medium CCI: CCI-000366

Discussion

The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories, such as a leading or trailing colon, two consecutive colons, or a single period; this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Check the global initialization files' library search paths.

Procedure:
# grep LD_LIBRARY_PATH /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/*

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the global initialization file and remove the relative path entries from the library search path variables that have not been documented with the ISSO.

Remove any empty path entries that are defined in these files.
V-22360 No Change
Findings ID: GEN001850 Rule ID: SV-63335r3_rule Severity: medium CCI: CCI-000366

Discussion

The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If an entry begins with a character other than a slash (/), or has If this list contains paths to libraries to the current working directory that have not been authorized, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Check the global initialization files' library preload list.
# grep -r LD_PRELOAD /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/*

This variable is formatted as a colon-separated list of paths.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the global initialization file and remove the relative path entry from the library preload variable that has not been authorized by the ISSO.

Remove any empty path entries that are defined in these files.
V-22361 No Change
Findings ID: GEN001870 Rule ID: SV-63343r1_rule Severity: medium CCI: CCI-000225

Discussion

Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.System Administrator

Checks

Check user home directories for local initialization files group-owned by a group other than the user's primary group or root.

Procedure:
# FILES=" .login .cshrc .logout .profile .bash_profile .bashrc .bash_logout .env .dtprofile .dispatch .emacs .exrc";
# for PWLINE in `cut -d: -f4,6 /etc/passwd`; do HOMEDIR=$(echo ${PWLINE}|cut -d: -f2);GROUP=$(echo ${PWLINE} | cut -d: -f1);for INIFILE in $FILES;do stat -c %g/%G:%n ${HOMEDIR}/${INIFILE} 2>null|egrep -v "${GROUP}";done;done

If any file is not group-owned by root or the user's primary GID, this is a finding.

Fix

Change the group-owner of the local initialization file to the user's primary group, or root.
# chgrp <user's primary GID> <user's local initialization file>

Procedure:
# FILES=".bashrc .bash_login .bash_logout .bash_profile .cshrc .kshrc .login .logout .profile .tcshrc .env .dtprofile .dispatch .emacs .exrc";
# for PWLINE in `cut -d: -f4,6 /etc/passwd`; do HOMEDIR=$(echo ${PWLINE}|cut -d: -f2);GROUP=$(echo ${PWLINE} | cut -d: -f1);for INIFILE in $FILES;do MATCH=$(stat -c %g/%G:%n ${HOMEDIR}/${INIFILE} 2>null|egrep -c -v "${GROUP}");if [ $MATCH != 0 ] ; then chgrp ${GROUP} ${HOMEDIR}/${INIFILE};fi;done;done
V-22362 No Change
Findings ID: GEN001890 Rule ID: SV-63537r1_rule Severity: medium CCI: CCI-000225

Discussion

Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.System Administrator

Checks

Check user home directories for local initialization files with extended ACLs.
# cut -d : -f 6 /etc/passwd | xargs -n1 -IDIR ls -alL DIR/.bashrc DIR/.bash_login DIR/.bash_logout DIR/.bash_profile DIR/.cshrc DIR/.kshrc DIR/.login DIR/.logout DIR/.profile DIR/.env DIR/.dtprofile DIR/.dispatch DIR/.emacs DIR/.exrc
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all <local initialization file with extended ACL>
V-22363 No Change
Findings ID: GEN001901 Rule ID: SV-63549r3_rule Severity: medium CCI: CCI-000366

Discussion

The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories, such as a leading or trailing colon, two consecutive colons, or a single period this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Verify local initialization files have library search path containing only authorized paths.

Procedure:

NOTE: This must be done in the BASH shell.

# cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep -H LD_LIBRARY_PATH {} \;

This variable is formatted as a colon-separated list of directories.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the local initialization file and remove any relative path entries that have not been documented with the ISSO.

Remove any empty path entries that are defined in these files.
V-22364 No Change
Findings ID: GEN001902 Rule ID: SV-63569r3_rule Severity: medium CCI: CCI-000366

Discussion

The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If an entry begins with a character other than a slash (/), or has If this list contains paths to libraries to the current working directory that have not been authorized, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths.System Administrator

Checks

Verify local initialization files have library preload list containing only absolute paths.

NOTE: The following must be done in the BASH shell.

Procedure:
# cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep -H LD_PRELOAD {} \;

This variable is formatted as a colon-separated list of paths.

Such as a leading or trailing colon, two consecutive colons, or a single period this is a finding.

If an entry begins with a character other than a slash (/), or has not been documented with the ISSO, this is a finding.

Fix

Edit the local initialization file and remove any relative path entry from the library preload variable that has not been authorized by the ISSO.

Remove any empty path entries that are defined in these files.
V-22365 No Change
Findings ID: GEN002210 Rule ID: SV-63697r1_rule Severity: medium CCI: CCI-000225

Discussion

If shell files are group-owned by users other than root or a system group, they could be modified by intruders or malicious users to perform unauthorized actions.System Administrator

Checks

If /etc/shells exists, check the group ownership of each shell referenced.

Procedure:
# cat /etc/shells | xargs -n1 ls -l

Otherwise, check any shells found on the system.
Procedure:
# find / -name "*sh" | xargs -n1 ls -l

If a shell is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group-owner of the shell to root, bin, sys, or system.

Procedure:
# chgrp root <shell>
V-22366 No Change
Findings ID: GEN002230 Rule ID: SV-63017r1_rule Severity: medium CCI: CCI-000225

Discussion

Shells with world/group write permissions give the ability to maliciously modify the shell to obtain unauthorized access.System Administrator

Checks

If /etc/shells exists, check the permissions of each shell referenced.
# cat /etc/shells | xargs -n1 ls -lL

Otherwise, check any shells found on the system.
# find / -name "*sh" | xargs -n1 ls -lL

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all [shell]
V-22367 No Change
Findings ID: GEN002330 Rule ID: SV-63293r1_rule Severity: medium CCI: CCI-000225

Discussion

File system ACLs can provide access to files beyond what is allowed by the mode numbers of the files.System Administrator

Checks

Check the permissions of audio devices.
# ls -lL /dev/audio* /dev/snd/*
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all [device file]
V-22368 No Change
Findings ID: GEN002430 Rule ID: SV-63455r1_rule Severity: medium CCI: CCI-000366

Discussion

The "nodev" (or equivalent) mount option causes the system to not handle device files as system devices. This option must be used for mounting any file system not containing approved device files. Device files can provide direct access to system hardware and can compromise security if not protected.System Administrator

Checks

Check /etc/mtab and verify the "nodev" mount option is used on any filesystems mounted from removable media or network shares. If any filesystem mounted from removable media or network shares does not have this option, this is a finding.

Fix

Edit /etc/fstab and add the "nodev" option to any filesystems mounted from removable media or network shares.
V-22369 No Change
Findings ID: GEN002710 Rule ID: SV-63885r1_rule Severity: medium CCI: CCI-000163

Discussion

If a user can write to the audit logs, then audit trails can be modified or destroyed and system intrusion may not be detected.System Administrator

Checks

Check the system audit log files for extended ACLs.

Procedure:
# grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs ls -l

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the system audit file(s).
V-22370 No Change
Findings ID: GEN002715 Rule ID: SV-63959r1_rule Severity: low CCI: CCI-001493

Discussion

To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.System Administrator

Checks

Verify the audit tool executables are owned by root.
# ls -l /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd
If any listed file is not owned by root, this is a finding.

Fix

Change the owner of the audit tool executable to root.
# chown root [audit tool executable]
V-22371 No Change
Findings ID: GEN002716 Rule ID: SV-63975r1_rule Severity: low CCI: CCI-001493

Discussion

To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.System Administrator

Checks

Verify the audit tool executables are group-owned by root, bin, sys, or system.

Procedure:
# ls -lL /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd

If any listed file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group-owner of the audit tool executable to root, bin, sys, or system.

Procedure:
# chgrp root <audit tool executable>
V-22372 No Change
Findings ID: GEN002717 Rule ID: SV-64003r1_rule Severity: low CCI: CCI-001493

Discussion

To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.System Administrator

Checks

Check the mode of audit tool executables.
# ls -l /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd
If any listed file has a mode more permissive than 0750, this is a finding.

Fix

Change the mode of the audit tool executable to 0750, or less permissive.
# chmod 0750 [audit tool executable]
V-22373 No Change
Findings ID: GEN002718 Rule ID: SV-64097r1_rule Severity: low CCI: CCI-001493

Discussion

To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.System Administrator

Checks

Check the permissions of audit tool executables.
# ls -l /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd
If the permissions include a '+' the file has an extended ACL, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all [audit file]
V-22374 No Change
Findings ID: GEN002719 Rule ID: SV-64223r1_rule Severity: low CCI: CCI-000139

Discussion

An accurate and current audit trail is essential for maintaining a record of system activity. If the system fails, the SA must be notified and must take prompt action to correct the problem.

Minimally, the system must log this event and the SA will receive this notification during the daily system log review. If feasible, active alerting (such as e-mail or paging) should be employed consistent with the site's established operations management systems and procedures.System Administrator

Checks

Verify the /etc/audit/auditd.conf has the disk_full_action and disk_error_action parameters set.

Procedure:
# grep disk_full_action /etc/audit/auditd.conf

If the disk_full_action parameter is missing or set to "suspend" or "ignore" this is a finding.

# grep disk_error_action /etc/audit/auditd.conf

If the disk_error_action parameter is missing or set to "suspend" or "ignore" this is a finding.

Fix

Edit /etc/audit/auditd.conf and set the disk_full_action and/or disk_error_action parameters to a valid setting of "syslog", "exec", "single" or "halt", adding the parameters if necessary.
V-22375 No Change
Findings ID: GEN002730 Rule ID: SV-64261r1_rule Severity: medium CCI: CCI-000143

Discussion

An accurate and current audit trail is essential for maintaining a record of system activity. If the system fails, the SA must be notified and must take prompt action to correct the problem.

Minimally, the system must log this event and the SA will receive this notification during the daily system log review. If feasible, active alerting (such as e-mail or paging) should be employed consistent with the site's established operations management systems and procedures.System Administrator

Checks

Check /etc/audit/auditd.conf for the space_left_action and action_mail_accnt parameters. If the space_left_action or the action_mail_accnt parameters are set to blanks, this is a finding.

If the space_left_action is set to "syslog", the system logs the event, this is not a finding.

If the space_left_action is set to "exec", the system executes a designated script. If this script informs the SA of the event, this is not a finding.

If the space_left_action parameter is missing, this is a finding.
If the space_left_action parameter is set to "ignore" or "suspend" no logging would be performed after the event, this is a finding.
If the space_left_action parameter is set to "single" or "halt" this effectively stops the system causing a Denial of Service, this is a finding.

If the space_left_action is set to "email" and the action_mail_acct parameter is not set to the e-mail address of the system administrator, this is a finding. The action_mail_acct parameter, if missing, defaults to "root". Note that if the email address of the system administrator is on a remote system "sendmail" must be available.

Fix

Edit /etc/audit/auditd.conf and set the space_left_action parameter to a valid setting other than "ignore". If the space_left_action parameter is set to "email" set the action_mail_acct parameter to an e-mail address for the system administrator.
V-22376 No Change
Findings ID: GEN002750 Rule ID: SV-64267r1_rule Severity: low CCI: CCI-000018

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises, and damages incurred during a system compromise.System Administrator

Checks

Determine if execution of the useradd and groupadd executable are audited.
# auditctl -l | egrep '(useradd|groupadd)'
If either useradd or groupadd are not listed with a permissions filter of at least 'x', this is a finding.
Determine if /etc/passwd, /etc/shadow, /etc/group, and /etc/gshadow are audited for appending.
# auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow)'
If any of these are not listed with a permissions filter of at least 'a', this is a finding.

Fix

Configure execute auditing of the useradd and groupadd executables.
Add the following to audit.rules:
-w /usr/sbin/useradd -p x -k useradd
-w /usr/sbin/groupadd -p x -k groupadd
Configure append auditing of the passwd, shadow, group, and gshadow files. Add the following to audit.rules:
-w /etc/passwd -p a -k passwd
-w /etc/shadow -p a -k shadow
-w /etc/group -p a -k group
-w /etc/gshadow -p a -k gshadow
Restart the auditd service.
V-22377 No Change
Findings ID: GEN002751 Rule ID: SV-64269r1_rule Severity: low CCI: CCI-001403

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Determine if execution of the usermod and groupmod executable are audited.
# auditctl -l | egrep '(usermod|groupmod)'
If either useradd or groupadd are not listed with a permissions filter of at least 'w', this is a finding.
Determine if /etc/passwd, /etc/shadow, /etc/group, and /etc/gshadow are audited for writing.
# auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow)'
If any of these are not listed with a permissions filter of at least 'w', this is a finding.

Fix

Configure execute auditing of the usermod and groupmod executables. Add the following to the audit.rules file:
-w /usr/sbin/usermod -p x -k usermod
-w /usr/sbin/groupmod -p x -k groupmod
Configure append auditing of the passwd, shadow, group, and gshadow files. Add the following to the audit.rules file:
-w /etc/passwd -p w -k passwd
-w /etc/shadow -p w -k shadow
-w /etc/group -p w -k group
-w /etc/gshadow -p w -k gshadow
Restart the auditd service.
V-22378 No Change
Findings ID: GEN002752 Rule ID: SV-64271r1_rule Severity: low CCI: CCI-001404

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Determine if execution of the passwd executable is audited.
# auditctl -l | grep /usr/bin/passwd
If passwd is not listed with a permissions filter of at least 'x', this is a finding.

Fix

Configure execute auditing of the passwd executable. Add the following to the audit.rules file:
-w /usr/bin/passwd -p x -k passwd

Restart the auditd service.
V-22382 No Change
Findings ID: GEN002753 Rule ID: SV-64273r1_rule Severity: low CCI: CCI-001405

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Determine if execution of the userdel and groupdel executable are audited.
# auditctl -l | egrep '(userdel|groupdel)'
If either userdel or groupdel are not listed with a permissions filter of at least 'x', this is a finding.

Fix

Configure execute auditing of the userdel and groupdel executables. Add the following to the audit.rules file:
-w /usr/sbin/userdel -p x
-w /usr/sbin/groupdel -p x

Restart the auditd service.
V-22383 No Change
Findings ID: GEN002825 Rule ID: SV-64505r1_rule Severity: medium CCI: CCI-000126

Discussion

Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA.System Administrator

Checks

Determine if the init_module syscall is audited.

# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "init_module"

If the result does not contain "-S init_module", this is a finding.

Fix

The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.

On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.

Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.

The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.

Procedure:
Configure auditing of the init_module syscalls.
Add the following to the "etc/audit/audit.rules" or "etc/audit.rules" file:

-a exit,always -S init_module

Restart the auditd service.
# service auditd restart
V-22384 No Change
Findings ID: GEN002990 Rule ID: SV-64407r1_rule Severity: medium CCI: CCI-000225

Discussion

A readable and/or writeable cron.allow file by other users than root could allow potential intruders and malicious users to use the file contents to help discern information, such as who is allowed to execute cron programs, which could be harmful to overall system and network security.System Administrator

Checks

Check the permissions of the cron.allow file.
# ls -l /etc/cron.allow

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/cron.allow
V-22385 No Change
Findings ID: GEN003050 Rule ID: SV-64399r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.System Administrator

Checks

Check the group ownership of the crontab files.
Procedure:

# ls -lL /var/spool/cron

# ls -lL /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -lL /etc/cron*|grep -v deny

If the group owner is not root or the crontab owner's primary group, this is a finding.

Fix

Change the group owner of the crontab file to root, cron, or the crontab's primary group.

Procedure:
# chgrp root [crontab file]
V-22386 No Change
Findings ID: GEN003090 Rule ID: SV-64381r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. ACLs on crontab files may provide unauthorized access to the files.System Administrator

Checks

Check the permissions of the crontab files.
Procedure:

# ls -lL /var/spool/cron

# ls -lL /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -lL /etc/cron*|grep -v deny

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all [crontab file]
V-22387 No Change
Findings ID: GEN003110 Rule ID: SV-64367r1_rule Severity: medium CCI: CCI-000225

Discussion

To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. ACLs on cron and crontab directories may provide unauthorized access to these directories. Unauthorized modifications to these directories or their contents may result in the addition of unauthorized cron jobs or deny service to authorized cron jobs.System Administrator

Checks

Check the permissions of the crontab directories.

Procedure:
# ls -ld /var/spool/cron

# ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly
or
# ls -ld /etc/cron*|grep -v deny

If the permissions include a '+' the directory has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the directory.

# setfacl --remove-all <crontab directory>
V-22388 No Change
Findings ID: GEN003190 Rule ID: SV-64325r2_rule Severity: medium CCI: CCI-000225

Discussion

Cron logs contain reports of scheduled system activities and must be protected from unauthorized access or manipulation.System Administrator

Checks

Check the permissions of the file.

Procedure:

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Check the configured cron log file found in the cron entry in /etc/syslog.conf or /etc/rsyslog.conf(normally /var/log/cron).

# grep cron /etc/syslog.conf

Or:

# grep cron /etc/rsyslog.conf

# ls -lL /var/log/cron

If the permissions include a '+', the file has an extended ACL.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /var/log/cron
V-22389 No Change
Findings ID: GEN003210 Rule ID: SV-64331r1_rule Severity: medium CCI: CCI-000225

Discussion

If there are excessive file permissions for the cron.deny file, sensitive information could be viewed or edited by unauthorized users.System Administrator

Checks

Check the permissions of the file.

# ls -lL /etc/cron.deny

If the permissions include a '+', the file has an extended ACL.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/cron.deny
V-22390 No Change
Findings ID: GEN003245 Rule ID: SV-64347r1_rule Severity: medium CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Unauthorized modification of the at.allow file could result in Denial of Service to authorized "at" users and the granting of the ability to run "at" jobs to unauthorized users.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/at.allow
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/at.allow
V-22391 No Change
Findings ID: GEN003250 Rule ID: SV-64351r1_rule Severity: medium CCI: CCI-000225

Discussion

If the group of the cron.allow is not set to root, bin, sys, or cron, the possibility exists for an unauthorized user to view or edit the list of users permitted to use cron. Unauthorized modification of this file could cause Denial of Service to authorized cron users or provide unauthorized users with the ability to run cron jobs.System Administrator

Checks

Check the group ownership of the file.

Procedure:
# ls -lL /etc/cron.allow

If the file exists and is not group-owned by root, bin, sys or cron, this is a finding.

Fix

Change the group ownership of the file.

Procedure:
# chgrp root /etc/cron.allow
V-22392 No Change
Findings ID: GEN003252 Rule ID: SV-64355r1_rule Severity: medium CCI: CCI-000225

Discussion

The "at" daemon control files restrict access to scheduled job manipulation and must be protected. Unauthorized modification of the at.deny file could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/at.deny
If the file has a mode more permissive than 0600, this is a finding.

Fix

Change the mode of the file.
# chmod 0600 /etc/at.deny
V-22393 No Change
Findings ID: GEN003255 Rule ID: SV-64357r1_rule Severity: medium CCI: CCI-000225

Discussion

The "at" daemon control files restrict access to scheduled job manipulation and must be protected. Unauthorized modification of the at.deny file could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/at.deny
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/at.deny
V-22394 No Change
Findings ID: GEN003270 Rule ID: SV-64365r1_rule Severity: medium CCI: CCI-000225

Discussion

Cron daemon control files restrict the scheduling of automated tasks and must be protected. Unauthorized modification of the cron.deny file could result in Denial of Service to authorized cron users or could provide unauthorized users with the ability to run cron jobs.System Administrator

Checks

Check the group ownership of the file.

Procedure:
# ls -lL /etc/cron.deny

If the file is not group-owned by root, bin, or sys, this is a finding.

Fix

Change the group ownership of the file.
# chgrp root /etc/cron.deny
V-22395 No Change
Findings ID: GEN003410 Rule ID: SV-64289r1_rule Severity: medium CCI: CCI-000225

Discussion

If the "at" directory has an extended ACL, unauthorized users could be allowed to view or to edit files containing sensitive information within the "at" directory. Unauthorized modifications could result in Denial of Service to authorized "at" jobs.System Administrator

Checks

Check the permissions of the directory.
# ls -lLd /var/spool/at
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the directory.
# setfacl --remove-all /var/spool/at
V-22396 No Change
Findings ID: GEN003430 Rule ID: SV-64297r1_rule Severity: medium CCI: CCI-000225

Discussion

If the group of the "at" directory is not root, bin, sys, or cron, unauthorized users could be allowed to view or edit files containing sensitive information within the directory.System Administrator

Checks

Check the group ownership of the file.

Procedure:
# ls -lL /var/spool/at

If the file is not group-owned by root, bin, sys, daemon or cron, this is a finding.

Fix

Change the group ownership of the file to root, bin, sys, daemon or cron.

Procedure:
# chgrp <root or other system group> <"at" directory>
V-22397 No Change
Findings ID: GEN003470 Rule ID: SV-64413r1_rule Severity: medium CCI: CCI-000225

Discussion

If the group owner of the at.allow file is not set to root, bin, sys, or cron, unauthorized users could be allowed to view or edit the list of users permitted to run "at" jobs. Unauthorized modification could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs.System Administrator

Checks

Check the group ownership of the file.

Procedure:
# ls -lL /etc/at.allow

If the file is not group-owned by root, bin, sys, or cron, this is a finding.

Fix

Change the group ownership of the file.

Procedure:
# chgrp root /etc/at.allow
V-22398 No Change
Findings ID: GEN003490 Rule ID: SV-64309r1_rule Severity: medium CCI: CCI-000225

Discussion

If the group owner of the at.deny file is not set to root, bin, sys, or cron, unauthorized users could be allowed to view or edit sensitive information contained within the file. Unauthorized modification could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs.System Administrator

Checks

Check the group ownership of the file.

Procedure:
# ls -lL /etc/at.deny

If the file is not group-owned by root, bin, sys, or cron, this is a finding.

Fix

Change the group ownership of the at.deny file to root, sys, bin, or cron.

Procedure:
# chgrp root /etc/at.deny
V-22404 No Change
Findings ID: GEN003510 Rule ID: SV-64421r1_rule Severity: medium CCI: CCI-000366

Discussion

Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps may consume a considerable amount of disk space and may result in Denial of Service by exhausting the available space on the target file system. The kernel core dump process may increase the amount of time a system is unavailable due to a crash. Kernel core dumps can be useful for kernel debugging.System Administrator

Checks

Verify the kdump service is not running.

Procedure:
# service kdump status
If "Kdump is operational" is returned, this is a finding.

Fix

Disable kdump.
# service kdump stop
# chkconfig kdump off
V-22405 No Change
Findings ID: GEN003521 Rule ID: SV-64431r1_rule Severity: low CCI: CCI-000225

Discussion

Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the kernel core dump data directory is not group-owned by a system group, the core dumps contained in the directory may be subject to unauthorized access.System Administrator

Checks

Determine the kernel core dump data directory and check its ownership.

Procedure:
Examine /etc/kdump.conf. The "path" parameter, which defaults to /var/crash, determines the path relative to the crash dump device. The crash device is specified with a filesystem type and device, such as "ext3 /dev/sda2". Using this information, determine where this path is currently mounted on the system.

# ls -ld <kernel dump data directory>

If the directory is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group-owner of the kernel core dump data directory.

# chgrp root <kernel core dump data directory>
V-22406 No Change
Findings ID: GEN003522 Rule ID: SV-64433r2_rule Severity: low CCI: CCI-000225

Discussion

Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the mode of the kernel core dump data directory is more permissive than 0700, unauthorized users may be able to view or to modify kernel core dump data files.System Administrator

Checks

Verify the location of the kernel core dump data directory:
# grep “path” /etc/kdump.conf

Note: If this setting is not configured or commented out, the default kernel dump data directory is /var/crash.

Check the permissions of the dump data directory:
# ls -ld <path to kernel core dump data directory>

If the directory has a mode more permissive than 0700, this is a finding.

Fix

Set the permissions on the kernel core dump data directory to 0700.

# chmod 0700 <kernel core dump data directory>
V-22407 No Change
Findings ID: GEN003523 Rule ID: SV-64437r2_rule Severity: low CCI: CCI-000225

Discussion

Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If there is an extended ACL for the kernel core dump data directory, unauthorized users may be able to view or to modify kernel core dump data files.System Administrator

Checks

Determine the kernel core dump data directory and check its permissions.

Procedure:
Verify the location of the kernel core dump data directory:
# grep “path” /etc/kdump.conf

Note: If this setting is not configured or commented out, the default kernel dump data directory is /var/crash.

Check the permissions of the dump data directory:
# ls -ld <path to kernel core dump data directory>

If the permissions include a '+', the directory has an extended ACL. If the directory has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the directory.

# setfacl --remove-all <path to kernel core dump data directory>
V-22408 No Change
Findings ID: GEN003581 Rule ID: SV-64443r1_rule Severity: medium CCI: CCI-000225

Discussion

Configuration of network interfaces should be limited to privileged users. Manipulation of network interfaces may result in a Denial of Service or bypass of network security mechanisms.System Administrator

Checks

Check the system for user-controlled network interfaces.
# grep -l '^USERCTL=yes' /etc/sysconfig/network-scripts/ifcfg*
If any results are returned, this is a finding.

Fix

Edit the configuration for the user-controlled interface and remove the "USERCTL=yes" configuration line or set to "USERCTL=no".
V-22409 No Change
Findings ID: GEN003602 Rule ID: SV-64445r2_rule Severity: low CCI: CCI-001551

Discussion

The processing of (ICMP) timestamp requests increases the attack surface of the system.System Administrator

Checks

Verify the system does not respond to ICMP TIMESTAMP-REQUESTs

Procedure:
# grep "timestamp" /etc/sysconfig/iptables

This should return entries for "timestamp-reply" and "timestamp-request". Both should end with "-j DROP'. If either does not exist or does not "DROP" the message, this is a finding.

Fix

Configure the system to not respond to ICMP TIMESTAMP-REQUESTs. This is done by rejecting ICMP type 13 and 14 messages at the firewall.

Procedure:
Edit /etc/sysconfig/iptables to add:

-A RH-Firewall-1-INPUT -p ICMP --icmp-type timestamp-request -j DROP
-A RH-Firewall-1-INPUT -p ICMP --icmp-type timestamp-reply -j DROP

Restart the firewall:
# service iptables restart
V-22410 No Change
Findings ID: GEN003603 Rule ID: SV-64459r1_rule Severity: medium CCI: CCI-001551

Discussion

Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.System Administrator

Checks

Verify the system does not respond to ICMP ECHO_REQUESTs set to broadcast addresses.

Procedure:
# cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

If the result is not 1, this is a finding.

Fix

Configure the system to not respond to ICMP ECHO_REQUESTs sent to broadcast addresses. Edit /etc/sysctl.conf and add a setting for "net.ipv4.icmp_echo_ignore_broadcasts=1" and reload the sysctls.

Procedure:
# echo "net.ipv4.icmp_echo_ignore_broadcasts=1" >> /etc/sysctl.conf
# sysctl -p
V-22411 No Change
Findings ID: GEN003604 Rule ID: SV-64195r2_rule Severity: medium CCI: CCI-001551

Discussion

The processing of (ICMP) timestamp requests increases the attack surface of the system. Responding to broadcast ICMP timestamp requests facilitates network mapping and provides a vector for amplification attacks.GEN000000-FWThe system's firewall default-deny policy mitigates the risk from this vulnerability.System Administrator

Checks

Verify the system does not respond to ICMP TIMESTAMP_REQUESTs set to broadcast addresses.

Procedure:
# cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

If the result is not 1, this is a finding.

Note: The same parameter controls both ICMP ECHO_REQUESTs and TIMESTAMP_REQUESTs.

Fix

Configure the system to not respond to ICMP TIMESTAMP_REQUESTs sent to broadcast addresses. Edit /etc/sysctl.conf and add a setting for "net.ipv4.icmp_echo_ignore_broadcasts=1" and reload the sysctls.

Procedure:
# echo "net.ipv4.icmp_echo_ignore_broadcasts=1" >> /etc/sysctl.conf
# sysctl -p
V-22414 No Change
Findings ID: GEN003607 Rule ID: SV-64197r1_rule Severity: medium CCI: CCI-001551

Discussion

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the handling of source-routed traffic destined to the system itself, not to traffic forwarded by the system to another system, such as when IPv4 forwarding is enabled and the system is functioning as a router.System Administrator

Checks

Verify the system does not accept source-routed IPv4 packets.

Procedure:
# grep [01] /proc/sys/net/ipv4/conf/*/accept_source_route|egrep "default|all"

If all of the resulting lines do not end with "0", this is a finding.

Fix

Configure the system to not accept source-routed IPv4 packets.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_source_route=0" and "net.ipv4.conf.default.accept_source_route=0".

Reload the sysctls.
Procedure:
# sysctl -p
V-22415 No Change
Findings ID: GEN003608 Rule ID: SV-64201r1_rule Severity: medium CCI: CCI-001551

Discussion

Proxy ARP allows a system to respond to ARP requests on one interface on behalf of hosts connected to another interface. If this function is enabled when not required, addressing information may be leaked between the attached network segments.System Administrator

Checks

Verify the system does not use proxy ARP.

# grep [01] /proc/sys/net/ipv4/conf/*/proxy_arp|egrep "default|all"

If all of the resulting lines do not end with "0", this is a finding.

Fix

Configure the system to not use proxy ARP.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.proxy_arp=0" and "net.ipv4.conf.default.proxy_arp=0".
# sysctl -p
V-22416 No Change
Findings ID: GEN003609 Rule ID: SV-64203r1_rule Severity: medium CCI: CCI-001503

Discussion

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.System Administrator

Checks

Verify the system does not accept IPv4 ICMP redirect messages.

# grep [01] /proc/sys/net/ipv4/conf/*/accept_redirects|egrep "default|all"

If all of the resulting lines do not end with "0", this is a finding.

Fix

Configure the system to not accept IPv4 ICMP redirect messages.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_redirects=0" and "net.ipv4.conf.default.accept_redirects=0".
# sysctl -p
V-22417 No Change
Findings ID: GEN003610 Rule ID: SV-64205r1_rule Severity: medium CCI: CCI-001551

Discussion

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.System Administrator

Checks

Verify the system does not send IPv4 ICMP redirect messages.

# grep [01] /proc/sys/net/ipv4/conf/*/send_redirects|egrep "default|all"

If all of the resulting lines do not end with "0", this is a finding.

Fix

Configure the system to not send IPv4 ICMP redirect messages.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.send_redirects=0" and "net.ipv4.conf.default.send_redirects=0".
# sysctl -p
V-22418 No Change
Findings ID: GEN003611 Rule ID: SV-64207r1_rule Severity: low CCI: CCI-000126

Discussion

Martian packets are packets containing addresses known by the system to be invalid. Logging these messages allows the SA to identify misconfigurations or attacks in progress.System Administrator

Checks

Verify the system logs martian packets.

# grep [01] /proc/sys/net/ipv4/conf/*/log_martians|egrep "default|all"

If all of the resulting lines do not end with "1", this is a finding.

Fix

Configure the system to log martian packets.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.log_martians=1" and "net.ipv4.conf.default.log_martians=1".

Reload the sysctls.
Procedure:
# sysctl -p
V-22419 No Change
Findings ID: GEN003612 Rule ID: SV-64209r1_rule Severity: medium CCI: CCI-001092

Discussion

A TCP SYN flood attack can cause Denial of Service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies are a mechanism used to only track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This technique does not operate in a fully standards-compliant manner, but is only activated when a flood condition is detected, and allows defense of the system while continuing to service valid requests.System Administrator

Checks

Verify the system configured to use TCP syncookies when experiencing a TCP SYN flood.
# cat /proc/sys/net/ipv4/tcp_syncookies
If the result is not "1", this is a finding.

Fix

Configure the system to use TCP syncookies when experiencing a TCP SYN flood.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.tcp_syncookies=1".
# sysctl -p
V-22421 No Change
Findings ID: GEN003619 Rule ID: SV-64213r1_rule Severity: medium CCI: CCI-001551

Discussion

Some systems have the ability to bridge or switch frames (link-layer forwarding) between multiple interfaces. This can be useful in a variety of situations but, if enabled when not needed, has the potential to bypass network partitioning and security.System Administrator

Checks

Verify the system is not configured for bridging.
# ls /proc/sys/net/bridge
If the directory exists, this is a finding.
# lsmod | grep '^bridge '
If any results are returned, this is a finding.

Fix Text: Configure the system to not use bridging.

Fix

Configure the system to not use bridging.
# rmmod bridge
Edit /etc/modprobe.conf and add a line such as "install bridge /bin/false" to prevent the loading of the bridge module.
V-22422 No Change
Findings ID: GEN003650 Rule ID: SV-64227r1_rule Severity: low CCI: CCI-000553

Discussion

File system journaling, or logging, can allow reconstruction of file system data after a system crash preserving the integrity of data that may have otherwise been lost. Journaling file systems typically do not require consistency checks upon booting after a crash, which can improve system availability. Some file systems employ other mechanisms to ensure consistency also satisfying this requirement.System Administrator

Checks

Verify local filesystems use journaling.
# mount | grep '^/dev/' | egrep -v 'type (ext3|ext4|jfs|reiserfs|xfs|iso9660|udf)'
If a mount is listed, this is a finding.

Fix

Convert local file systems to use journaling or another mechanism ensuring file system consistency.
V-22423 No Change
Findings ID: GEN003730 Rule ID: SV-64235r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of sensitive files or utilities to system groups may provide unauthorized users with the potential to access sensitive information or change the system configuration possibly weakening the system's security posture.System Administrator

Checks

Check the group ownership of the xinetd configuration files and directories.

Procedure:
# ls -alL /etc/xinetd.conf /etc/xinetd.d

If a file or directory is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group-owner of the xinetd configuration files and directories.

Procedure:
# chgrp -R root /etc/xinetd.conf /etc/xinetd.d
V-22424 No Change
Findings ID: GEN003745 Rule ID: SV-64241r1_rule Severity: medium CCI: CCI-000225

Discussion

The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system.System Administrator

Checks

Check the permissions of the xinetd configuration files.

Procedure:
# ls -alL /etc/xinetd.conf
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/xinetd.conf
V-22425 No Change
Findings ID: GEN003750 Rule ID: SV-64243r1_rule Severity: medium CCI: CCI-000225

Discussion

The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system.System Administrator

Checks

Check the permissions of the xinetd configuration directories.
# ls -dlL /etc/xinetd.d
If the mode of the directory is more permissive than 0755, this is a finding.

Fix

Change the mode of the directory.
# chmod 0755 /etc/xinetd.d
V-22426 No Change
Findings ID: GEN003755 Rule ID: SV-63971r1_rule Severity: medium CCI: CCI-000225

Discussion

The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system.System Administrator

Checks

Check the permissions of the xinetd configuration files and directories.
# ls -alL /etc/xinetd.conf /etc/xinetd.d
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/xinetd.d
V-22427 No Change
Findings ID: GEN003770 Rule ID: SV-63979r2_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give ownership of system configuration files to root or a system group provides the designated owner and unauthorized users with the potential to change the system configuration possibly weakening the system's security posture.System Administrator

Checks

Check the group ownership of the services file.

Procedure:
# ls -lL /etc/services

If the file is not group-owned by root or bin, this is a finding.

Fix

Change the group-owner of the services file.

Procedure:
# chgrp root /etc/services
V-22428 No Change
Findings ID: GEN003790 Rule ID: SV-63985r1_rule Severity: medium CCI: CCI-000225

Discussion

The services file is critical to the proper operation of network services and must be protected from unauthorized modification. If the services file has an extended ACL, it may be possible for unauthorized users to modify the file. Unauthorized modification could result in the failure of network services.System Administrator

Checks

Check the permissions of the /etc/services file.
# ls -lL /etc/services
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/services
V-22429 No Change
Findings ID: GEN003810 Rule ID: SV-63995r1_rule Severity: medium CCI: CCI-001336

Discussion

The portmap and rpcbind services increase the attack surface of the system and should only be used when needed. The portmap or rpcbind services are used by a variety of services using Remote Procedure Calls (RPCs).System Administrator

Checks

Check the status of the portmap service.
# service portmap status
If the service is running, this is a finding.

Fix

Shutdown and disable the portmap service.
# service portmap stop; chkconfig portmap off
V-22430 No Change
Findings ID: GEN003815 Rule ID: SV-63997r1_rule Severity: medium CCI: CCI-000305

Discussion

The portmap and rpcbind services increase the attack surface of the system and should only be used when needed. The portmap or rpcbind services are used by a variety of services using Remote Procedure Calls (RPCs).System Administrator

Checks

Check if the portmap package is installed.
# rpm -qa | grep portmap
If a package is found, this is a finding.

Fix

Remove the portmap package.
# rpm -e portmap
or
# yum remove portmap
V-22431 No Change
Findings ID: GEN003825 Rule ID: SV-64009r1_rule Severity: medium CCI: CCI-000305

Discussion

The rshd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.System Administrator

Checks

Check if the rsh-server package is installed.

Procedure:
# rpm -qa | grep rsh-server

If a package is found, this is a finding.

Fix

Remove the rsh-server package.

Procedure:
# rpm -e rsh-server
V-22432 No Change
Findings ID: GEN003830 Rule ID: SV-64019r1_rule Severity: medium CCI: CCI-000068

Discussion

The rlogind process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.System Administrator

Checks

Check the rlogind configuration.
# cat /etc/xinetd.d/rlogin
If the file exists and does not contain "disable = yes" this is a finding.

Fix

Remove or disable the rlogin configuration and restart xinetd.
# rm /etc/xinetd.d/rlogin ; service xinetd restart
V-22433 No Change
Findings ID: GEN003835 Rule ID: SV-64015r1_rule Severity: medium CCI: CCI-000305

Discussion

The rlogind process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.System Administrator

Checks

Check if the rsh-server package is installed.

Procedure:
# rpm -qa | grep rsh-server

If a package is found, this is a finding.

Fix

Remove the rsh-server package.

Procedure:
# rpm -e rsh-server
V-22434 No Change
Findings ID: GEN003845 Rule ID: SV-64039r1_rule Severity: medium CCI: CCI-000305

Discussion

The rexecd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.System Administrator

Checks

Check if the rsh-server package is installed.

Procedure:
# rpm -qa | grep rsh-server

If a package is found, this is a finding.

Fix

Remove the rsh-server package.

Procedure:
# rpm -e rsh-server
V-22435 No Change
Findings ID: GEN003930 Rule ID: SV-64117r2_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give group-ownership of the hosts.lpd file to root, bin, sys, or system provides the members of the owning group and possible unauthorized users, with the potential to modify the hosts.lpd file. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.System Administrator

Checks

Check the group ownership of the /etc/cups/printers.conf file.

Procedure:
# ls -lL /etc/cups/printers.conf

If the file is not group-owned by lp, this is a finding.

Fix

Change the group-owner of the printers.conf file.

Procedure:
# chgrp lp /etc/cups/printers.conf
V-22436 No Change
Findings ID: GEN003950 Rule ID: SV-63475r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the hosts.lpd (or equivalent) file may permit unauthorized modification. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.System Administrator

Checks

Check the permissions of the /etc/cups/printers.conf file.

# ls -lL /etc/cups/printers.conf

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/cups/printers.conf
V-22437 No Change
Findings ID: GEN004010 Rule ID: SV-63539r1_rule Severity: medium CCI: CCI-000225

Discussion

If an extended ACL exists on the traceroute executable file, it may provide unauthorized users with access to the file. Malicious code could be inserted by an attacker and triggered whenever the traceroute command is executed by authorized users. Additionally, if an unauthorized user is granted executable permissions to the traceroute command, it could be used to gain information about the network topology behind the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise.System Administrator

Checks

Check the permissions of the /bin/traceroute file.
# ls -lL /bin/traceroute
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /bin/traceroute
V-22438 No Change
Findings ID: GEN004370 Rule ID: SV-63613r1_rule Severity: medium CCI: CCI-000225

Discussion

If the alias file is not group-owned by root or a system group, an unauthorized user may modify the file adding aliases to run malicious code or redirect e-mail.System Administrator

Checks

If the "sendmail" and "postfix" packages are not installed, this is not applicable.

Check the group ownership of the alias files.

Procedure:
for sendmail:
# ls -lL /etc/aliases
If the files are not group-owned by root, this is a finding.

# ls -lL /etc/aliases.db
If the file is not group-owned by the same system group as sendmail, which is smmsp by default, this is a finding.

for postfix:
Verify the location of the alias file.
# postconf alias maps

This will return the location of the "aliases" file, by default "/etc/postfix/aliases"

# ls -lL <postfix aliases file>
If the files are not group-owned by root, this is a finding.

# ls -lL <postfix aliases.db file>
If the file is not group-owned by root, this is a finding.

Fix

Change the group-owner of the /etc/aliases file.

Procedure:
for sendmail:
# chgrp root /etc/aliases
# chgrp smmsp /etc/aliases.db

The aliases.db file must be owned by the same system group as sendmail, which is smmsp by default.

for postfix
# chgrp root /etc/postfix/aliases
# chgrp root /etc/postfix/aliases.db
V-22439 No Change
Findings ID: GEN004390 Rule ID: SV-63643r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect e-mail.System Administrator

Checks

If the "sendmail" and "postfix" packages are not installed, this is not applicable.

Check the permissions of the alias file.

Procedure:
for sendmail:
# ls -lL /etc/aliases /etc/aliases.db

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

for postfix:
Verify the location of the alias file.
# postconf alias maps

This will return the location of the "aliases" file, by default "/etc/postfix/aliases"

# ls -lL <postfix aliases file> <postfix aliases.db file>

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended permissions from the alias files.
Procedure:
for sendmail:
# setfacl --remove-all /etc/aliases /etc/aliases.db

for postfix (assuming the default postfix directory):
# setfacl --remove-all /etc/postfix/aliases /etc/postfix/aliases.db
V-22440 No Change
Findings ID: GEN004410 Rule ID: SV-63719r1_rule Severity: medium CCI: CCI-000225

Discussion

If a file executed through a mail aliases file is not group-owned by root or a system group, it may be subject to unauthorized modification. Unauthorized modification of files executed through aliases may allow unauthorized users to attain root privileges.System Administrator

Checks

Examine the contents of the /etc/aliases file.

Procedure:
# more /etc/aliases
Examine the aliases file for any utilized directories or paths.

# ls -lL <file referenced from aliases>

Check the permissions for any paths referenced.

If the group owner of any file is not root, bin, sys, or system, this is a finding.

Fix

Change the group ownership of the file referenced from /etc/aliases.

Procedure:
# chgrp root <file referenced from aliases>
V-22441 No Change
Findings ID: GEN004430 Rule ID: SV-63745r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on files executed through a mail aliases file could result in modification by an unauthorized user, execution of malicious code, and/or system compromise.System Administrator

Checks

Examine the contents of the /etc/aliases file.

Procedure:
# more /etc/aliases
Examine the aliases file for any utilized directories or paths.

# ls -lL <file referenced from aliases>

Check the permissions for any paths referenced.

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all <file referenced from aliases>
V-22442 No Change
Findings ID: GEN004510 Rule ID: SV-63755r3_rule Severity: medium CCI: CCI-000225

Discussion

If the SMTP service log file has an extended ACL, unauthorized users may be allowed to access or to modify the log file.System Administrator

Checks

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

Examine /etc/syslog.conf or /etc/rsyslog.conf and determine the log file(s) receiving logs for "mail.crit", "mail.debug", mail.*, or "*.crit".

Procedure:

This check is applicable to both Postfix or sendmail servers.

Check the permissions on these log files.

Identify any log files configured for "*.crit" and the "mail" service (excluding mail.none) and at any severity level.

For syslog:

# egrep "(\*.crit|mail\.[^n][^/]*)" /etc/syslog.conf|sed 's/^[^/]*//'|xargs ls -lL

For rsyslog:

# egrep "(\*.crit|mail\.[^n][^/]*)" /etc/rsyslog.conf|sed 's/^[^/]*//'|xargs ls -lL

If the permissions include a '+', the file has an extended ACL.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

This fix is applicable to both Postfix and sendmail servers.

Remove the extended ACL from the file.

# setfacl --remove-all <log file>
V-22444 No Change
Findings ID: GEN004930 Rule ID: SV-63015r1_rule Severity: medium CCI: CCI-000225

Discussion

If the ftpusers file is not group-owned by root or a system group, an unauthorized user may modify the file to allow unauthorized accounts to use FTP.System Administrator

Checks

Check the group ownership of the ftpusers file.

Procedure:
# ls -lL /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers

If the file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group owner of the ftpusers file.

Procedure:
# chgrp root /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers
V-22445 No Change
Findings ID: GEN004950 Rule ID: SV-63083r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service.System Administrator

Checks

Check the permissions of the /etc/ftpusers file.
# ls -lL /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers
V-22446 No Change
Findings ID: GEN005190 Rule ID: SV-63285r1_rule Severity: medium CCI: CCI-000225

Discussion

.Xauthority files ensure the user is authorized to access specific X Windows host. Extended ACLs may permit unauthorized modification of these files, which could lead to Denial of Service to authorized access or allow unauthorized access to be obtained.System Administrator

Checks

Check the file permissions for the .Xauthority files. These files will be located in user home directories.

Procedure:
# ls -la ~username |egrep "(\.Xauthority|\.xauth)"

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all .Xauthority
V-22447 No Change
Findings ID: GEN005305 Rule ID: SV-63397r1_rule Severity: medium CCI: CCI-001435

Discussion

SNMP Versions 1 and 2 are not considered secure. Without the strong authentication and privacy provided by the SNMP Version 3 User-based Security Model (USM), an attacker or other unauthorized users may gain access to detailed system management information and use the information to launch attacks against the system.System Administrator

Checks

Check the SNMP daemon is not configured to use the v1 or v2c security models.

Procedure:
Examine the default install location /etc/snmpd.conf
or:
# find / -name snmpd.conf

# grep -E '(v1|v2c|community|com2sec)' <snmp.conf file> | grep -v '^#'
If any configuration is found, this is a finding.

Fix

Edit /etc/snmpd.conf and remove references to the "v1", "v2c", "community", or "com2sec".

Restart the SNMP service.
# service snmpd restart
V-22448 No Change
Findings ID: GEN005306 Rule ID: SV-63407r1_rule Severity: medium CCI: CCI-001453

Discussion

The SNMP service must use SHA-1 or a FIPS 140-2 approved successor for authentication and integrity.System Administrator

Checks

Verify the SNMP daemon uses SHA for SNMPv3 users.

Procedure:
Examine the default install location /etc/snmp/snmpd.conf
or:
# find / -name snmpd.conf

# grep -v '^#' <snmpd.conf file> | grep -i createuser | grep -vi SHA
If any line is present this is a finding.

Fix

Edit /etc/snmp/snmpd.conf and add the SHA keyword for any create user statement without one.

Restart the SNMP service.
# service snmpd restart
V-22449 No Change
Findings ID: GEN005307 Rule ID: SV-63415r1_rule Severity: medium CCI: CCI-000068

Discussion

The SNMP service must use AES or a FIPS 140-2 approved successor algorithm for protecting the privacy of communications.System Administrator

Checks

Verify the SNMP daemon uses AES for SNMPv3 users.

Procedure:
Examine the default install location /etc/snmp/snmpd.conf
or:
# find / -name snmpd.conf

# grep -v '^#' <snmpd.conf file> | grep -i createuser | grep -vi AES

If any line is present this is a finding.

Fix

Edit /etc/snmp/snmpd.conf and add the AES keyword for any create user statement without one.

Restart the SNMP service.
# service snmpd restart
V-22450 No Change
Findings ID: GEN005350 Rule ID: SV-63437r1_rule Severity: medium CCI: CCI-000225

Discussion

The ability to read the MIB file could impart special knowledge to an intruder or malicious user about the ability to extract compromising information about the system or network.System Administrator

Checks

Check the file permissions for the MIB files.
# find / -name *.mib
# ls -lL <mib file>

If the permissions include a '+', the file has an extended ACL.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all <mib file>
V-22451 No Change
Findings ID: GEN005365 Rule ID: SV-63461r1_rule Severity: medium CCI: CCI-000225

Discussion

The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. If the file is not group-owned by a system group, it may be subject to access and modification from unauthorized users.System Administrator

Checks

Check the group ownership of the SNMP configuration file.

Procedure:
Examine the default install location /etc/snmp/snmpd.conf
or:
# find / -name snmpd.conf

# ls -lL <snmpd.conf>

If the file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group ownership of the SNMP configuration file.

Procedure:
# chgrp root <snmpd.conf>
V-22452 No Change
Findings ID: GEN005375 Rule ID: SV-63463r1_rule Severity: medium CCI: CCI-000225

Discussion

The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification.System Administrator

Checks

Check the permissions of the SNMP configuration file.

Procedure:
Examine the default install location /etc/snmp/snmpd.conf
or:
# find / -name snmpd.conf

# ls -lL <snmpd.conf>

If the permissions include a '+', the file has an extended ACL.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all <snmpd.conf file>
V-22453 No Change
Findings ID: GEN005390 Rule ID: SV-63467r2_rule Severity: medium CCI: CCI-000225

Discussion

Unauthorized users must not be allowed to access or modify the /etc/syslog.conf file.System Administrator

Checks

Check the permissions of the syslog configuration file.

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

# ls -lL /etc/syslog.conf

Or:

# ls -lL /etc/rsyslog.conf

If the mode of the file is more permissive than 0640, this is a finding.

Fix

Change the permissions of the syslog or rsyslog configuration file.

# chmod 0640 /etc/syslog.conf

Or:

# chmod 0640 /etc/rsyslog.conf
V-22454 No Change
Findings ID: GEN005395 Rule ID: SV-63471r2_rule Severity: medium CCI: CCI-000225

Discussion

Unauthorized users must not be allowed to access or modify the /etc/syslog.conf file.System Administrator

Checks

Check the permissions of the syslog configuration file.

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

# ls -lL /etc/syslog.conf

Or:

# ls -lL /etc/rsyslog.conf

If the permissions include a '+', the file has an extended ACL.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.

# setfacl --remove-all /etc/syslog.conf

Or:

# setfacl -- remove-all /etc/rsyslog.conf
V-22455 No Change
Findings ID: GEN005450 Rule ID: SV-63501r2_rule Severity: medium CCI: CCI-000136

Discussion

A syslog server (loghost) receives syslog messages from one or more systems. This data can be used as an authoritative log source in the event a system is compromised and its local logs are suspect.System Administrator

Checks

Check the syslog configuration file for remote syslog servers.

Depending on what system is used for log processing either /etc/syslog.conf or /etc/rsyslog.conf will be the logging configuration file.

# grep '@' /etc/syslog.conf | grep -v '^#'

Or:

# grep '@' /etc/rsyslog.conf | grep -v '^#'

If no line is returned, this is a finding.

Fix

Edit the syslog or rsyslog configuration file and add an appropriate remote syslog server.
V-22456 No Change
Findings ID: GEN005501 Rule ID: SV-63547r1_rule Severity: medium CCI: CCI-001436

Discussion

SSHv1 is not a DoD-approved protocol and has many well-known vulnerability exploits. Exploits of the SSH client could provide access to the system with the privileges of the user running the client.System Administrator

Checks

Check the SSH client configuration for allowed protocol versions.
# grep -i protocol /etc/ssh/ssh_config | grep -v '^#'
If the returned protocol configuration allows versions less than 2, this is a finding.

Fix

Edit the /etc/ssh/ssh_config file and add or edit a "Protocol" configuration line not allowing versions less than 2.
V-22457 No Change
Findings ID: GEN005504 Rule ID: SV-63553r1_rule Severity: medium CCI: CCI-000069

Discussion

The SSH daemon should only listen on network addresses designated for management traffic. If the system has multiple network interfaces and SSH listens on addresses not designated for management traffic, the SSH service could be subject to unauthorized access. If SSH is used for purposes other than management, such as providing an SFTP service, the list of approved listening addresses may be documented.trueSystem Administrator

Checks

Ask the SA to identify which interfaces on the system are designated for management traffic. If all interfaces on the system are authorized for management traffic, this is not applicable.

Check the SSH daemon configuration for listening network addresses.

# grep -i Listen /etc/ssh/sshd_config | grep -v '^#'

If no configuration is returned, or if a returned 'Listen' configuration contains addresses not designated for management traffic, this is a finding.

Fix

Edit the SSH daemon configuration to specify listening network addresses designated for management traffic.

Restart the SSH daemon.
# /sbin/service sshd restart
V-22458 No Change
Findings ID: GEN005505 Rule ID: SV-63561r2_rule Severity: medium CCI: CCI-000068

Discussion

DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES.System Administrator

Checks

Check the SSH daemon configuration for allowed ciphers.

# grep -i ciphers /etc/ssh/sshd_config | grep -v '^#'

If no lines are returned, or the returned ciphers list contains any cipher not starting with "3des" or "aes", this is a finding.

Fix

Edit the SSH daemon configuration and remove any ciphers not starting with "3des" or "aes" and remove any ciphers ending with "cbc".

If necessary, add a "Ciphers" line.

Ciphers aes256-ctr,aes192-ctr,aes128-ctr

Restart the SSH daemon.

# /sbin/service sshd restart
V-22459 No Change
Findings ID: GEN005506 Rule ID: SV-63567r1_rule Severity: medium CCI: CCI-000366

Discussion

The Cipher-Block Chaining (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen plain text attacks and must not be used.

System Administrator

Checks

Check the SSH daemon configuration for allowed ciphers.
# grep -i ciphers /etc/ssh/sshd_config | grep -v '^#'
If no lines are returned, or the returned ciphers list contains any cipher ending with cbc, this is a finding.

Fix

Edit /etc/ssh/sshd_config and add or edit the "Ciphers" line. Only include ciphers that start with "3des" or "aes" and do not contain "cbc". For the list of available ciphers for the particular version of your software, consult the sshd_config manpage.

Restart the SSH daemon.
V-22460 No Change
Findings ID: GEN005507 Rule ID: SV-63587r2_rule Severity: medium CCI: CCI-001453

Discussion

DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions.System Administrator

Checks

Check the SSH daemon configuration for allowed MACs.

Procedure:
# grep -i macs /etc/ssh/sshd_config | grep -v '^#'

If no lines are returned, or the returned MACs list contains any MAC that is not hmac-sha1 or a better hmac algorithm that is on the FIPS 140-2 approved list, this is a finding.

Fix

Edit the SSH daemon configuration and remove any MACs that are not hmac-sha1 or a better hmac algorithm that is on the FIPS 140-2 approved list. If necessary, add a MACs line.

Restart the SSH daemon.
# /sbin/service sshd restart
V-22461 No Change
Findings ID: GEN005510 Rule ID: SV-63593r1_rule Severity: medium CCI: CCI-000068

Discussion

DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES.System Administrator

Checks

Check the SSH client configuration for allowed ciphers.

# grep -i ciphers /etc/ssh/ssh_config | grep -v '^#'

If no lines are returned, or the returned ciphers list contains any cipher not starting with "3des" or "aes", this is a finding.

Fix

Edit the SSH client configuration and remove any ciphers not starting with "3des" or "aes" and remove any ciphers ending with "cbc". If necessary, add a "Ciphers" line.
V-22462 No Change
Findings ID: GEN005511 Rule ID: SV-63595r1_rule Severity: medium CCI: CCI-000366

Discussion

The (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen-plaintext attacks and must not be used.
System Administrator

Checks

Check the SSH client configuration for allowed ciphers.

# grep -i ciphers /etc/ssh/ssh_config | grep -v '^#'

If no lines are returned, or the returned ciphers list contains any cipher ending with "cbc", this is a finding.

Fix

Edit the SSH client configuration and remove any ciphers not starting with "3des" or "aes" and remove any ciphers ending with "cbc". If necessary, add a "Ciphers" line.
V-22463 No Change
Findings ID: GEN005512 Rule ID: SV-63669r2_rule Severity: medium CCI: CCI-001453

Discussion

DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions.System Administrator

Checks

Check the SSH client configuration for allowed MACs.

# grep -i macs /etc/ssh/ssh_config | grep -v '^#'

If no lines are returned, or the returned MACs list contains any MAC that is not hmac-sha1 or a better hmac algorithm that is on the FIPS 140-2 approved list, this is a finding.

Fix

Edit the SSH client configuration and remove any MACs that are not hmac-sha1 or a better hmac algorithm that is on the FIPS 140-2 approved list.

If necessary, add a MACs line.
V-22470 No Change
Findings ID: GEN005521 Rule ID: SV-63727r1_rule Severity: medium CCI: CCI-000225

Discussion

Restricting SSH logins to a limited group of users, such as system administrators, prevents password-guessing and other SSH attacks from reaching system accounts and other accounts not authorized for SSH access.System Administrator

Checks

There are two ways in which access to SSH may restrict users or groups.

Check if /etc/pam.d/sshd is configured to require daemon style login control.

# grep pam_access.so /etc/pam.d/sshd|grep "required"|grep "account"| grep -v '^#'

If no lines are returned, sshd is not configured to use pam_access.

Check the SSH daemon configuration for the AllowGroups setting.

# egrep -i "AllowGroups|AllowUsers" /etc/ssh/sshd_config | grep -v '^#'

If no lines are returned, sshd is not configured to limit access to users/groups.

If sshd is not configured to limit access either through pam_access or the use "AllowUsers" or "AllowGroups", this is a finding.

Fix

Edit the SSH daemon configuration and add an "AllowGroups" or "AllowUsers" directive specifying the groups and users allowed to have access.

Restart the SSH daemon.
# /sbin/service sshd restart

Alternatively, modify the /etc/pam.d/sshd file to include the line

account required pam_access.so accessfile=<path to access.conf for sshd>

If the "accessfile" option is not specified the default "access.conf" file will be used.

The "access.conf" file must contain the user restriction definitions.
V-22471 No Change
Findings ID: GEN005522 Rule ID: SV-63841r1_rule Severity: medium CCI: CCI-000225

Discussion

If a public host key file is modified by an unauthorized user, the SSH service may be compromised.System Administrator

Checks

Check the permissions for SSH public host key files.

# ls -lL /etc/ssh/*key.pub

If any file has a mode more permissive than 0644, this is a finding.

Fix

Change the permissions for the SSH public host key files.

# chmod 0644 /etc/ssh/*key.pub
V-22472 No Change
Findings ID: GEN005523 Rule ID: SV-63863r1_rule Severity: medium CCI: CCI-000225

Discussion

If an unauthorized user obtains the private SSH host key file, the host could be impersonated.System Administrator

Checks

Check the permissions for SSH private host key files.

# ls -lL /etc/ssh/*key

If any file has a mode more permissive than 0600, this is a finding.

Fix

Change the permissions for the SSH private host key files.

# chmod 0600 /etc/ssh/*key
V-22473 No Change
Findings ID: GEN005524 Rule ID: SV-63877r1_rule Severity: low CCI: CCI-000366

Discussion

GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed.System Administrator

Checks

Ask the SA if GSSAPI authentication is used for SSH authentication to the system. If so, this is not applicable.

Check the SSH daemon configuration for the GSSAPIAuthentication setting.

# grep -i GSSAPIAuthentication /etc/ssh/sshd_config | grep -v '^#'

If no lines are returned, or the setting is set to "yes", this is a finding.

Fix

Edit the SSH daemon configuration and set (add if necessary) a "GSSAPIAuthentication" directive set to "no".

Restart the SSH daemon.
# /sbin/service sshd restart
V-22474 No Change
Findings ID: GEN005525 Rule ID: SV-63953r1_rule Severity: low CCI: CCI-000366

Discussion

GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed.System Administrator

Checks

The default setting for GSSAPIAuthentication is "no".

Check for a change from the default.

# grep -i GSSAPIAuthentication /etc/ssh/ssh_config | grep -v '^#'

If the setting is "yes" this is a finding.

Fix

Edit the SSH client configuration and set the GSSAPIAuthentication" directive set to "no".
V-22475 No Change
Findings ID: GEN005526 Rule ID: SV-64033r1_rule Severity: low CCI: CCI-000366

Discussion

Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled for systems not using this capability.
System Administrator

Checks

Ask the SA if Kerberos authentication is used by the system. If it is, this is not applicable.

Check the SSH daemon configuration for the KerberosAuthentication setting.

# grep -i KerberosAuthentication /etc/ssh/sshd_config | grep -v '^#'

If no lines are returned, or the setting is set to "yes", this is a finding.

Fix

Edit the SSH daemon configuration and set (add if necessary) the "KerberosAuthentication" directive set to "no".

Restart the SSH daemon.
# /sbin/service sshd restart
V-22485 No Change
Findings ID: GEN005536 Rule ID: SV-64067r1_rule Severity: medium CCI: CCI-000225

Discussion

If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.System Administrator

Checks

Check the SSH daemon configuration for the StrictModes setting.

# grep -i StrictModes /etc/ssh/sshd_config | grep -v '^#'

If the setting is not present, or not set to "yes", this is a finding.

Fix

Edit the SSH daemon configuration and add or edit the "StrictModes" setting value to "yes".

Restart the SSH daemon.
# /sbin/service sshd restart
V-22486 No Change
Findings ID: GEN005537 Rule ID: SV-64073r1_rule Severity: medium CCI: CCI-000225

Discussion

SSH daemon privilege separation causes the SSH process to drop root privileges when not needed, which would decrease the impact of software vulnerabilities in the unprivileged section.System Administrator

Checks

Check the SSH daemon configuration for the UsePrivilegeSeparation setting.

# grep -i UsePrivilegeSeparation /etc/ssh/sshd_config | grep -v '^#'

If the setting is not present, or not set to "yes", this is a finding.

Fix

Edit the SSH daemon configuration and add or edit the "UsePrivilegeSeparation" setting value to "yes".

Restart the SSH daemon.
# /sbin/service sshd restart
V-22487 No Change
Findings ID: GEN005538 Rule ID: SV-64081r1_rule Severity: medium CCI: CCI-000366

Discussion

If SSH permits rhosts RSA authentication, a user may be able to log in based on the keys of the host originating the request and not any user-specific authentication.System Administrator

Checks

Check the SSH daemon configuration for the RhostsRSAAuthentication setting.

# grep -i RhostsRSAAuthentication /etc/ssh/sshd_config | grep -v '^#'

If the setting is set to "yes", this is a finding.

Fix

Edit the SSH daemon configuration and add or edit the "RhostsRSAAuthentication" setting value to "no".

Restart the SSH daemon.
# /sbin/service sshd restart
V-22488 No Change
Findings ID: GEN005539 Rule ID: SV-64089r1_rule Severity: medium CCI: CCI-000366

Discussion

If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.System Administrator

Checks

Check the SSH daemon configuration for the compression setting.

# grep -i Compression /etc/ssh/sshd_config | egrep "no|delayed"

If the setting is missing or is commented out, this is a finding.

If the setting is present but is not set to "no" or "delayed", this is a finding.

Fix

Edit the SSH daemon configuration and add or edit the "Compression" setting value to "no" or "delayed".

Restart the SSH daemon.
# /sbin/service sshd restart
V-22489 No Change
Findings ID: GEN005550 Rule ID: SV-64103r1_rule Severity: medium CCI: CCI-000048

Discussion

Failure to display the DoD logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.

The SSH service must be configured to display the DoD logon warning banner either through the SSH configuration or a wrapper program such as TCP_WRAPPERS.

The SSH daemon may also be used to provide SFTP service. The warning banner configuration for SSH will apply to SFTP.System Administrator

Checks

Verify the SSH daemon is configured for logon warning banners.

Procedure:
An exact match is required to have a valid warning banner. Check for the following login banner.

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.

Fix

Edit /etc/issue and the DoD login banner.

DoD Login Banners:
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.

Find the location of the banner file for sshd and examine the content:

# grep -i banner /etc/ssh/sshd_config | grep -v '^#'
# cat

Edit the SSH daemon configuration and add or edit a "Banner" setting referencing a file containing a logon warning banner.

Restart the SSH daemon.
# /sbin/service sshd restart
V-22490 No Change
Findings ID: GEN005570 Rule ID: SV-64107r1_rule Severity: medium CCI: CCI-000366

Discussion

If a system has no default gateway defined, the system is at increased risk of man-in-the-middle, monitoring, and Denial of Service attacks.System Administrator

Checks

Check for a default route for IPv6. If the system is a VM host and acts as a router solely for the benefit of its client systems, then this rule is not applicable.

# ip -6 route list | grep default

If the system uses IPv6, and no results are returned, this is a finding.

Fix

Add a default route for IPv6.

Edit /etc/sysconfig/network-scripts/ifcfg-eth0 (substitute interface as appropriate).

Add an IPV6_DEFAULTGW=<gateway> configuration setting.
Restart the interface.

# ifdown eth0; ifup eth0
V-22491 No Change
Findings ID: GEN005610 Rule ID: SV-64245r1_rule Severity: medium CCI: CCI-000366

Discussion

If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices.System Administrator

Checks

Check if the system is configured for IPv6 forwarding.

# grep [01] /proc/sys/net/ipv6/conf/*/forwarding|egrep "default|all"

If the /proc/sys/net/ipv6/conf/*/forwarding entries do not exist because of compliance with GEN007720, this is not a finding.

If all of the resulting lines do not end with 0, this is a finding.

Fix

Disable IPv6 forwarding.

Edit /etc/sysctl.conf and add a setting for "net.ipv6.conf.all.forwarding=0" and "net.ipv6.conf.default.forwarding=0".

Reload the sysctls.
Procedure:
# sysctl -p
V-22492 No Change
Findings ID: GEN005750 Rule ID: SV-64211r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give group-ownership of the NFS export configuration file to root or a system group provides the designated group-owner and possible unauthorized users with the potential to change system configuration which could weaken the system's security posture.System Administrator

Checks

Check the group ownership of the NFS export configuration file.

Procedure:
# ls -lL /etc/exports

If the file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group ownership of the NFS export configuration file.

Procedure:
# chgrp root /etc/exports
V-22493 No Change
Findings ID: GEN005770 Rule ID: SV-64191r1_rule Severity: low CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the NFS export configuration file could allow unauthorized modification of the file, which could result in Denial of Service to authorized NFS exports and the creation of additional unauthorized exports.System Administrator

Checks

Check the permissions of the NFS export configuration file.
# ls -lL /etc/exports
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/exports
V-22496 No Change
Findings ID: GEN005810 Rule ID: SV-64181r1_rule Severity: medium CCI: CCI-000225

Discussion

Failure to give group-ownership of sensitive files or directories to root provides the members of the owning group with the potential to access sensitive information or change system configuration which could weaken the system's security posture.System Administrator

Checks

List the exports.
# cat /etc/exports
For each file system displayed, check the ownership.

# ls -ldL <exported file system path>

If the directory is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group owner of the export directory.
# chgrp root <export>
V-22497 No Change
Findings ID: GEN006150 Rule ID: SV-64085r1_rule Severity: medium CCI: CCI-000225

Discussion

Excessive permissions could endanger the security of the Samba configuration file and, ultimately, the system and network.System Administrator

Checks

Check the permissions of the Samba configuration file.
# ls -lL /etc/samba/smb.conf
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/samba/smb.conf
V-22498 No Change
Findings ID: GEN006210 Rule ID: SV-64061r1_rule Severity: medium CCI: CCI-000225

Discussion

If the permissions of the "smbpasswd" file are too permissive, it may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.System Administrator

Checks

Check the permissions of the Samba password files.

Procedure:
# ls -lL /etc/samba/passdb.tdb /etc/samba/secrets.tdb

If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/samba/passdb.tdb /etc/samba/secrets.tdb
V-22499 No Change
Findings ID: GEN006225 Rule ID: SV-64049r1_rule Severity: medium CCI: CCI-000366

Discussion

Samba share authentication does not provide for individual user identification and must not be used.System Administrator

Checks

Check the security mode of the Samba configuration.
# grep -i security /etc/samba/smb.conf
If the security mode is "share", this is a finding.

Fix

Edit the "/etc/samba/smb.conf" file and change the "security" setting to "user" or another valid setting other than "share".
V-22500 No Change
Findings ID: GEN006230 Rule ID: SV-64041r1_rule Severity: medium CCI: CCI-000366

Discussion

Samba must be configured to protect authenticators. If Samba passwords are not encrypted for storage, plain-text user passwords may be read by those with access to the Samba password file.System Administrator

Checks

If the "samba-common" package is not installed, this is not applicable.

Check the encryption setting of Samba.

# grep -i 'encrypt passwords' /etc/samba/smb.conf

If the setting is not present, or not set to 'yes', this is a finding.

Fix

Edit the "/etc/samba/smb.conf" file and change the "encrypt passwords" setting to "yes".
V-22501 No Change
Findings ID: GEN006235 Rule ID: SV-64013r1_rule Severity: medium CCI: CCI-000366

Discussion

Guest access to shares permits anonymous access and is not permitted.System Administrator

Checks

Check the access to shares for Samba.
# grep -i 'guest ok' /etc/samba/smb.conf
If the setting exists and is set to 'yes', this is a finding.

Fix

Edit the "/etc/samba/smb.conf" file and change the "guest ok" setting to "no".
V-22502 No Change
Findings ID: GEN006270 Rule ID: SV-63925r1_rule Severity: medium CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the "incoming.conf" file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/news/incoming.conf
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/news/incoming.conf
V-22503 No Change
Findings ID: GEN006290 Rule ID: SV-63915r1_rule Severity: medium CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the hosts.nntp.nolimit file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.System Administrator

Checks

Check the permissions for "/etc/news/hosts.nntp.nolimit".

# ls -lL /etc/news/hosts.nntp.nolimit
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/news/hosts.nntp.nolimit
V-22504 No Change
Findings ID: GEN006310 Rule ID: SV-63901r1_rule Severity: medium CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the nnrp.access file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/news/nnrp.access
If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/news/nnrp.access
V-22505 No Change
Findings ID: GEN006330 Rule ID: SV-63835r1_rule Severity: medium CCI: CCI-000225

Discussion

Extended ACLs may provide excessive permissions on the /etc/news/passwd.nntp file, which may permit unauthorized access or modification to the NNTP configuration.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/news/passwd.nntp
If the mode includes a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/news/passwd.nntp
V-22506 No Change
Findings ID: GEN006565 Rule ID: SV-63667r1_rule Severity: medium CCI: CCI-000366

Discussion

Verification using the system package management tool can be used to determine that system software has not been tampered with.

This requirement is not applicable to systems not using package management tools.System Administrator

Checks

Check the root crontab (crontab -l) and the global crontabs in "/etc/crontab", "/etc/cron.*" for the presence of an rpm verification command such as:
rpm -qVa | awk '$2!="c" {print $0}'
If no such cron job is found, this is a finding.
If the result of the cron job indicates packages which do not pass verification exist, this is a finding unless the changes were made due to another STIG entry.

Fix

Add a cron job to run an rpm verification command such as:
rpm -qVa | awk '$2!="c" {print $0}'

For packages which failed verification:
If the package is not necessary for operations, remove it from the system.

If the package is necessary for operations, re-install the package.
V-22507 No Change
Findings ID: GEN006570 Rule ID: SV-63657r1_rule Severity: low CCI: CCI-001297

Discussion

ACLs can provide permissions beyond those permitted through the file mode and must be verified by file integrity tools.System Administrator

Checks

If using an Advanced Intrusion Detection Environment (AIDE), verify that the configuration contains the "ACL" option for all monitored files and directories.

Procedure:
Check for the default location /etc/aide/aide.conf
or:
# find / -name aide.conf

# egrep "[+]?acl" <aide.conf file>
If the option is not present. This is a finding.

If using a different file integrity tool, check the configuration per tool documentation.

Fix

If using AIDE, edit the configuration and add the "ACL" option for all monitored files and directories.

If using a different file integrity tool, configure ACL checking per the tool's documentation.
V-22508 No Change
Findings ID: GEN006571 Rule ID: SV-63631r1_rule Severity: low CCI: CCI-001297

Discussion

Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.System Administrator

Checks

If using an Advanced Intrusion Detection Environment (AIDE), verify the configuration contains the "xattrs" option for all monitored files and directories.

Procedure:
Check for the default location /etc/aide/aide.conf
or:
# find / -name aide.conf

# egrep "[+]?xattrs" <aide.conf file>

If the option is not present. This is a finding.

If using a different file integrity tool, check the configuration per tool documentation.

Fix

If using AIDE, edit the configuration and add the "xattrs" option for all monitored files and directories.

If using a different file integrity tool, configure extended attributes checking per the tool's documentation.
V-22509 No Change
Findings ID: GEN006575 Rule ID: SV-63653r1_rule Severity: low CCI: CCI-001297

Discussion

File integrity tools often use cryptographic hashes for verifying that file contents have not been altered. These hashes must be FIPS 140-2 approved.System Administrator

Checks

If using an Advanced Intrusion Detection Environment (AIDE), verify the configuration contains the "sha256" or "sha512" options for all monitored files and directories.

Procedure:
Check for the default location /etc/aide/aide.conf
or:
# find / -name aide.conf

# egrep "[+]?(sha256|sha512)" <aide.conf file>
If the option is not present. This is a finding.
If one of these options is not present. This is a finding.

If using a different file integrity tool, check the configuration per tool documentation.

Fix

If using AIDE, edit the configuration and add the "sha512" option for all monitored files and directories.

If using a different file integrity tool, configure FIPS 140-2 approved cryptographic hashes per the tool's documentation.
V-22511 No Change
Findings ID: GEN007020 Rule ID: SV-63529r1_rule Severity: medium CCI: CCI-000382

Discussion

The Stream Control Transmission Protocol (SCTP) is an Internet Engineering Task Force (IETF)-standardized transport layer protocol. This protocol is not yet widely used. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.System Administrator

Checks

Verify the SCTP protocol handler is prevented from dynamic loading.
# grep 'install sctp /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.

Fix

Prevent the SCTP protocol handler for dynamic loading.
# echo "install sctp /bin/true" >> /etc/modprobe.conf
V-22514 No Change
Findings ID: GEN007080 Rule ID: SV-63521r1_rule Severity: medium CCI: CCI-000382

Discussion

The DCCP is a proposed transport layer protocol. This protocol is not yet widely used. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.System Administrator

Checks

Verify the DCCP protocol handler is prevented from dynamic loading.
# grep 'install dccp /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.
# grep 'install dccp_ipv4 /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.
# grep 'install dccp_ipv6 /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.

Fix

Prevent the DCCP protocol handler for dynamic loading.
# echo "install dccp /bin/true" >> /etc/modprobe.conf
# echo "install dccp_ipv4 /bin/true" >> /etc/modprobe.conf
# echo "install dccp_ipv6 /bin/true" >> /etc/modprobe.conf
V-22524 No Change
Findings ID: GEN007260 Rule ID: SV-63453r1_rule Severity: medium CCI: CCI-000382

Discussion

The AppleTalk suite of protocols is no longer in common use. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.System Administrator

Checks

Verify the AppleTalk protocol handler is prevented from dynamic loading.
# grep 'install appletalk' /etc/modprobe.conf /etc/modprobe.d/*
If anything is returned check that appletalk is disabled by having the executable set to '/bin/true'. If an uncommented line containing "appletalk" is found which has not been disabled, this is a finding.

Fix

Prevent the AppleTalk protocol handler for dynamic loading.
# echo "install appletalk /bin/true" >> /etc/modprobe.conf
V-22530 No Change
Findings ID: GEN007480 Rule ID: SV-63451r1_rule Severity: medium CCI: CCI-000382

Discussion

The RDS protocol is a relatively new protocol developed by Oracle for communication between the nodes of a cluster. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.System Administrator

Checks

Ask the SA if RDS is required by application software running on the system. If so, this is not applicable.

Verify the RDS protocol handler is prevented from dynamic loading.
# grep 'install rds /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.

Fix

Prevent the RDS protocol handler for dynamic loading.
# echo "install rds /bin/true" >> /etc/modprobe.conf
V-22533 No Change
Findings ID: GEN007540 Rule ID: SV-63449r1_rule Severity: medium CCI: CCI-000382

Discussion

The TIPC protocol is a relatively new cluster communications protocol developed by Ericsson. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.System Administrator

Checks

Verify the TIPC protocol handler is prevented from dynamic loading.
# grep 'install tipc /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.

Fix

Prevent the TIPC protocol handler for dynamic loading.
# echo "install tipc /bin/true" >> /etc/modprobe.conf
V-22539 No Change
Findings ID: GEN007660 Rule ID: SV-63447r1_rule Severity: medium CCI: CCI-001551

Discussion

Bluetooth is a Personal Area Network (PAN) technology. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the kernel to dynamically load a protocol handler by opening a socket using the protocol.System Administrator

Checks

Verify the Bluetooth protocol handler is prevented from dynamic loading.
# grep 'install bluetooth /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no result is returned, this is a finding.

Fix

Prevent the Bluetooth protocol handler for dynamic loading.
# echo "install bluetooth /bin/true" >> /etc/modprobe.conf
V-22545 No Change
Findings ID: GEN007780 Rule ID: SV-63423r1_rule Severity: medium CCI: CCI-001551

Discussion

6to4 is an IPv6 transition mechanism involving tunneling IPv6 packets encapsulated in IPv4 packets on an ad-hoc basis. This is not a preferred transition strategy and increases the attack surface of the system.System Administrator

Checks

Check the system for any active 6to4 tunnels without specific remote addresses.

# ip tun list | grep "remote any" | grep "ipv6/ip"

If any results are returned the "tunnel" is the first field.

If any results are returned, this is a finding.

Fix

Disable the active 6to4 tunnel.

# ip link set <tunnel> down

Add this command to a startup script, or remove the configuration creating the tunnel.
V-22546 No Change
Findings ID: GEN007800 Rule ID: SV-63417r1_rule Severity: medium CCI: CCI-001551

Discussion

Teredo is an IPv6 transition mechanism involving tunneling IPv6 packets encapsulated in IPv4 packets. Unauthorized tunneling may circumvent network security.System Administrator

Checks

Verify the Miredo service is not running.
# ps ax | grep miredo | grep -v grep
If the miredo process is running, this is a finding.

Fix

Edit startup scripts to prevent the service from running on startup.
V-22547 No Change
Findings ID: GEN007820 Rule ID: SV-63413r1_rule Severity: medium CCI: CCI-001551

Discussion

IP tunneling mechanisms can be used to bypass network filtering.System Administrator

Checks

Check for any IP tunnels.
# ip tun list
# ip -6 tun list
If any tunnels are listed, this is a finding.

Fix

Remove the tunnels.
# ip tun del <tunnel>
Edit system startup scripts to prevent tunnel creation on startup.
V-22548 No Change
Findings ID: GEN007840 Rule ID: SV-63411r1_rule Severity: medium CCI: CCI-000366

Discussion

DHCP allows for the unauthenticated configuration of network parameters on the system by exchanging information with a DHCP server.System Administrator

Checks

Verify no interface is configured to use DHCP.

# grep -i bootproto=dhcp /etc/sysconfig/network-scripts/ifcfg-*

If any configuration is found, this is a finding.

Fix

Edit the "/etc/sysconfig/network-scripts/ifcfg-*" file(s) and change the "bootproto" setting to "static".
V-22549 No Change
Findings ID: GEN007850 Rule ID: SV-63409r1_rule Severity: medium CCI: CCI-000366

Discussion

Dynamic DNS updates transmit unencrypted information about a system including its name and address and should not be used unless needed.System Administrator

Checks

If the "dhclient" package is not installed, this is not applicable.

Verify the DHCP client is configured to not send dynamic DNS updates.

Procedure:
# grep do-forward-updates /etc/dhclient.conf

If the file is not present, does not contain this configuration, or has the setting set to "true", this is a finding.

Fix

Edit or add the "/etc/dhclient.conf" file and add or edit the "do-forward-updates" setting to false.

Procedure:
# echo "do-forward-updates false;" >> /etc/dhclient.conf
V-22550 No Change
Findings ID: GEN007860 Rule ID: SV-63401r1_rule Severity: medium CCI: CCI-001551

Discussion

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.System Administrator

Checks

Verify the system is configured to ignore IPv6 ICMP redirect messages.
# cat /proc/sys/net/ipv6/conf/all/accept_redirects

If the /proc/sys/net/ipv6/conf/all/accept_redirects entry does not exist because of compliance with GEN007720, this is not a finding.

If the returned value is not "0", this is a finding.

Fix

Configure the system to ignore IPv6 ICMP redirect messages.
Edit "/etc/sysctl.conf" and add a settings for "net.ipv6.conf.default.accept_redirects=0" and "net.ipv6.conf.all.accept_redirects=0".
Restart the system for the setting to take effect.
V-22553 No Change
Findings ID: GEN007920 Rule ID: SV-63393r1_rule Severity: medium CCI: CCI-001551

Discussion

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router. System Administrator

Checks

Determine if the system is configured to forward IPv6 source-routed packets.

Procedure:
# egrep "net.ipv6.conf.*forwarding" /etc/sysctl.conf
If there are no entries found or the value of the entries is not = "0", this is a finding.

Fix

Configure the system to not forward IPv6 source-routed packets.

Procedure:
Edit the /etc/sysctl.conf file to include:
net.ipv6.conf.all.forwarding = 0
net.ipv6.conf.default.forwarding = 0

Reload the kernel parameters:
# sysctl -p
V-22555 No Change
Findings ID: GEN007980 Rule ID: SV-63369r3_rule Severity: medium CCI: CCI-001453

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires protection.System Administrator

Checks

To check to see if the system is an LDAP server, verify LDAP is running on the system:

# ps -ef | grep ldap

Find out which LDAP is used (if not determined via the command above).

# rpm -qa | grep ldap

If using nssldap:

# grep base /etc/ldap.conf

Check to see if the base is set to something besides the default of "dc=example,dc=com".

If using openldap:

# grep suffix /etc/openldap/slapd.conf

Check whether the system is an LDAP client:

# grep server /etc/ldap.conf
# grep server /etc/openldap/ldap.conf

Check whether the server option has an address other than the loopback, then check the nsswitch.conf file.

# grep ldap /etc/nsswitch.conf

Look for the following three lines:

passwd: files ldap
shadow: files ldap
group: files ldap

If all three files are not configured to look for an LDAP source, then the system is not using LDAP for authentication.

If the system is not using LDAP for authentication, this is not applicable.

Check if NSS LDAP is using TLS.

# grep '^ssl start_tls' /etc/ldap.conf

If no lines are returned, this is a finding.

Check if NSS LDAP TLS is using only FIPS 140-2 approved cryptographic algorithms.

# grep '^tls_ciphers' /etc/ldap.conf

If the line is not present or contains ciphers not approved by FIPS 140-2, this is a finding.

FIPS-approved ciphers include 3DES and AES. FIPS-approved hashes include the SHA hash family.

Fix

Edit "/etc/ldap.conf" and add a "ssl start_tls" and "tls_ciphers" options with only FIPS 140-2 approved ciphers.
V-22556 No Change
Findings ID: GEN008000 Rule ID: SV-63365r1_rule Severity: medium CCI: CCI-000185

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires authentication.System Administrator

Checks

Verify the source of the LDAP certificates
Check if the system is using NSS LDAP.
# grep -v '^#' /etc/nsswitch.conf | grep ldap
If no lines are returned, this vulnerability is not applicable.

Verify with the SA that the system is connected to the GIG.
If the system part of a standalone network which is not connected to the GIG this vulnerability is not applicable.

Verify a certificate is used for client authentication to the server.
# grep -i '^tls_cert' /etc/ldap.conf
If no line is found, this is a finding.

List the certificate issuer.
# openssl x509 -text -in <cert>
If the certificate is not issued by DoD PKI or a DoD-approved external PKI, this is a finding.

Fix

Edit "/etc/ldap.conf" and add or edit the 'tls_cert' setting to reference a file containing a client certificate issued by DoD PKI or a DoD-approved external PKI.
V-22557 No Change
Findings ID: GEN008020 Rule ID: SV-63361r1_rule Severity: medium CCI: CCI-000185

Discussion

The NSS LDAP service provides user mappings which are a vital component of system security. Communication between an LDAP server and a host using LDAP for NSS require authentication.System Administrator

Checks

Check if the system is using NSS LDAP.
# grep -v '^#' /etc/nsswitch.conf | grep ldap
If no lines are returned, this vulnerability is not applicable.

Verify a server certificate is required and verified by the NSS LDAP configuration.
# grep -i '^tls_checkpeer' /etc/ldap.conf
If no line is returned, or the value is not "yes", this is a finding.

Fix

Edit "/etc/ldap.conf" and add or set the "tls_checkpeer" setting to "yes".
V-22558 No Change
Findings ID: GEN008040 Rule ID: SV-63357r1_rule Severity: medium CCI: CCI-000185

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires authentication.System Administrator

Checks

Check if the system is using NSS LDAP.

# grep -v '^#' /etc/nsswitch.conf | grep ldap

If no lines are returned, this vulnerability is not applicable.

Verify the NSS LDAP client is configured to check certificates against a certificate revocation list.

# grep -i '^tls_crlcheck' /etc/ldap.conf

If the setting does not exist, or the value is not "all", this is a finding.

Fix

Edit "/etc/ldap.conf" and add or set the "tls_crlcheck" setting to "all".
V-22559 No Change
Findings ID: GEN008060 Rule ID: SV-63349r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/ldap.conf
If the mode of the file is more permissive than 0644, this is a finding.

Fix

Change the permissions of the file.
# chmod 0644 /etc/ldap.conf
V-22560 No Change
Findings ID: GEN008080 Rule ID: SV-63321r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Check the ownership of the file.
# ls -lL /etc/ldap.conf
If the file is not owned by root, this is a finding.

Fix

Change the owner of the file.

# chown root /etc/ldap.conf
V-22561 No Change
Findings ID: GEN008100 Rule ID: SV-63317r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Check the group ownership of the file.

Procedure:
# ls -lL /etc/ldap.conf

If the file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group owner of the file to root, bin, sys, or system.

Procedure:
# chgrp root /etc/ldap.conf
V-22562 No Change
Findings ID: GEN008120 Rule ID: SV-63315r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/ldap.conf
If the mode includes a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the "/etc/ldap.conf" file.
# setfacl --remove-all /etc/ldap.conf
V-22563 No Change
Findings ID: GEN008140 Rule ID: SV-63303r3_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine if LDAP is used for account information on the system.

To check to see if the system is an LDAP server, verify LDAP is running on the system:

# ps -ef | grep ldap

Find out which LDAP is used (if not determined via the command above).

# rpm -qa | grep ldap

If using nssldap:

# grep base /etc/ldap.conf

Check to see if the base is set to something besides the default of "dc=example,dc=com".

If using openldap:

# grep suffix /etc/openldap/slapd.conf

Check whether the system is an LDAP client:

# grep server /etc/ldap.conf
# grep server /etc/openldap/ldap.conf

Check whether the server option has an address other than the loopback, then check the nsswitch.conf file.

# grep ldap /etc/nsswitch.conf

Look for the following three lines:

passwd: files ldap
shadow: files ldap
group: files ldap

If no uncommented reference to "ldap" is identified, LDAP is not used for account information on the system and this is not applicable.

Determine the certificate authority file and/or directory.
# grep -i '^tls_cacert' /etc/ldap.conf

For each file or directory returned, check the ownership.
# ls -lLd <certpath>

If the owner of any file or directory is not root, this is a finding.

Fix

Change the ownership of the file or directory.

# chown root <certpath>
V-22564 No Change
Findings ID: GEN008160 Rule ID: SV-63291r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the certificate authority file and/or directory.

# grep -i '^tls_cacert' /etc/ldap.conf

For each file or directory returned, check the group ownership.

# ls -lLd <certpath>

If the group-owner of any file or directory is not root, bin, sys, or system, this is a finding.

Fix

Change the group ownership of the file or directory.

# chgrp root <certpath>
V-22565 No Change
Findings ID: GEN008180 Rule ID: SV-63289r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the certificate authority file and/or directory.

Procedure:
# grep -i '^tls_cacert' /etc/ldap.conf
For each file or directory returned, check the permissions.

Procedure:
# ls -lLd <certpath>

If the mode of the file is more permissive than 0644 (or 0755 for directories), this is a finding.

Fix

Change the mode of the file or directory.

File Procedure:
# chmod 0644 <certpath>

Directory Procedure:
# chmod 0755 <certpath>
V-22566 No Change
Findings ID: GEN008200 Rule ID: SV-63287r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the certificate authority file and/or directory.

# grep -i '^tls_cacert' /etc/ldap.conf

For each file or directory returned, check the permissions.

# ls -lLd <certpath>

If the mode of the file or directory contains a '+', an extended ACL is present.

If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the certificate file.

Procedure:
For each certificate file found remove all extended permissions

# setfacl --remove-all <certpath>
V-22567 No Change
Findings ID: GEN008220 Rule ID: SV-63257r1_rule Severity: medium CCI: CCI-000225

Discussion

The NSS LDAP service provides user mappings which are a vital component of system security. Its configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the certificate file.
# grep -i '^tls_cert' /etc/ldap.conf
Check the ownership.
# ls -lL <certpath>
If the owner of the file is not root, this is a finding.

Fix

Change the ownership of the file.
# chown root <certpath>
V-22568 No Change
Findings ID: GEN008240 Rule ID: SV-63253r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the certificate file.
Procedure:
# grep -i '^tls_cert' /etc/ldap.conf

Check the group ownership.
Procedure:
# ls -lL <certpath>

If the group owner of the file is not root, bin, sys, or system, this is a finding.

Fix

Change the group ownership of the file.

Procedure:
# chgrp root <certpath>
V-22569 No Change
Findings ID: GEN008260 Rule ID: SV-63249r2_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Identify the LDAP TLS Certificate file:

# cat <ldap_config_file> | grep -i “^tls”

TLSCACertificatePath <path>
TLSCACertificateFile <filename>
TLSCertificateFile <filename>

For each TLSCACertificateFile and TLSCertificateFile defined in the configuration file, verify the file permissions:

# ls -la <tls_certificate_file>

If the mode of the file is more permissive than 0644, this is a finding.

Fix

Change the mode of the file.
# chmod 0644 <certpath>
V-22570 No Change
Findings ID: GEN008280 Rule ID: SV-63245r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the certificate file.

# grep -i '^tls_cert' /etc/ldap.conf

Check the permissions.
# ls -lL <certpath>

If the mode of the file contains a '+', an extended ACL is present. This is a finding.

Fix

Remove the extended ACL from the certificate file.

Procedure:
For each certificate file found remove all extended permissions.

# setfacl --remove-all <certpath>
V-22571 No Change
Findings ID: GEN008300 Rule ID: SV-63243r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the key file.

# grep -i '^tls_key' /etc/ldap.conf

Check the ownership.
# ls -lL <keypath>

If the owner of the file is not root, this is a finding.

Fix

Change the ownership of the file.
# chown root <keypath>
V-22572 No Change
Findings ID: GEN008320 Rule ID: SV-63235r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the key file.

# grep -i '^tls_key' /etc/ldap.conf

Check the group ownership.
# ls -lL <keypath>

If the file is not group owned by root, bin, or sys, this is a finding.

Fix

Change the group ownership of the file.

# chgrp root <keypath>
V-22573 No Change
Findings ID: GEN008340 Rule ID: SV-63233r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.

Note: Depending on the particular implementation, group and other read permission may be necessary for unprivileged users to successfully resolve account information using LDAP. This will still be a finding, as these permissions provide users with access to system authenticators.System Administrator

Checks

Determine the key file.
# grep -i '^tls_key' /etc/ldap.conf
Check the permissions.
# ls -lL <keypath>
If the mode of the file is more permissive than 0600, this is a finding.

Fix

Change the mode of the file.
# chmod 0600 <keypath>
V-22574 No Change
Findings ID: GEN008360 Rule ID: SV-63213r1_rule Severity: medium CCI: CCI-000225

Discussion

LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.System Administrator

Checks

Determine the key file.
# grep -i '^tls_key' /etc/ldap.conf
Check the permissions.
# ls -lL <keypath>
If the permissions of the file contains a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the key file.

Procedure:
For each key file found remove all extended permissions.

# setfacl --remove-all <keypath>
V-22576 No Change
Findings ID: GEN008420 Rule ID: SV-63197r1_rule Severity: low CCI: CCI-000366

Discussion

Successful exploitation of buffer overflow vulnerabilities relies in some measure to having a predictable address structure of the executing program. Address randomization techniques reduce the probability of a successful exploit.System Administrator

Checks

Check that the "kernel.randomize_va_space" kernel parameter is set to "2" in /etc/sysctl.conf.

Procedure:

# grep ^kernel\.randomize_va_space /etc/sysctl.conf | awk -F= '{ print $2 }'

If there is no value returned or if a value is returned that is not "2", this is a finding.

Fix

Edit (or add if necessary) the entry in /etc/sysctl.conf for the "kernel.randomize_va_space" kernel parameter. Ensure this parameter is set to "2" as in:

kernel.randomize_va_space = 2

If this was not already the default, reboot the system for the change to take effect.
V-22577 No Change
Findings ID: GEN008440 Rule ID: SV-63193r1_rule Severity: low CCI: CCI-000366

Discussion

Automated file system mounting tools may provide unprivileged users with the ability to access local media and network shares. If this access is not necessary for the system's operation, it must be disabled to reduce the risk of unauthorized access to these resources.System Administrator

Checks

If the autofs service is needed, this vulnerability is not applicable.
Check if the autofs service is running.
# service autofs status
If the service is running, this is a finding.

Fix

Stop and disable the autofs service.
# service autofs stop
# chkconfig autofs off
V-22578 No Change
Findings ID: GEN008460 Rule ID: SV-63189r1_rule Severity: low CCI: CCI-000366

Discussion

USB is a common computer peripheral interface. USB devices may include storage devices with the potential to install malicious software on a system or exfiltrate data.trueSystem Administrator

Checks

If the system needs USB, this vulnerability is not applicable.
Check if the directory "/proc/bus/usb" exists. If so, this is a finding.

Fix

Edit the grub bootloader file "/boot/grub/grub.conf" or "/boot/grub/menu.lst" by appending the "nousb" parameter to the kernel boot line.
V-22579 No Change
Findings ID: GEN008480 Rule ID: SV-63179r1_rule Severity: low CCI: CCI-000366

Discussion

USB is a common computer peripheral interface. USB devices may include storage devices with the potential to install malicious software on a system or exfiltrate datatrueSystem Administrator

Checks

If the system needs USB storage, this vulnerability is not applicable.
Check if usb-storage is prevented from loading.
# grep 'install usb-storage /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no results are returned, this is a finding.

Fix

Prevent the usb-storage module from loading.
# echo 'install usb-storage /bin/true' >> /etc/modprobe.conf
V-22580 No Change
Findings ID: GEN008500 Rule ID: SV-63173r1_rule Severity: low CCI: CCI-000366

Discussion

Firewire is a common computer peripheral interface. Firewire devices may include storage devices with the potential to install malicious software on a system or exfiltrate data.trueSystem Administrator

Checks

If the system needs IEEE 1394 (Firewire), this is not applicable.
Check if the Firewire module is not disabled.
# grep 'install ieee1394 /bin/true' /etc/modprobe.conf /etc/modprobe.d/*
If no results are returned, this is a finding.

Fix

Prevent the system from loading the Firewire module.
# echo 'install ieee1394 /bin/true' >> /etc/modprobe.conf
V-22582 No Change
Findings ID: GEN008520 Rule ID: SV-63149r1_rule Severity: medium CCI: CCI-001118

Discussion

A local firewall protects the system from exposing unnecessary or undocumented network services to the local enclave. If a system within the enclave is compromised, firewall protection on an individual system continues to protect it from attack.System Administrator

Checks

Determine if the system is using a local firewall.
# chkconfig --list iptables
If the service is not "on" in the standard runlevel (ordinarily 3 or 5), this is a finding.

Fix

Enable the system's local firewall.
# chkconfig iptables on
# service iptables start
V-22583 No Change
Findings ID: GEN008540 Rule ID: SV-63141r1_rule Severity: medium CCI: CCI-001109

Discussion

A local firewall protects the system from exposing unnecessary or undocumented network services to the local enclave. If a system within the enclave is compromised, firewall protection on an individual system continues to protect it from attack.System Administrator

Checks

Check the firewall rules for a default deny rule.

# iptables --list

Example of a rule meeting this criteria:
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited

A rule using DROP is also acceptable. The default rule should be the last rule of a table and match all traffic.

If there is no default deny rule, this is a finding.

Fix

Edit "/etc/sysconfig/iptables" and add a default deny rule.

An example of a default deny rule:
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited

Restart the iptable service.
# service iptables restart
V-22584 No Change
Findings ID: GEN000000-LNX00800 Rule ID: SV-63085r1_rule Severity: low CCI: CCI-000366

Discussion

Linux Security Modules such as SELinux and AppArmor can be used to provide protection from software exploits by explicitly defining the privileges permitted to each software package.System Administrator

Checks

Check if SELinux is enabled with at least a "targeted" policy.

# grep ^SELINUX /etc/sysconfig/selinux

If the SELINUX option is not set to "enforcing", this is a finding.
If the SELINUXTYPE option is not set to "targeted" or "strict", this is a finding.

If the use of the system is incompatible with the confines of SELinux this rule may be waived.

Fix

Enable one of the SELinux policies.
Edit /etc/sysconfig/selinux and set the value of the SELINUX option to "enforcing" and SELINUXTYPE to "targeted" or "strict".
Restart the system.
V-22585 No Change
Findings ID: GEN008740 Rule ID: SV-63091r1_rule Severity: medium CCI: CCI-000225

Discussion

File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. If extended ACLs are present on the system's boot loader configuration file(s), these files may be vulnerable to unauthorized access or modification, which could compromise the system's boot process.System Administrator

Checks

Check the permissions of the file.

# ls -lL /boot/grub/grub.conf

If the permissions of the file or directory contains a '+', an extended ACL is present. This is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /boot/grub/grub.conf
V-22586 No Change
Findings ID: GEN008760 Rule ID: SV-63089r1_rule Severity: medium CCI: CCI-000225

Discussion

The system's boot loader configuration files are critical to the integrity of the system and must be protected. Unauthorized modification of these files resulting from improper ownership could compromise the system's boot loader configuration.System Administrator

Checks

Check the ownership of the file.
# ls -lLd /boot/grub/grub.conf
If the owner of the file is not root, this is a finding.

Fix

Change the ownership of the file.
# chown root /boot/grub/grub.conf
V-22587 No Change
Findings ID: GEN008780 Rule ID: SV-63069r1_rule Severity: medium CCI: CCI-000225

Discussion

The system's boot loader configuration files are critical to the integrity of the system and must be protected. Unauthorized modifications resulting from improper group ownership may compromise the boot loader configuration.System Administrator

Checks

Check the group ownership of the file.
# ls -lLd /boot/grub/grub.conf
If the group-owner of the file is not root, bin, sys, or system this is a finding.

Fix

Change the group ownership of the file.
# chgrp root /boot/grub/grub.conf
V-22588 No Change
Findings ID: GEN008800 Rule ID: SV-63027r2_rule Severity: low CCI: CCI-000351

Discussion

To prevent the installation of software from unauthorized sources, the system package management tool must use cryptographic algorithms to verify the packages are authentic.System Administrator

Checks

Verify YUM signature validation is not disabled.
# grep gpgcheck /etc/yum.conf /etc/yum.repos.d/*

If no results are returned, or the returned “gpgcheck” settings are not equal to “1”, this is a finding.

Fix

Edit the YUM configuration containing "gpgcheck=0" and set the value to "1".
V-22589 No Change
Findings ID: GEN008820 Rule ID: SV-63025r1_rule Severity: low CCI: CCI-001233

Discussion

System package management tools can obtain a list of updates and patches from a package repository and make this information available to the SA for review and action. Using a package repository outside of the organization's control presents a risk of malicious packages being introduced.System Administrator

Checks

Verify the YUM service is enabled.
# service yum-updatesd status
If the service is enabled, this is a finding.

Fix

Disable the yum service.
# chkconfig yum-updatesd off ; service yum-updatesd stop
V-22595 No Change
Findings ID: GEN000000-LNX00450 Rule ID: SV-62909r1_rule Severity: medium CCI: CCI-000225

Discussion

If the access permissions are more permissive than 0640, system security could be compromised.System Administrator

Checks

Check the permissions of the file.
# ls -lL /etc/security/access.conf
If the permissions of the file or directory contain a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/security/access.conf
V-22596 No Change
Findings ID: GEN000000-LNX00530 Rule ID: SV-62983r1_rule Severity: medium CCI: CCI-000225

Discussion

The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security.System Administrator

Checks

Check the permissions of the file.

# ls -lL /etc/sysctl.conf

If the permissions of the file or directory contain a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix

Remove the extended ACL from the file.
# setfacl --remove-all /etc/sysctl.conf
V-22598 No Change
Findings ID: GEN000000-LNX00720 Rule ID: SV-63081r1_rule Severity: low CCI: CCI-000366

Discussion

If auditing is enabled late in the boot process, the actions of startup scripts may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created.System Administrator

Checks

Check for the audit=1 kernel parameter.
# grep 'audit=1' /proc/cmdline
If no results are returned, this is a finding.

Fix

Edit the grub bootloader file /boot/grub/grub.conf or /boot/grub/menu.lst by appending the "audit=1" parameter to the kernel boot line.
Reboot the system for the change to take effect.
V-22665 No Change
Findings ID: GEN005590 Rule ID: SV-64111r1_rule Severity: medium CCI: CCI-000366

Discussion

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network.System Administrator

Checks

Check for any running routing protocol daemons. If the system is a VM host and acts as a router solely for the benefits of its client systems, then this rule is not applicable.

# chkconfig --list |grep :on|egrep '(ospf|route|bgp|zebra|quagga)'

If any routing protocol daemons are listed, this is a finding.

Fix

Disable any routing protocol daemons.
V-22702 No Change
Findings ID: GEN002690 Rule ID: SV-63873r1_rule Severity: medium CCI: CCI-000162

Discussion

Sensitive system and user information could provide a malicious user with enough information to penetrate further into the system.System Administrator

Checks

Check the group ownership of the audit logs.

Procedure:
# grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %G:%n

If any audit log file is not group-owned by root, bin, sys, or system, this is a finding.

Fix

Change the group ownership of the audit log file(s).

Procedure:
# chgrp root <audit log file>
V-23732 No Change
Findings ID: GEN000410 Rule ID: SV-63359r1_rule Severity: medium CCI: CCI-000048

Discussion

Failure to display the logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.

Note: SFTP and FTPS are encrypted alternatives to FTP to be used in place of FTP. SFTP is implemented by the SSH service and uses its banner configuration.System Administrator

Checks

FTP to the system.
# ftp localhost
Check for either of the following login banners based on the character limitations imposed by the system. An exact match is required. If one of these banners is not displayed, this is a finding. If the system does not run the FTP service, this is not applicable.

DoD Login Banners:

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.

Fix

Provide the proper text for the DoD banner to be presented by the FTP server to the user.

For vsftp:
Examine the /etc/vsftp.conf file for the "banner_file" entry. (i.e., banner_file = /etc/banner/vsftp)

For gssftp:
Examine the /etc/xinetd.d/gssftp file for the "banner" entry. (i.e., banner = /etc/banner/gssftp)

For both:
Add the banner entry if one is not found.

Modify or create the referenced banner file to contain one of the following DoD login banners (based on the character limitations imposed by the system).

DoD Login Banners:

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.
V-23736 No Change
Findings ID: GEN003621 Rule ID: SV-64217r1_rule Severity: low CCI: CCI-001208

Discussion

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.System Administrator

Checks

Determine if the /var path is a separate filesystem.
# grep /var /etc/fstab
If no result is returned, /var is not on a separate filesystem this is a finding.

Fix

Migrate the /var path onto a separate file system.
V-23738 No Change
Findings ID: GEN003623 Rule ID: SV-64219r1_rule Severity: low CCI: CCI-001208

Discussion

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.System Administrator

Checks

Determine if the /var/log/audit path is a separate filesystem.
# grep /var/log/audit /etc/fstab
If no result is returned, /var/log/audit is not on a separate filesystem this is a finding.

Fix

Migrate the /var/log/audit path onto a separate filesystem.
V-23739 No Change
Findings ID: GEN003624 Rule ID: SV-64221r1_rule Severity: low CCI: CCI-001208

Discussion

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.System Administrator

Checks

Determine if the /tmp path is a separate filesystem.
# egrep "[\t ]/tmp[\t ]" /etc/fstab
If no result is returned, /tmp is not on a separate filesystem this is a finding.

Fix

Migrate the /tmp path onto a separate file system.
V-23741 No Change
Findings ID: GEN003601 Rule ID: SV-64457r1_rule Severity: medium CCI: CCI-000366

Discussion

To provide some mitigation to TCP Denial of Service attacks, the TCP backlog queue sizes must be set to at least 1280 or in accordance with product-specific guidelines.System Administrator

Checks

# cat /proc/sys/net/ipv4/tcp_max_syn_backlog
If the result is not 1280 or greater, this is a finding.

Fix

Edit /etc/sysctl.conf and add a setting for "net.ipv4.tcp_max_syn_backlog=1280".

Procedure:
# sysctl -p
V-23952 No Change
Findings ID: GEN004710 Rule ID: SV-62879r2_rule Severity: medium CCI: CCI-001305

Discussion

If unrestricted mail relaying is permitted, unauthorized senders could use this host as a mail relay for the purpose of sending SPAM or other unauthorized activity.System Administrator

Checks

If the system uses sendmail examine the configuration files.

Determine if sendmail only binds to loopback addresses by examining the "DaemonPortOptions" configuration options.

Procedure:
# grep -i "O DaemonPortOptions" /etc/mail/sendmail.cf

If there are uncommented DaemonPortOptions lines, and all such lines specify system loopback addresses, this is not a finding.

Otherwise, determine if sendmail is configured to allow open relay operation.

Procedure:
# grep -i promiscuous_relay /etc/mail/sendmail.mc

If the promiscuous relay feature is enabled, this is a finding.

If the system uses Postfix, locate the main.cf file.

Procedure:
# find / -name main.cf

Determine if Postfix only binds to loopback addresses by examining the "inet_interfaces" line.

Procedure:
# grep inet_interfaces </path/to/main.cf>

If "inet_interfaces" is set to "loopback-only" or contains only loopback addresses such as 127.0.0.1 and [::1], Postfix is not listening on external network interfaces, and this is not a finding.

Otherwise, determine if Postfix is configured to restrict clients permitted to relay mail by examining the "smtpd_client_restrictions" line.

Procedure:
# grep smtpd_client_restrictions </path/to/main.cf>

If the "smtpd_client_restrictions" line is missing, or does not contain "reject", this is a finding.

If the line contains "permit" before "reject", this is a finding.

If the system is using other SMTP software, consult the software's documentation for procedures to verify mail relaying is restricted.

Fix

If the system uses sendmail, edit the sendmail.mc file and remove the "promiscuous_relay" configuration.

Rebuild the sendmail.cf file from the modified sendmail.mc and restart the service.

If the system does not need to receive mail from external hosts, add one or more DaemonPortOptions lines referencing system loopback addresses (such as "O DaemonPortOptions=Addr=127.0.0.1,Port=smtp,Name=MTA") and remove lines containing non-loopback addresses.

Restart the service.

If the system uses Postfix, edit the main.cf file and add or edit the "smtpd_client_restrictions" line to have contents "permit_mynetworks, reject" or a similarly restrictive rule.

If the system does not need to receive mail from external hosts, add or edit the "inet_interfaces" line to have contents "loopback-only" or a set of loopback addresses for the system.

Restart the service.

If the system is using other SMTP software, consult the software's documentation for procedures to restrict mail relaying.
V-23953 No Change
Findings ID: GEN007960 Rule ID: SV-63379r1_rule Severity: medium CCI: CCI-000305

Discussion

The 'ldd' command provides a list of dependent libraries needed by a given binary, which is useful for troubleshooting software. Instead of parsing the binary file, some 'ldd' implementations invoke the program with a special environment variable set, which causes the system dynamic linker to display the list of libraries. Specially crafted binaries can specify an alternate dynamic linker which may cause a program to be executed instead of examined. If the program is from an untrusted source, such as in a user home directory, or a file suspected of involvement in a system compromise, unauthorized software may be executed with the rights of the user running 'ldd'.

Some 'ldd' implementations include protections that prevent the execution of untrusted files. Recent glibc RPMs delivered by this operating system also protect against the execution of untrusted files. If such protections exist, this requirement is not applicable.

An acceptable method of disabling 'ldd' is changing its mode to 0000. The SA may conduct troubleshooting by temporarily changing the mode to allow execution and running the 'ldd' command as an unprivileged user upon trusted system binaries.System Administrator

Checks

Check the system for the 'ldd' binary.

Procedure:
# ls -lL /usr/bin/ldd

If the 'ldd' binary has any executable permissions bits set, this is a finding.

Fix

Remove the execute permissions from the 'ldd' executable.

Procedure:
# chmod a-x /usr/bin/ldd
V-23972 No Change
Findings ID: GEN007950 Rule ID: SV-63385r1_rule Severity: medium CCI: CCI-000366

Discussion

Responding to broadcast ICMP echo requests facilitates network mapping and provides a vector for amplification attacks.System Administrator

Checks

Check for an iptables rule that drops inbound IPv6 ICMP ECHO_REQUESTs sent to the all-hosts multicast address.

Procedure:
# less /etc/sysconfig/ip6tables

Check for a rule in, or referenced by, the INPUT chain such as:
-A INPUT -p icmpv6 -d ff02::1 --icmpv6-type 128 -j DROP

If such a rule does not exist, this is a finding.

Fix

Add an iptables rule that drops inbound IPv6 ICMP ECHO_REQUESTs sent to the all-hosts multicast address.

Edit /etc/sysconfig/ip6tables and add a rule in, or referenced by, the INPUT chain such as:
-A INPUT -p icmpv6 -d ff02::1 --icmpv6-type 128 -j DROP

Reload the iptables rules.
Procedure:
# service ip6tables restart
V-24331 No Change
Findings ID: GEN000402 Rule ID: SV-63351r1_rule Severity: medium CCI: CCI-000048

Discussion

Failure to display the logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.

This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients.System Administrator

Checks

Access the graphical desktop environment(s) provided by the system and attempt to log in. Check for either of the following login banners based on the character limitations imposed by the system. An exact match is required. If one of these banners is not displayed, this is a finding.

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.

Fix

Configure the system to display one of the DoD login banners prior to, or as part of, the graphical desktop environment login process.

Procedure:
Modify /usr/share/gdm/themes/RHEL/RHEL.xml by adding the following xml after the first two "pixmap" entries.

<item type="rect" id="custom-dod-banner">
<pos anchor="nw" x="20%" y="10" width="80%" height="100%"/>
<box>
<item type="label">
<normal font="Sans Bold 9" color="#ffffff"/>
<text>
Insert the "approved text" here based on the character limitations imposed by the system.
</text>
</item>
</box>
</item>


Approved text:

DoD Login Banners:

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.
V-24347 No Change
Findings ID: GEN009120 Rule ID: SV-63005r2_rule Severity: medium CCI: CCI-000768

Discussion

In accordance with CTO 07-015 PKI authentication is required. This provides stronger, two-factor authentication than using a username/password.

NOTE: The following are exempt from this, however, they must meet all password requirements and must be documented with the IAO:

- Stand-alone systems.
- Application Accounts.
- Students or unpaid employees (such as, interns) who are not eligible to receive or not in receipt of a CAC, PIV, or ALT.
- Warfighters and support personnel located at operational tactical locations conducting wartime operations that are not collocated with RAPIDS workstations to issue CAC; are not eligible for CAC or do not have the capability to use ALT.
- Test systems that have an Interim Approval to Test (IATT) and provide protection via separate VPN, firewall, or security measures preventing access to network and system components from outside the protection boundary documented in the IATT.System Administrator

Checks

Consult vendor documentation to determine if the system is capable of CAC authentication. If it is not, this is not applicable.

Interview the SA to determine if all accounts not exempted by policy are using CAC authentication. If non-exempt accounts are not using CAC authentication, this is a finding.

Fix

Consult vendor documentation to determine the procedures necessary for configuring CAC authentication. Configure all accounts required by policy to use CAC authentication.
V-24357 No Change
Findings ID: GEN002870 Rule ID: SV-64419r2_rule Severity: low CCI: CCI-000136

Discussion

System/Audit records contain evidence that can be used in the investigation of compromised systems. To prevent this evidence from compromise, it must be sent to a separate system continuously. Methods for sending audit records include, but are not limited to, system audit tools used to send logs directly to another host or through the system's syslog service to another host.System AdministratorECTB-1

Checks

Verify the system is configured to forward all audit records to a remote server.

If the system is not configured to provide this function, this is a finding.

Procedure:

Ensure the audit option for the kernel is enabled.

# grep "audit" /boot/grub/grub.conf | grep -v "^#"

If the kernel does not have the "audit=1" option specified, this is a finding.

Ensure the kernel auditing is active.

# grep "active" /etc/audisp/plugins.d/syslog.conf | grep -v "^#"

If the "active" setting is either missing or not set to "yes", this is a finding.

Ensure all audit records are forwarded to a remote server.

# grep "\*.\*" /etc/syslog.conf |grep "@" | grep -v "^#" (for syslog)

or:

# grep "\*.\*" /etc/rsyslog.conf | grep "@" | grep -v "^#" (for rsyslog)

If neither of these lines exist, it is a finding.

Fix

Configure the system to send audit records to a remote server.

Procedure:

These instructions assume a known remote audit server is available to this system.

Modify /etc/syslog.conf or /etc/rsyslog.conf to contain a line sending all audit records to a remote audit server.

The server is specified by placing an "@" before the DNS name or IP address in the line.

*.* @<remote audit server>

Edit the "active" line in /etc/audisp/plugins.d/syslog.conf so it shows "active = yes".

Restart audit and syslog:

# service auditd restart
# service syslog restart

Or:

# service rsyslog restart
V-24384 No Change
Findings ID: GEN008050 Rule ID: SV-63355r3_rule Severity: medium CCI: CCI-000196

Discussion

The authentication of automated LDAP connections between systems must not use passwords since more secure methods are available, such as PKI and Kerberos. Additionally, the storage of unencrypted passwords on the system is not permitted.System Administrator

Checks

Verify LDAP is running on the system. To check to see if the system is an LDAP server run:

# ps -ef | grep ldap

Find out which LDAP is used (if not determined via the command above).

# rpm -qa | grep ldap

If using nssldap:

# grep base /etc/ldap.conf

Check to see if the base is set to something besides the default of "dc=example,dc=com".

If using openldap:

# grep suffix /etc/openldap/slapd.conf

Check whether the system is an LDAP client:

# grep server /etc/ldap.conf
# grep server /etc/openldap/ldap.conf

Check whether the server option has an address other than the loopback, then check the nsswitch.conf file:

# grep ldap /etc/nsswitch.conf

Look for the following three lines:

passwd: files ldap
shadow: files ldap
group: files ldap

If all three files are not configured to look for an LDAP source, then the system is not using LDAP for authentication.

If the system is not using LDAP for authentication, this is not applicable.

Check for the "bindpw" option being used in the "/etc/ldap.conf" file.

# grep bindpw /etc/ldap.conf

If an uncommented "bindpw" option is returned, then a clear text password is in the file, and this is a finding.

Fix

Edit the "/etc/ldap.conf" file to use anonymous binding by removing the "bindpw" option.
V-24386 No Change
Findings ID: GEN003850 Rule ID: SV-64021r1_rule Severity: high CCI: CCI-000197

Discussion

The telnet daemon provides a typically unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to log on using this service, the privileged user password could be compromised.GEN003850-OL5If 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, and this is not a finding.System Administrator

Checks

The telnet service included in the operating system is a part of krb5-workstation. There are two versions of telnetd server provided. The xinetd.d file ekrb5-telnet allows only connections authenticated through Kerberos. The xinetd.d krb5-telnet allows normal telnet connections as well as kerberized connections. Both are set to "disable = yes" by default. Ensure that neither is running.

Procedure:
Check if telnetd is running:

# ps -ef |grep telnetd

If the telnet daemon is running, this is a finding.

Check if telnetd is enabled on startup:

# chkconfig --list|grep telnet

If an entry with "on" is found, this is a finding.

Fix

Identify the telnet service running and disable it.

Procedure:

Disable the telnet server.
# chkconfig telnet off

Verify the telnet daemon is no longer running.
# ps -ef |grep telnet
V-24624 No Change
Findings ID: GEN008710 Rule ID: SV-63097r1_rule Severity: medium CCI: CCI-000213

Discussion

If system boot loader passwords are compromised, users with console access to the system may be able to alter the system boot configuration or boot the system into single user or maintenance mode, which could result in Denial of Service or unauthorized privileged access to the system.System Administrator

Checks

Check GRUB for password configuration.

Procedure:
Check the /boot/grub/grub.conf or /boot/grub/menu.lst files.
# grep "password" /boot/grub/grub.conf /boot/grub/menu.lst

Check for a password configuration line, such as:
password --md5 <password-hash>

If the boot loader passwords are not protected using an MD5 hash or stronger, this is a finding.

Fix

Consult vendor documentation for procedures concerning the system's boot loader. Configure the boot loader to hash boot loader passwords using MD5 or a stronger hash.
V-27250 No Change
Findings ID: GEN000140-2 Rule ID: SV-63101r1_rule Severity: medium CCI: CCI-000293

Discussion

A file integrity baseline is a collection of file metadata which is to evaluate the integrity of the system. A minimal baseline must contain metadata for all device files, setuid files, setgid files, system libraries, system binaries, and system configuration files. The minimal metadata must consist of the mode, owner, group owner, and modification times. For regular files, metadata must also include file size and a cryptographic hash of the file's contents.System Administrator

Checks

Verify a system integrity baseline exists. The Advanced Intrusion Detection Environment (AIDE) tool is included with the operating system. Other host intrusion detection system (HIDS) software is available but must be checked manually.

Procedure:
# grep DBDIR /etc/aide.conf

If /etc/aide.conf does not exist AIDE has not been installed. Unless another HIDS is used on the system, this is a finding.

Examine the response for "database" this indicates the location of the system integrity baseline database used as input to a comparison.
# ls -la <DBDIR>

If no "database" file as defined in /etc/aide.conf exists a system integrity baseline has not been created, this is a finding.

Examine /etc/aide.conf to ensure some form of cryptographic hash (i.e., md5, rmd160, sha256) is used for files. In the default /etc/aide.conf the "NORMAL" or "LSPP" rules which are used for virtually all files DO include some form of cryptographic hash.

If the site has defined rules to replace the functionality provided by the default "NORMAL" and "LSPP" rules but DOES NOT include cryptographic hashes, this is a finding.

Otherwise, if any element used to define the "NORMAL" and "LSPP" rules has been modified resulting in cryptographic hashes not being used, this is a finding.

If any other modification to the default /etc/aide.conf file have been made resulting in rules which do not include cryptographic hashes on appropriate files, this is a finding.

Fix

Use AIDE to create a file integrity baseline, including cryptographic hashes, for the system.

Configure the /etc/aide.conf file to ensure some form of cryptographic hash (e.g., md5, rmd160, sha256) is used for files. In the default /etc/aide.conf the "NORMAL" or "LSPP" rules which are used for virtually all files DO include some form of cryptographic hash.
V-27251 No Change
Findings ID: GEN000140-3 Rule ID: SV-63129r1_rule Severity: medium CCI: CCI-000293

Discussion

A file integrity baseline is a collection of file metadata which is to evaluate the integrity of the system. A minimal baseline must contain metadata for all device files, setuid files, setgid files, system libraries, system binaries, and system configuration files. The minimal metadata must consist of the mode, owner, group owner, and modification times. For regular files, metadata must also include file size and a cryptographic hash of the file's contents.System Administrator

Checks

Verify a system integrity baseline is maintained. The baseline has been updated to be consistent with the latest approved system configuration changes. The Advanced Intrusion Detection Environment (AIDE) tool is included with the operating system. Other host intrusion detection system (HIDS) software is available but must be checked manually.

Procedure:
# grep DBDIR /etc/aide.conf

If /etc/aide.conf does not exist AIDE has not been installed. Unless another HIDS is used on the system, this is a finding.

Examine the response for "database" indicates the location of the system integrity baseline database used as input to a comparison.
# ls -la <DBDIR>

If the no "database" file as defined in /etc/aide.conf a system integrity baseline has not been created, this is a finding.

Ask the SA when the last approved system configuration changes occurred. If the modification date of the AIDE database is prior to the last approved configuration change, this is a finding.

Fix

Regularly rebuild the integrity baseline, including cryptographic hashes, for the system to be consistent with the latest approved system configuration.

Procedure:
After an approved modification to the system configuration has been made perform:

# aide -u
This will update the database.
V-27275 No Change
Findings ID: GEN000290-2 Rule ID: SV-63215r2_rule Severity: medium CCI: CCI-000012

Discussion

Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.System Administrator

Checks

Check the system for the unnecessary "news" accounts.

Procedure:
# rpm -q inn
If the "inn" is installed the "news" user is necessary and this is not a finding.

# grep ^news /etc/passwd
If this account exists and "inn" is not installed, this is a finding.

Fix

Remove the "news" account from the /etc/passwd file before connecting a system to the network.
V-27276 No Change
Findings ID: GEN000290-3 Rule ID: SV-63227r2_rule Severity: medium CCI: CCI-000012

Discussion

Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.System Administrator

Checks

Check the system for the unnecessary "gopher" accounts.

Procedure:
# grep ^gopher /etc/passwd
If this account exists, it is a finding.

Fix

Remove the "gopher" account from the /etc/passwd file before connecting a system to the network.
V-27279 No Change
Findings ID: GEN000290-4 Rule ID: SV-63231r2_rule Severity: medium CCI: CCI-000012

Discussion

Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.System Administrator

Checks

Check the system for the unnecessary "ftp" accounts.

Procedure:
# rpm -q krb5-workstation
An ftp server is part of "krb5-workstation". If it is installed the "ftp" user is necessary and this is not a finding.

# rpm -q vsftp
If the "vsftp" ftp server is installed the "ftp" user is necessary and this is not a finding.

# grep ^ftp /etc/passwd
If this account exists and no ftp server is installed which requires it, this is a finding.

Fix

Remove the "ftp" account from the /etc/passwd file before connecting a system to the network.
V-27283 No Change
Findings ID: GEN000500-2 Rule ID: SV-63609r1_rule Severity: medium CCI: CCI-000057

Discussion

If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients.System Administrator

Checks

If the "xorg-x11-server-Xorg" package is not installed, this is not applicable.

For the Gnome screen saver, check the idle_delay setting.

Procedure:
# gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/idle_delay
If this does not return 15 or less, this is a finding.

Fix

For the Gnome screen saver, set idle_delay to 15.

Procedure:
# gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type int --set /apps/gnome-screensaver/idle_delay 15
V-27284 No Change
Findings ID: GEN000500-3 Rule ID: SV-63619r1_rule Severity: medium CCI: CCI-000057

Discussion

If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients.System Administrator

Checks

If the "xorg-x11-server-Xorg" package is not installed, this is not applicable.

For the Gnome screen saver, check the lock_enabled flag.

Procedure:
# gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/lock_enabled
If this does not return "true", this is a finding.

Fix

For the Gnome screen saver, set the lock_enabled flag.

Procedure:
# gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type bool --set /apps/gnome-screensaver/lock_enabled true
V-27285 No Change
Findings ID: GEN000600-2 Rule ID: SV-63987r1_rule Severity: medium CCI: CCI-000192

Discussion

Pam global requirements are generally defined in the /etc/pam.d/system-auth or /etc/pam.d/system-auth-ac file. In order for the requirements to be applied the file containing them must be included directly or indirectly in each program's definition file in /etc/pam.d

System Administrator

Checks

Verify the system-auth settings are being applied.

Procedure:
Verify the additional pam.d requirements are in use.

The file "/etc/pam.d/system-auth-ac" is auto generated by "authconfig". Any manual changes made to it will be lost next time "authconfig" is run.
Check to see if the systems default of the symlink "/etc/pam.d/system-auth" pointing to "/etc/pam.d/system-auth-ac" has been changed.

# ls -l /etc/pam.d/system-auth

If the symlink points to "/etc/pam.d/system-auth-ac", manual changes cannot be protected. This is a finding.

# grep system-auth-ac /etc/pam.d/system-auth

The local system-auth file pointed to by "/etc/pam.d/system-auth" must contain "/etc/pam.d/system-auth-ac" for the auth, account, password, and session lines. If it does not then the parameters maintained by "authconfig" will not be applied, this is a finding.

Fix

By default, the operating system delivers /etc/pam.d/system-auth as a symbolic link to /etc/pam.d/system-auth-ac (an automatically generated file). When a site adds password requirements a new system-auth-local file must be created with only the additional requirements and includes for auth, account, passwd and session pointing to "/etc/pam.d/system-auth-ac". Then the symlink "/etc/system-auth" is modified to point to "/etc/pam.d/system-auth-local". This way any changes made do not get lost when "/etc/pam.d/system-auth-ac" is regenerated and each program's pam.d definition file need only have "include system-auth" for auth, account, passwd and session, as needed, in order to assure the password requirements will be applied to it.
V-29236 No Change
Findings ID: GEN002720-2 Rule ID: SV-64249r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check that auditd is configured to audit failed file access attempts.
There must be an audit rule for each of the access syscalls that logs all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S open" | grep -e "-F success=0"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S open" | grep -e "-F exit=-EPERM"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S open" | grep -e "-F exit=-EACCES"

If an "-S open" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "open" exist, then this is a finding.

Fix

Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs:

either:
-a exit,always -F arch=<ARCH> -S open -F success=0

or both:
-a exit,always -F arch=<ARCH> -S open -F exit=-EPERM
-a exit,always -F arch=<ARCH> -S open -F exit=-EACCES

Restart the auditd service.
# service auditd restart
V-29237 No Change
Findings ID: GEN002720-3 Rule ID: SV-64255r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System AdministratorECAR-1, ECAR-2, ECAR-3

Checks

Verify auditd is configured to audit failed file access attempts.
There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall.

Procedure:

# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S openat" | grep -e "-F success=0"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S openat" | grep -e "-F exit=-EPERM"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S openat" | grep -e "-F exit=-EACCES"

If an "-S openat" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "openat" exist, then this is a finding.

Fix

Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs:

either:
-a exit,always -F arch=<ARCH> -S openat -F success=0

or both:
-a exit,always -F arch=<ARCH> -S openat -F exit=-EPERM
-a exit,always -F arch=<ARCH> -S openat -F exit=-EACCES

Restart the auditd service.
# service auditd restart
V-29238 No Change
Findings ID: GEN002720-4 Rule ID: SV-64257r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System AdministratorECAR-1, ECAR-2, ECAR-3

Checks

Verify auditd is configured to audit failed file access attempts.
There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or
there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall.

Procedure:

# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S truncate" | grep -e "-F success=0"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S truncate" | grep -e "-F exit=-EPERM"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S truncate" | grep -e "-F exit=-EACCES"

If an "-S truncate" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "truncate" exist, then this is a finding.

Fix

Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs:

either:
-a exit,always -F arch=<ARCH> -S truncate -F success=0

or both:
-a exit,always -F arch=<ARCH> -S truncate -F exit=-EPERM
-a exit,always -F arch=<ARCH> -S truncate -F exit=-EACCES

Restart the auditd service.
# service auditd restart
V-29239 No Change
Findings ID: GEN002720-5 Rule ID: SV-64259r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System AdministratorECAR-1, ECAR-2, ECAR-3

Checks

Verify auditd is configured to audit failed file access attempts.
There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or
there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S ftruncate" | grep -e "-F success=0"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S ftruncate" | grep -e "-F exit=-EPERM"
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S ftruncate" | grep -e "-F exit=-EACCES"

If an "-S ftruncate" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "ftruncate" exist, then this is a finding.

Fix

Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs:

either:
-a exit,always -F arch=<ARCH> -S ftruncate -F success=0

or both:
-a exit,always -F arch=<ARCH> -S ftruncate -F exit=-EPERM
-a exit,always -F arch=<ARCH> -S ftruncate -F exit=-EACCES

Restart the auditd service.
# service auditd restart
V-29240 No Change
Findings ID: GEN002740-2 Rule ID: SV-64265r1_rule Severity: medium CCI: CCI-000126

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the system audit configuration to determine if file and directory deletions are audited.

# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "rmdir"

If no results are returned, or the results do not contain "-S rmdir", this is a finding.

Fix

The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.

Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement and are a finding unless justified and documented appropriately.

The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.

Procedure:

Edit the /etc/audit/audit.rules file, and add one or more the lines (subject to the dual-architecture discussion above) to enable auditing of deletions:

-a exit,always -F arch=<ARCH> -S rmdir

Restart the auditd service:

# service auditd restart
V-29241 No Change
Findings ID: GEN002760-2 Rule ID: SV-64471r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:

# cat /etc/audit/audit.rules | grep -i "audit.rules"

If no results are returned, or the line does not start with "-w", this is a finding.

Fix

The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.

Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-w /etc/audit/audit.rules

Restart the auditd service.
# service auditd restart
V-29242 No Change
Findings ID: GEN002760-3 Rule ID: SV-64481r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "adjtimex"

If the result does not contain "-S adjtimex", this is a finding.

Fix

The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.
On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.
Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.
The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.
Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-a exit,always -F arch=<ARCH> -S adjtimex

Restart the auditd service.
# service auditd restart
V-29243 No Change
Findings ID: GEN002760-4 Rule ID: SV-64489r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "settimeofday"

If the result does not contain "-S settimeofday", this is a finding.

Fix

The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.
On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.
Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.
The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.
Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-a exit,always -F arch=<ARCH> -S settimeofday

Restart the auditd service.
# service auditd restart
V-29244 No Change
Findings ID: GEN002760-5 Rule ID: SV-64491r2_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "stime"

# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "settimeofday"

If the result does not contain "-S stime" or "-S settimeofday ", this is a finding.

The "stime" keyword is only required on systems using an i386 architecture.

Fix

The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.
On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.
Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.
The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.
Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-a exit,always -F arch=<ARCH> -S stime (only used for systems using an i386 architecture)
-a exit,always -F arch=<ARCH> -S settimeofday (used on all non-i386 architectures such as b64 and x86_64)

Restart the auditd service.
# service auditd restart
V-29245 No Change
Findings ID: GEN002760-6 Rule ID: SV-64529r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "clock_settime"

If the result does not contain "-S clock_settime", this is a finding.

Fix

The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.
On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.
Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.
The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.
Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-a exit,always -F arch=<ARCH> -S clock_settime

Restart the auditd service.
# service auditd restart
V-29246 No Change
Findings ID: GEN002760-7 Rule ID: SV-64543r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "sethostname"

If the result does not contain "-S sethostname", this is a finding.

Fix

The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.
On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.
Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.
The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.
Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-a exit,always -F arch=<ARCH> -S sethostname

Restart the auditd service.
# service auditd restart
V-29247 No Change
Findings ID: GEN002760-8 Rule ID: SV-64551r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "setdomain"

If the result does not contain "-S setdomain", this is a finding.

Fix

The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules.

On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details.

Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately.

The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding.

Procedure:
Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions:

-a exit,always -F arch=<ARCH> -S setdomainname

Restart the auditd service.
# service auditd restart
V-29248 No Change
Findings ID: GEN002760-9 Rule ID: SV-64555r1_rule Severity: medium CCI: CCI-000347

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.System Administrator

Checks

Check the auditing configuration of the system.

Procedure:
# cat /etc/audit/audit.rule