Title

The Red Hat Enterprise Linux operating system must be configured so that passwords are prohibited from reuse for a minimum of five generations. (Cat II impact)

Discussion

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the end result is a password that is not changed per policy requirements.

Check Content

Verify the operating system prohibits password reuse for a minimum of five generations. Check for the value of the "remember" argument in "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" with the following command: # grep -i remember /etc/pam.d/system-auth /etc/pam.d/password-auth password requisite pam_pwhistory.so use_authtok remember=5 retry=3 If the line containing the "pam_pwhistory.so" line does not have the "remember" module argument set, is commented out, or the value of the "remember" module argument is set to less than "5", this is a finding.

Fix Text

Configure the operating system to prohibit password reuse for a minimum of five generations. Add the following line in "/etc/pam.d/system-auth" (or modify the line to have the required value): password requisite pam_pwhistory.so remember=5 retry=3 Add the following line in "/etc/pam.d/password-auth" (or modify the line to have the required value): password requisite pam_pwhistory.so use_authtok remember=5 retry=3 Note: Per requirement RHEL-07-010199, RHEL 7 must be configured to not overwrite custom authentication configuration settings while using the authconfig utility; otherwise, manual changes to the listed files will be overwritten whenever the authconfig utility is used.

Additional Identifiers

Rule ID: SV-204422r917818_rule

Vulnerability ID: V-204422

Group Title: SRG-OS-000077-GPOS-00045

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.