RHEL 8 must be configured in the system-auth file to prohibit password reuse for a minimum of five generations.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-251717	RHEL-08-020221	SV-251717r902749_rule		Medium

Description
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 reuse their password consecutively when that password has exceeded its defined lifetime, the end result is a password that is not changed per policy requirements. RHEL 8 uses "pwhistory" consecutively as a mechanism to prohibit password reuse. This is set in both: /etc/pam.d/password-auth /etc/pam.d/system-auth. Note that manual changes to the listed files may be overwritten by the "authselect" program.

Description

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 reuse their password consecutively when that password has exceeded its defined lifetime, the end result is a password that is not changed per policy requirements. RHEL 8 uses "pwhistory" consecutively as a mechanism to prohibit password reuse. This is set in both: /etc/pam.d/password-auth /etc/pam.d/system-auth. Note that manual changes to the listed files may be overwritten by the "authselect" program.

STIG	Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2023-12-01

Details

Check Text ( C-55154r902747_chk )
Verify the operating system is configured in the system-auth file to prohibit password reuse for a minimum of five generations. Check for the value of the "remember" argument in "/etc/pam.d/system-auth" with the following command: $ sudo grep -i remember /etc/pam.d/system-auth password requisite pam_pwhistory.so use_authtok remember=5 retry=3 If the line containing "pam_pwhistory.so" 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.

Check Text ( C-55154r902747_chk )

Verify the operating system is configured in the system-auth file to prohibit password reuse for a minimum of five generations.

Check for the value of the "remember" argument in "/etc/pam.d/system-auth" with the following command:

$ sudo grep -i remember /etc/pam.d/system-auth

password requisite pam_pwhistory.so use_authtok remember=5 retry=3

If the line containing "pam_pwhistory.so" 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 (F-55108r902748_fix)
Configure the operating system in the system-auth file 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 use_authtok remember=5 retry=3