Passwords must be prohibited from reuse for a minimum of five generations.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-71933	RHEL-07-010270	SV-86557r2_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 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.

STIG	Date
Red Hat Enterprise Linux 7 Security Technical Implementation Guide	2017-12-14

Details

Check Text ( C-72165r1_chk )
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-ac" with the following command: # grep -i remember /etc/pam.d/system-auth-ac password sufficient pam_unix.so use_authtok sha512 shadow remember=5 If the line containing the "pam_unix.so" line does not have the "remember" module argument set, or the value of the "remember" module argument is set to less than "5", this is a finding.

Check Text ( C-72165r1_chk )

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-ac" with the following command:

# grep -i remember /etc/pam.d/system-auth-ac
password sufficient pam_unix.so use_authtok sha512 shadow remember=5

If the line containing the "pam_unix.so" line does not have the "remember" module argument set, or the value of the "remember" module argument is set to less than "5", this is a finding.

Fix Text (F-78285r2_fix)
Configure the operating system to prohibit password reuse for a minimum of five generations. Add the following line in "/etc/pam.d/system-auth-ac" (or modify the line to have the required value): password sufficient pam_unix.so use_authtok sha512 shadow remember=5