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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-214961	UBTU-16-010230	SV-214961r610931_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 as per policy requirements.

STIG	Date
Canonical Ubuntu 16.04 LTS Security Technical Implementation Guide	2020-12-09

Details

Check Text ( C-16160r284751_chk )
Verify that the Ubuntu operating system prevents passwords from being reused for a minimum of five generations by running the following command: # grep -i remember /etc/pam.d/common-password password [success=1 default=ignore] pam_unix.so obscure sha512 remember=5 rounds=5000 If the "remember" parameter value is not greater than or equal to "5", is commented out, or is not set at all this is a finding.

Check Text ( C-16160r284751_chk )

Verify that the Ubuntu operating system prevents passwords from being reused for a minimum of five generations by running the following command:

# grep -i remember /etc/pam.d/common-password

password [success=1 default=ignore] pam_unix.so obscure sha512 remember=5 rounds=5000

If the "remember" parameter value is not greater than or equal to "5", is commented out, or is not set at all this is a finding.

Fix Text (F-16158r284752_fix)
Configure the Ubuntu operating system prevents passwords from being reused for a minimum of five generations. Add or modify the "remember" parameter value to the following line in "/etc/pam.d/common-password" file: password [success=1 default=ignore] pam_unix.so obscure sha512 remember=5 rounds=5000