cis-gcp-cos-5-2-2

name	cis-gcp-cos-5.2.2
description	Ensure password reuse is limited
category	cis-gcp-cos
version	1.2.0
author	cyberstrike-official
tags	["cis","gcp","container-optimized-os","pam","password-policy","password-reuse"]
cis_id	5.2.2
cis_benchmark	CIS Google Container-Optimized OS Benchmark v1.2.0
tech_stack	["gcp","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

5.2.2 Ensure password reuse is limited (Manual)

Description

The /etc/security/opasswd file stores the users' old passwords and can be checked to ensure that users are not recycling recent passwords.

Rationale

Forcing users not to reuse their past 5 passwords make it less likely that an attacker will be able to guess the password.

Note that these change only apply to accounts configured on the local system.

Audit Procedure

Verify remembered password history is 5 or more. This setting is commonly configured with the pam_unix.so or pam_pwhistory.so remember options found in /etc/pam.d/common-password or /etc/pam.d/system-auth. Examples:

password required pam_pwhistory.so remember=5
password required pam_unix.so remember=5

Expected Result

The remember option should be set to 5 or more in the PAM configuration for pam_pwhistory.so or pam_unix.so.

Remediation

Set remembered password history to conform to site policy. Many distributions provide tools for updating PAM configuration, consult your documentation for details. If no tooling is provided edit the appropriate /etc/pam.d/ configuration file and add or modify the pam_pwhistory.so or pam_unix.so lines to include the remember option:

password required pam_pwhistory.so remember=5
password required pam_unix.so remember=5

Additional Information:

Consult your documentation for the appropriate PAM file and module.

Additional module options may be set, recommendation only covers those listed here.

Profile

• Level 2 - Server