cis-ubuntu1804-v220-4-5-1-3

name	cis-ubuntu1804-v220-4-5-1-3
description	Ensure password expiration warning days is 7 or more
category	cis-iam
version	2.2.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-18.04","users","password-policy"]
cis_id	4.5.1.3
cis_benchmark	CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 4.5.1.3

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Description

The PASS_WARN_AGE parameter in /etc/login.defs allows an administrator to notify users that their password will expire in a defined number of days. It is recommended that the PASS_WARN_AGE parameter be set to 7 or more days.

Rationale

Providing an advance warning that a password will be expiring gives users time to think of a secure password. Users caught unaware may choose a simple password or write it down where it may be discovered.

Audit Procedure

Command Line

Run the following command and verify PASS_WARN_AGE is 7 or more:

grep -Pi '^\h*PASS_WARN_AGE\h+\d+\b' /etc/login.defs

Verify all users with a password have their warning days set:

awk -F: '($2~/^\$.+\$/){print $1 " " $6}' /etc/shadow

Expected Result

PASS_WARN_AGE should be 7 or more in /etc/login.defs.

No user should have a value less than 7 in field 6 of /etc/shadow.

Remediation

Command Line

Set the PASS_WARN_AGE parameter to 7 in /etc/login.defs:

PASS_WARN_AGE 7

Modify user parameters for all users with a password set to match:

chage --warndays 7 <user>

Default Value

PASS_WARN_AGE 7

References

1. NIST SP 800-53 Rev. 5: IA-5, CM-6

CIS Controls

v8 - 5.2 Use Unique Passwords - Use unique passwords for all enterprise assets.

v7 - 4.4 Use Unique Passwords.

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Assessment Status

Automated