cis-ubuntu2004-v300-5-4-1-3

DevOps & Security

Ensure password expiration warning days is configured

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5.4.1.3 Ensure password expiration warning days is configured (Automated)

Profile

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.

PASS_WARN_AGE - The number of days warning given before a password expires. A zero means warning is given only upon the day of expiration, a negative value means no warning is given. If not specified, no warning will be provided.

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 and follows local site policy:

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

Example output:

PASS_WARN_AGE 7

Run the following command to verify all passwords have a PASS_WARN_AGE of 7 or more:

# awk -F: '($2~/^\$.+\$/) {if($6 < 7)print "User: " $1 " PASS_WARN_AGE: " $6}' /etc/shadow

Expected Result

Nothing should be returned

Remediation

Command Line

Edit /etc/login.defs and set PASS_WARN_AGE to a value of 7 or more that follows local site policy: Example:

PASS_WARN_AGE 7

Run the following command to modify user parameters for all users with a password set to a minimum warning to 7 or more days that follows local site policy:

# chage --warndays <N> <user>

Example:

# awk -F: '($2~/^\$.+\$/) {if($6 < 7)system ("chage --warndays 7 " $1)}' /etc/shadow

Default Value

PASS_WARN_AGE 7

References

None specified.

CIS Controls

v8 - 5.2 Use Unique Passwords: Use unique passwords for all enterprise assets. Best practice implementation includes, at a minimum, an 8-character password for accounts using MFA and a 14-character password for accounts not using MFA. (IG 1, IG 2, IG 3)

v7 - 4.4 Use Unique Passwords: Where multi-factor authentication is not supported (such as local administrator, root, or service accounts), accounts will use passwords that are unique to that system. (IG 2, IG 3)

MITRE ATT&CK Mappings: T1078 - Tactics: TA0006 - Mitigations: M1027