Ubuntu 24.04 LTS must not allow accounts configured in Pluggable Authentication Modules (PAM) with blank or null passwords.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-270714	UBTU-24-300028	SV-270714r1067119_rule		High

Description

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords must never be used in operational environments.

STIG	Date
Canonical Ubuntu 24.04 LTS Security Technical Implementation Guide	2025-05-16

Details

Check Text (C-74747r1066629_chk)

To verify null passwords cannot be used, run the following command:

$ grep nullok /etc/pam.d/common-password

If this produces any output, this is a finding.

Fix Text (F-74648r1066630_fix)

If an account is configured for password authentication but does not have an assigned password, it is possible to log on to the account without authenticating.

Remove any instances of the "nullok" option in "/etc/pam.d/common-password" to prevent logons with empty passwords.