The Ubuntu operating system must not allow accounts configured with blank or null passwords.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-251504	UBTU-20-010463	SV-251504r1082230_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 should never be used in operational environments.

STIG	Date
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide	2025-05-16

Details

Check Text (C-54939r1082228_chk)

Verify null passwords cannot be used. Run the following command:

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

If this produces any output, it may be possible to log on with accounts with empty passwords.

If null passwords can be used, this is a finding.

Fix Text (F-54893r1082229_fix)

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

Remove any instances of the "nullok" option in "/etc/pam.d/common-auth" and "/etc/pam.d/common-password".