The Ubuntu operating system must not be configured to allow blank or null passwords.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75479	UBTU-16-010250	SV-90159r2_rule		High

Description
If the operating system allows empty passwords, anyone could log on and run commands with the privileges. Empty passwords should never be used in operational environments.

STIG	Date
Canonical Ubuntu 16.04 Security Technical Implementation Guide	2020-05-29

Details

Check Text ( C-75183r2_chk )
To verify that null passwords cannot be used, run the following command: # grep pam_unix.so /etc/pam.d/* | grep nullok* 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-82107r2_fix)
Remove any instances of the "nullok" option in files under "/etc/pam.d/" to prevent logons with empty passwords.