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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75479	UBTU-16-010250	SV-90159r1_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 16.04 Security Technical Implementation Guide	2019-03-13

Details

Check Text ( C-75183r1_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-82107r1_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 files under "/etc/pam.d/" to prevent logons with empty passwords.