RHEL 9 must require a unique superusers name upon booting into single-user and maintenance modes.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-257789	RHEL-09-212020	SV-257789r943055_rule		High

Description
Having a nondefault grub superuser username makes password-guessing attacks less effective.

STIG	Date
Red Hat Enterprise Linux 9 Security Technical Implementation Guide	2023-12-01

Details

Check Text ( C-61530r943053_chk )
Verify the boot loader superuser account has been set with the following command: $ sudo grep -A1 "superusers" /etc/grub2.cfg set superusers="" export superusers The is the actual account name different from common names like root, admin, or administrator. If superusers contains easily guessable usernames, this is a finding.

Fix Text (F-61454r943054_fix)
Configure RHEL 9 to have a unique username for the grub superuser account. Edit the "/etc/grub.d/01_users" file and add or modify the following lines in the "### BEGIN /etc/grub.d/01_users ###" section: set superusers="superusers-account" export superusers Once the superuser account has been added, update the grub.cfg file by running: $ sudo grubby --update-kernel=ALL