RHEL 9 must require a unique superusers name upon booting into single-user and maintenance modes.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| high | V-257789 | SRG-OS-000080-GPOS-00048 | RHEL-09-212020 | SV-257789r1137691_rule | 2026-02-05 | 2 |
Description
Having a nondefault grub superuser username makes password-guessing attacks less effective.
ℹ️ Check
Verify the RHEL 9 boot loader superuser account has been set with the following command:
$ sudo grep -A1 "superusers" /etc/grub2.cfg
set superusers="<accountname>"
export superusers
password_pbkdf2 <accountname> ${GRUB2_PASSWORD}
Verify <accountname> is not a common name such as root, admin, or administrator.
If superusers contains easily guessable usernames, this is a finding.
✔️ 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 with a nondefault username for the superuser account:
set superusers="<accountname>"
export superusers
Once the superuser account has been added, update the grub.cfg file by running:
In RHEL 9.0, 9.1 and 9.2:
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
In RHEL 9.3 and later:
sudo grub2-mkconfig -o /boot/grub2/grub.cfg --update-bls-cmdline