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-257789r1044841_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 | 2024-12-04 |
Details
| Check Text (C-61530r1044839_chk) |
| Verify the 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 Text (F-61454r1044840_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: $ sudo grubby --update-kernel=ALL |