RHEL-09-212020 - RHEL 9 must require a unique superusers name upon booting into single-user and maintenance modes.

Information

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

Solution

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

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_9_V2R6_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-3, CAT|I, CCI|CCI-000213, Rule-ID|SV-257789r1134895_rule, STIG-ID|RHEL-09-212020, Vuln-ID|V-257789

Plugin: Unix

Control ID: d4ddb26300ed9582d38e09badaa15dde9c583cf84c509f93dc25dfd9a8ae59a6