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

DISA STIG library V2R10
All changes in this version
first version loaded CAT I

Maps to AC-3 via CCI-000213

Title

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

Control

Verify the RHEL 9 boot loader superuser account has been set with the following command: $ sudo grep -A1 "superusers" /etc/grub2.cfg set superusers="" export superusers password_pbkdf2 ${GRUB2_PASSWORD} Verify is not a common name such as root, admin, or administrator. If superusers contains easily guessable usernames, this is a finding.

Discussion

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

Related controls

CCI-000213

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="" 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