Title

The system must require authentication before allowing modification of the boot devices or menus. Secure the GRUB Menu (Intel). (Cat III impact)

Discussion

The flexibility that GRUB provides creates a security risk if its configuration is modified by an unauthorized user. The failsafe menu entry needs to be secured in the same environments that require securing the systems firmware to avoid unauthorized removable media boots.

Check Content

This check applies to X86 systems only. This check applies to the global zone only. Determine the zone that you are currently securing. # zonename If the command output is "global", this check applies. # grep source /rpool/boot/grub/grub.cfg source $prefix/custom.cfg If the output does not contain "source $prefix/custom.cfg" on a line of its own, this is a finding. # grep superusers /rpool/boot/grub/custom.cfg. # grep password_pbkdf2 /rpool/boot/grub/custom.cfg If no superuser name and password are defined, this is a finding.

Fix Text

The root role is required. This action applies to the global zone only. Determine the zone that you are currently securing. # zonename If the command output is "global", this action applies. Update GRUB to use a custom configuration file. # pfedit /rpool/boot/grub/grub.cfg Insert the line: source $prefix/custom.cfg Create a password hash. # /usr/lib/grub2/bios/bin/grub-mkpasswd-pbkdf2 Enter password: Reenter password: Your PBKDF2 is ....... Copy the long password hash in its entirety. # pfedit /rpool/boot/grub/custom.cfg Insert the lines: set superusers="[username]" password_pbkdf2 [username] [password hash] Restart the system.

Additional Identifiers

Rule ID: SV-216218r603268_rule

Vulnerability ID: V-216218

Group Title: SRG-OS-000480

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.