Verify the UEFI Boot Loader grub.cfg User Ownership
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The file /boot/efi/EFI/redhat/grub.cfg
should
be owned by the root
user to prevent destruction
or modification of the file.
To properly set the owner of /boot/efi/EFI/redhat/grub.cfg
, run the command:
$ sudo chown root /boot/efi/EFI/redhat/grub.cfg
Rationale
Only root should be able to modify important boot parameters.
Shell script
The following script can be run on the host to remediate the issue.
#!/bin/bash
# Remediation is applicable only in certain platforms
if [ -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
chown 0 /boot/efi/EFI/redhat/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Ansible playbook
The following playbook can be run with Ansible to remediate the issue.
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83429-1
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
stat:
path: /boot/efi/EFI/redhat/grub.cfg
register: file_exists
when:
- '"/boot/efi" in ansible_mounts | map(attribute="mount") | list'
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83429-1
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /boot/efi/EFI/redhat/grub.cfg
file:
path: /boot/efi/EFI/redhat/grub.cfg
owner: '0'
when:
- '"/boot/efi" in ansible_mounts | map(attribute="mount") | list'
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83429-1
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed