| name | cis-ubuntu1804-v220-1-4-2 |
| description | Ensure permissions on bootloader config are configured |
| category | cis-storage |
| version | 2.2.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-18.04","grub","bootloader","permissions","secure-boot"] |
| cis_id | 1.4.2 |
| cis_benchmark | CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
1.4.2 Ensure permissions on bootloader config are configured (Automated)
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Description
The grub configuration file contains information on boot settings and passwords for unlocking boot options.
Rationale
Setting the permissions to read and write for root only prevents non-root users from seeing the boot parameters or changing them. Non-root users who read the boot parameters may be able to identify weaknesses in security upon boot and be able to exploit them.
Audit Procedure
Command Line
Run the following command and verify Uid and Gid are both 0/root and Access is 0600 or more restrictive:
stat /boot/grub/grub.cfg
Expected Result
Access: (0600/-r--------) Uid: ( 0/ root) Gid: ( 0/ root)
Remediation
Command Line
Run the following commands to set permissions on your grub configuration:
chown root:root /boot/grub/grub.cfg
chmod u-x,go-rwx /boot/grub/grub.cfg
Additional Information
This recommendation is designed around the grub bootloader, if LILO or another bootloader is in use in your environment enact equivalent settings.
Replace /boot/grub/grub.cfg with the appropriate grub configuration file for your environment.
References
- NIST SP 800-53 Rev. 5: CM-6
CIS Controls
| Controls Version | Control | IG 1 | IG 2 | IG 3 |
|---|
| v8 | 3.3 Configure Data Access Control Lists | X | X | X |
| v7 | 14.6 Protect Information through Access Control Lists | X | X | X |
MITRE ATT&CK Mappings
| Techniques / Sub-techniques | Tactics | Mitigations |
|---|
| T1542, T1542.000 | TA0005, TA0007 | M1022 |
