# Ensure No Duplicate GIDs Exist on the System

- Source: https://support.icompaas.com/support/solutions/articles/62000235394-ensure-no-duplicate-gids-exist-on-the-system
- Section: [Solutions](https://support.icompaas.com/support/solutions) › [CIS Amazon Linux 2 Benchmark v3.0.0](https://support.icompaas.com/support/solutions/62000112696) › [CIS Amazon Linux 2 Benchmarks](https://support.icompaas.com/support/solutions/folders/62000169265)
- Last updated: 2026-05-29
- Publisher: iCompaas, Inc. (https://www.icompaas.com)

Profile Applicability: Level 1

  

Description:  
Duplicate Group IDs (GIDs) can cause conflicts in group ownership and permissions, potentially leading to unauthorized access or privilege escalation.

Rationale:  
 Ensuring unique GIDs prevents ambiguity in group membership and access control, maintaining system security and integrity.

**Impact:  
** **Pros:**

-   Ensures consistent group permissions and ownership.
    
-   Simplifies management and auditing of groups.
    

**Cons:**

-   Changing GIDs may disrupt access if not properly coordinated.
    

Default Value:  
 Duplicate GIDs may exist due to manual misconfiguration or system inconsistencies.

Pre-requisites:

-   Root or sudo privileges to review and modify group configurations.
    

Remediation:

### Test Plan:

Using Linux command line:

1.  List all GIDs and identify duplicates:
    
    cut -d: -f3 /etc/group | sort | uniq -d
    
2.  Verify that the output is empty, indicating no duplicates.  
    

Implementation Plan:

Using Linux command line:

1.  For each duplicate GID found, change the GID to a unique value:
    
    groupmod -g <new\_gid> <groupname>
    
2.  Update any files or directories with the old GID to the new GID.  
    

Backout Plan:

Using Linux command line:

1.  Restore original GIDs from backups if necessary.
    
2.  Revert file and directory ownership as required.
    

References:

-   CIS Amazon Linux 2 Benchmark v3.0.0  
    
-   [NIST SP 800-53 Revision 5 - AC-6  
      
    ](https://csrc.nist.gov/publications/detail/sp/800-53/rev-5/final#ac-6)

## Related compliance guidance

- [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Configuration checks like this one are the technical half of a SOC 2 / ISO 27001 programme — the guide shows where they fit, what else an auditor expects, and how to evidence them.
- [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): ISO 27001 Annex A.8 (technological controls) is where cloud hardening evidence lands; the guide shows how to run the ISMS around it.