Profile Applicability:
 Level 1


Description:
 Duplicate User IDs (UIDs) can cause conflicts in user identification, permissions, and auditing. Ensuring unique UIDs maintains system integrity and prevents unauthorized access or privilege escalation.

Rationale:
 Preventing duplicate UIDs avoids confusion in user management and reduces risks related to identity and access control.

Impact:
 Pros:

  • Maintains clear and consistent user identity management.

  • Simplifies auditing and access control.

Cons:

  • Renaming or removing duplicate user accounts may disrupt workflows if not carefully handled.

Default Value:
 Duplicate UIDs may exist due to misconfiguration or manual errors.

Pre-requisites:

  • Root or sudo privileges to review and modify user accounts.

Remediation:

Test Plan:

Using Linux command line:

  1. List all UIDs and identify duplicates:

    cut -d: -f3 /etc/passwd | sort | uniq -d

  2. Verify that the output is empty, indicating no duplicates.

Implementation Plan:

Using Linux command line:

  1. For each duplicate UID found, change the UID to a unique value:

    usermod -u <new_uid> <username>

  2. Ensure user files and permissions are updated accordingly.

Backout Plan:

Using Linux command line:

  1. Restore original UIDs from backups if needed.

  2. Reassign ownership of files and permissions if necessary.

References: