CVE-2021-39909 : Exploit Details and Defense Strategies

A security vulnerability has been identified in GitLab that could allow an attacker to bypass CODEOWNERS Merge Request approval requirement under certain conditions.

Understanding CVE-2021-39909

This section provides an overview of the CVE-2021-39909 vulnerability in GitLab.

What is CVE-2021-39909?

The lack of email address ownership verification in the CODEOWNERS feature in select versions of GitLab allows an attacker to bypass CODEOWNERS Merge Request approval.

The Impact of CVE-2021-39909

The vulnerability has a base severity rating of MEDIUM with a CVSS base score of 5.3. Here are the key impact details:

Attack Complexity: HIGH
Attack Vector: NETWORK
Integrity Impact: HIGH
Privileges Required: LOW

Technical Details of CVE-2021-39909

This section delves into the technical aspects of the CVE-2021-39909 vulnerability.

Vulnerability Description

The vulnerability stems from the lack of email address ownership verification in the CODEOWNERS feature within specific GitLab versions.

Affected Systems and Versions

GitLab versions affected by this vulnerability include:

Versions >=11.3, <14.2.6
Versions >=14.3, <14.3.4
Versions >=14.4, <14.4.1

Exploitation Mechanism

Attackers can exploit this vulnerability under rare circumstances by leveraging the absence of email address verification.

Mitigation and Prevention

Learn how to mitigate the CVE-2021-39909 vulnerability in GitLab.

Immediate Steps to Take

Upgrade GitLab to a non-vulnerable version.
Implement email address verification controls.

Long-Term Security Practices

Regularly review and update security policies.
Conduct security trainings for the team.

Patching and Updates

Keep GitLab up to date with the latest security patches.