CVE-2023-6804 : Exploit Details and Defense Strategies

This CVE, assigned by GitHub, highlights a critical vulnerability related to improper privilege management in GitHub Enterprise Server, affecting versions 3.8 to 3.11.

Understanding CVE-2023-6804

This vulnerability allowed malicious actors to execute arbitrary workflows by leveraging improperly scoped Personal Access Tokens (PATs) due to a flaw in privilege management. The exploit required the presence of a workflow within the target repository.

What is CVE-2023-6804?

The CVE-2023-6804 vulnerability in GitHub Enterprise Server enabled attackers to bypass privilege restrictions and execute unauthorized workflows using PATs. This could potentially lead to unauthorized access and data manipulation within the affected systems.

The Impact of CVE-2023-6804

The impact of CVE-2023-6804, categorized under CAPEC-233 (Privilege Escalation), can result in a medium-severity attack with high confidentiality and integrity impacts. The exploit complexity is high, with low privileges required for execution.

Technical Details of CVE-2023-6804

This section delves into the specifics of the vulnerability, including its description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability stemmed from improper privilege management, allowing threat actors to execute arbitrary workflows using improperly scoped PATs within GitHub Enterprise Server instances. The exploit required pre-existing workflows in the target repository.

Affected Systems and Versions

All versions of GitHub Enterprise Server from 3.8 to 3.11 were impacted by this vulnerability. GitHub addressed this issue in version 3.8.12, 3.9.7, 3.10.4, and 3.11.1, providing fixes to prevent further exploitation.

Exploitation Mechanism

By manipulating improperly scoped PATs, attackers could bypass privilege restrictions and initiate unauthorized workflows within GitHub Enterprise Server instances. This exploitation method could lead to unauthorized operations within the affected systems.

Mitigation and Prevention

To safeguard against CVE-2023-6804 and similar vulnerabilities, immediate actions and long-term security practices are essential. Additionally, applying necessary patches and updates is crucial to mitigate the risk of exploitation.

Immediate Steps to Take

Organizations should update their GitHub Enterprise Server instances to the patched versions (3.8.12, 3.9.7, 3.10.4, 3.11.1) to eliminate the vulnerability.
Review and revoke unnecessary permissions and access rights within the GitHub repositories to limit potential attack vectors.

Long-Term Security Practices

Regularly audit and review privilege assignments and access controls to ensure proper security measures are in place.
Educate users on secure coding practices, including the appropriate use of PATs and workflows to prevent unauthorized executions.

Patching and Updates

GitHub's release notes for versions 3.8.12, 3.9.7, 3.10.4, and 3.11.1 provide detailed information on the fixes implemented to address the CVE-2023-6804 vulnerability. It is crucial for organizations to stay informed about security patches and promptly apply them to protect their systems.