CVE-2021-41599 : Exploit Details and Defense Strategies

A remote code execution vulnerability was identified in GitHub Enterprise Server that could be exploited when building a GitHub Pages site. This CVE affected versions of GitHub Enterprise Server prior to 3.3 and was fixed in versions 3.0.21, 3.1.13, and 3.2.5.

Understanding CVE-2021-41599

What is CVE-2021-41599?

This CVE describes an improper control flow in GitHub Enterprise Server that could lead to remote code execution when hosting GitHub Pages, requiring attacker permission to create and build a GitHub Pages site on the affected server.

The Impact of CVE-2021-41599

The vulnerability allowed attackers to execute remote code on the server hosting GitHub Pages, potentially leading to unauthorized data access, manipulation, or further system compromise.

Technical Details of CVE-2021-41599

Vulnerability Description

The vulnerability stemmed from improper control flow in GitHub Enterprise Server when processing hosted Pages, enabling a malicious actor to execute arbitrary code.

Affected Systems and Versions

Affected Systems: GitHub Enterprise Server
Affected Versions: All versions prior to 3.3

Exploitation Mechanism

The vulnerability could be exploited by an attacker with permissions to create and build a GitHub Pages site on the vulnerable GitHub Enterprise Server instance.

Mitigation and Prevention

Immediate Steps to Take

Upgrade GitHub Enterprise Server to version 3.3 or newer to mitigate the vulnerability.
Monitor for any unauthorized changes or activities on GitHub Pages.

Long-Term Security Practices

Regularly review and apply security updates provided by GitHub for GitHub Enterprise Server.
Enforce the principle of least privilege to restrict user permissions and access.

Patching and Updates

Apply patches and updates promptly to ensure the security of GitHub Enterprise Server and hosted services.