CVE-2021-22864 : 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 due to unsafe configuration options. This CVE allowed attackers to execute arbitrary code on the GitHub Enterprise Server instance by exploiting user-controlled configuration settings.

Understanding CVE-2021-22864

This section provides an overview of the CVE-2021-22864 vulnerability found in GitHub Enterprise Server.

What is CVE-2021-22864?

CVE-2021-22864 is a remote code execution vulnerability that affected GitHub Enterprise Server. It allowed attackers to execute malicious code on the server by leveraging unsafe configuration options present in GitHub Pages.

The Impact of CVE-2021-22864

The vulnerability posed a significant risk as it enabled attackers to execute arbitrary code on the GitHub Enterprise Server instance, potentially leading to data breaches, server compromise, and unauthorized access.

Technical Details of CVE-2021-22864

This section delves into the technical aspects of the CVE-2021-22864 vulnerability.

Vulnerability Description

The vulnerability stemmed from user-controlled configuration options in GitHub Pages that could be exploited to override environment variables and achieve code execution on the GitHub Enterprise Server instance.

Affected Systems and Versions

GitHub Enterprise Server versions prior to 3.0.3 were affected by this vulnerability, specifically versions 2.21, 2.22, and 3.0. Users running versions earlier than the fixed releases were exposed to the risk of remote code execution.

Exploitation Mechanism

To exploit CVE-2021-22864, an attacker would need permission to create and build a GitHub Pages site on the GitHub Enterprise Server. By manipulating configuration options, the attacker could override environment variables and execute arbitrary code on the server.

Mitigation and Prevention

This section outlines the steps to mitigate and prevent the exploitation of CVE-2021-22864.

Immediate Steps to Take

Users of GitHub Enterprise Server should update their systems to version 3.0.3, 2.22.9, or 2.21.17 to patch the vulnerability and prevent potential attacks. Additionally, monitoring for suspicious activities and unauthorized changes in configuration settings is crucial.

Long-Term Security Practices

Implementing robust access controls, regular security audits, and educating users on secure configuration practices are essential for enhancing the overall security posture of GitHub Enterprise Server instances.

Patching and Updates

Regularly applying security patches released by GitHub, particularly those addressing remote code execution vulnerabilities, is critical to safeguarding GitHub Enterprise Server environments from potential threats.