CVE-2021-22870 : What You Need to Know

A path traversal vulnerability was identified in GitHub Pages builds on GitHub Enterprise Server that could allow an attacker to read system files. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.3 and was fixed in versions 3.0.19, 3.1.11, and 3.2.3. To exploit this vulnerability, an attacker would need permission to create and build a GitHub Pages site on the GitHub Enterprise Server instance. This vulnerability was reported via the GitHub Bug Bounty program.

Understanding CVE-2021-22870

This section provides insights into the impact, technical details, and mitigation strategies related to CVE-2021-22870.

What is CVE-2021-22870?

CVE-2021-22870 is a path traversal vulnerability in GitHub Enterprise Server's hosted Pages feature that allows unauthorized access to system files by exploiting build processes.

The Impact of CVE-2021-22870

This vulnerability could be exploited by attackers to read sensitive system files on GitHub Enterprise Server instances, potentially leading to unauthorized access to critical information.

Technical Details of CVE-2021-22870

Here are the technical specifics of CVE-2021-22870, including the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability in GitHub Enterprise Server allows attackers to read unauthorized system files through GitHub Pages builds, requiring permission to create and build Pages sites.

Affected Systems and Versions

GitHub Enterprise Server versions 3.0.19, 3.1.11, and 3.2.3 are affected by this vulnerability, while version 3.3 and above are patched against this threat.

Exploitation Mechanism

Exploiting CVE-2021-22870 involves leveraging the path traversal flaw in GitHub Pages builds to traverse directories and access sensitive files without proper authorization.

Mitigation and Prevention

Discover the immediate steps and long-term security practices to safeguard your systems against CVE-2021-22870.

Immediate Steps to Take

It is essential to update GitHub Enterprise Server to versions 3.0.19, 3.1.11, or 3.2.3 to mitigate the risks posed by this vulnerability. Additionally, restrict access permissions for creating and building GitHub Pages sites.

Long-Term Security Practices

Implement robust access control mechanisms, conduct regular security assessments, and monitor Page build activities to prevent path traversal attacks and unauthorized file access.

Patching and Updates

Stay informed about security patches and updates released by GitHub Enterprise Server to address existing vulnerabilities and strengthen system defenses.