CVE-2022-46256 in GitHub
Summary
by MITRE • 12/14/2022
A path traversal vulnerability was identified in GitHub Enterprise Server that allowed remote code execution when building a GitHub Pages site. To exploit this vulnerability, an attacker would need permission to create and build a GitHub Pages site on the instance. This vulnerability was fixed in versions 3.3.17, 3.4.12, 3.5.9, 3.6.5 and 3.7.2. This vulnerability was reported via the GitHub Bug Bounty program.
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Analysis
by VulDB Data Team • 01/12/2023
This vulnerability represents a critical path traversal flaw in GitHub Enterprise Server that enabled remote code execution through the GitHub Pages build process. The security issue manifested when users with sufficient privileges could manipulate file paths during site generation, allowing arbitrary file access and modification. The vulnerability specifically targeted the way GitHub Enterprise Server handled file system operations during Pages site construction, creating an opportunity for attackers to bypass normal access controls and execute malicious code on the underlying system.
The technical implementation of this vulnerability stems from inadequate input validation and path sanitization within the Pages build pipeline. Attackers could craft malicious file paths that would be processed by the server without proper authorization checks, potentially allowing them to traverse directories and access sensitive system files. This type of flaw aligns with CWE-22 Path Traversal vulnerability classification, where insufficient controls over file system access enable attackers to manipulate file paths and gain unauthorized access to system resources. The vulnerability's exploitation required legitimate user permissions to create and build Pages sites, making it a privilege escalation issue rather than a pure remote code execution vector.
The operational impact of this vulnerability was significant for organizations relying on GitHub Enterprise Server for their development workflows. The ability to execute arbitrary code on the server could lead to complete system compromise, data exfiltration, and persistent backdoors. Attackers could potentially access source code repositories, user credentials, and other sensitive information stored on the enterprise server. The vulnerability affected multiple release versions including 3.3.17, 3.4.12, 3.5.9, 3.6.5, and 3.7.2, indicating a widespread issue that required immediate patching across different server versions. Organizations using GitHub Enterprise Server needed to prioritize this vulnerability due to its potential for severe data breaches and system compromise.
Mitigation strategies for this vulnerability centered on immediate patching of affected server versions to prevent exploitation. Organizations should have implemented comprehensive monitoring for unauthorized Pages site creation activities and established strict access controls for repository permissions. The fix involved strengthening input validation and path handling within the Pages build process, ensuring that all file system operations properly sanitized user-supplied paths. Security teams should have conducted thorough vulnerability assessments of their GitHub Enterprise installations and reviewed access controls to prevent unauthorized users from creating malicious Pages sites. This vulnerability highlights the importance of proper input validation in web applications and the need for continuous security monitoring of development platforms. The fix aligns with ATT&CK technique T1059.001 Command and Scripting Interpreter where attackers could potentially execute commands through the compromised system, making early patching essential for preventing exploitation.
The vulnerability was responsibly disclosed through GitHub's bug bounty program, demonstrating the effectiveness of coordinated disclosure in addressing security issues. This approach allowed GitHub to develop and release patches before public disclosure, minimizing the window of opportunity for malicious actors. Organizations should maintain active participation in bug bounty programs and ensure their security teams are prepared to respond quickly to vulnerability disclosures. The incident underscores the critical importance of maintaining up-to-date security patches and implementing robust access controls for development platforms. Regular security assessments and monitoring of system logs for suspicious Pages site creation activities should be standard practice for enterprise environments using GitHub Enterprise Server.