CVE-2022-23733 in GitHub
Summary
by MITRE • 08/02/2022
A stored XSS vulnerability was identified in GitHub Enterprise Server that allowed the injection of arbitrary attributes. This injection was blocked by Github's Content Security Policy (CSP). This vulnerability affected all versions of GitHub Enterprise Server prior to 3.6 and was fixed in versions 3.3.11, 3.4.6 and 3.5.3. This vulnerability was reported via the GitHub Bug Bounty program.
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Analysis
by VulDB Data Team • 08/30/2022
The stored cross-site scripting vulnerability identified as CVE-2022-23733 represents a critical security flaw in GitHub Enterprise Server that emerged from the intersection of web application security and content filtering mechanisms. This vulnerability specifically targeted the server's handling of user input within stored data contexts, creating a pathway for malicious actors to inject arbitrary attributes into the system's data storage. The flaw existed in all versions prior to the security patches released in versions 3.3.11, 3.4.6, and 3.5.3, demonstrating how even well-established security platforms can harbor persistent weaknesses in their input validation and sanitization processes. The vulnerability was responsibly disclosed through GitHub's official bug bounty program, highlighting the importance of coordinated disclosure in maintaining secure software ecosystems and the collaborative nature of modern vulnerability management.
The technical implementation of this stored XSS vulnerability stemmed from insufficient validation of user-supplied attributes within GitHub Enterprise Server's data processing pipeline. When legitimate users entered content containing potentially malicious attributes, the system failed to properly sanitize these inputs before storing them in the database. This oversight created a scenario where subsequent requests could execute the stored malicious code within the context of other users' browsers, leveraging the trust relationship between the server and its clients. The vulnerability's classification as a stored XSS attack aligns with CWE-79, which specifically addresses cross-site scripting flaws where malicious scripts are stored on the server and subsequently executed when other users access the compromised content. The fact that the injection was blocked by Content Security Policy demonstrates that while the system had protective mechanisms in place, the fundamental flaw in input validation allowed the malicious attributes to persist beyond the initial sanitization phase.
The operational impact of CVE-2022-23733 extended beyond simple data corruption or unauthorized access, potentially enabling attackers to execute arbitrary code within the browser contexts of other users. This capability could facilitate session hijacking, credential theft, or redirection to malicious sites, particularly when targets were administrators or users with elevated privileges within the enterprise environment. The vulnerability's presence across multiple versions of GitHub Enterprise Server created widespread exposure, as organizations using any version prior to the patched releases remained at risk. The attack vector likely involved users with sufficient privileges to create or modify content within the system, making the exploitation particularly concerning in environments where multiple users interact with shared repositories and collaborative features. Security professionals needed to assess their entire GitHub Enterprise Server deployment to identify affected systems and implement immediate remediation measures.
The mitigation strategy for CVE-2022-23733 required immediate deployment of the vendor-provided patches across all affected versions of GitHub Enterprise Server. Organizations should have conducted comprehensive vulnerability assessments to identify systems running unsupported versions and prioritized the upgrade process to versions 3.3.11, 3.4.6, or 3.5.3. Additionally, security teams needed to implement enhanced monitoring of user-generated content and conduct regular audits of stored data to detect any potential exploitation attempts. The vulnerability's resolution through the official patching process aligns with ATT&CK technique T1548.002, which covers privilege escalation through application sandbox escaping, though in this case the issue was more accurately categorized as a data validation flaw. Organizations should have also reviewed their incident response procedures to ensure proper handling of such vulnerabilities and established communication protocols for reporting similar issues in their own systems or third-party applications, as the vulnerability demonstrated how even established platforms can harbor critical flaws that require continuous security assessment and patch management processes.