CVE-2018-20491 in Enterprise Edition
Summary
by MITRE
An issue was discovered in GitLab Enterprise Edition 11.3.x and 11.4.x before 11.4.13, 11.5.x before 11.5.6, and 11.6.x before 11.6.1. It allows XSS.
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Analysis
by VulDB Data Team • 03/18/2024
This vulnerability represents a cross-site scripting flaw that affected multiple versions of GitLab Enterprise Edition, specifically targeting releases from 11.3.x through 11.6.x prior to their respective security patches. The issue stems from inadequate input validation and output encoding mechanisms within the application's web interface, allowing malicious actors to inject arbitrary JavaScript code into web pages viewed by other users. The vulnerability exists in the way GitLab handles user-provided data when rendering project information, issue descriptions, and other interactive elements within the web application's user interface.
The technical implementation of this XSS vulnerability occurs through improper sanitization of user input in various web application components. Attackers can exploit this by creating malicious project names, issue titles, or descriptions containing JavaScript payloads that execute in the context of other users' browsers when they view affected content. The flaw leverages the browser's trust in the application's own content, allowing attackers to bypass standard security mechanisms that protect against malicious script execution. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a reflected XSS attack vector where malicious input is immediately reflected back to users without proper sanitization.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to hijack user sessions, steal sensitive authentication tokens, redirect users to malicious websites, or perform unauthorized actions within the GitLab application on behalf of legitimate users. The vulnerability affects all users within the affected GitLab instances, making it particularly dangerous in enterprise environments where GitLab serves as a central collaboration platform for development teams. Users with elevated privileges could potentially escalate their access and compromise entire repositories, leading to data breaches or unauthorized code modifications. The attack surface is significant given that GitLab is commonly used for managing source code, issue tracking, and collaboration, making every project and issue potentially exploitable.
Mitigation strategies for this vulnerability require immediate patching of affected GitLab instances to versions 11.4.13, 11.5.6, or 11.6.1 respectively, which contain the necessary security fixes. Organizations should also implement additional defensive measures including input validation at multiple layers, content security policies to restrict script execution, and regular security audits of web application components. The vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing proper security controls as outlined in the ATT&CK framework's application layer techniques. Security teams should also consider implementing web application firewalls and monitoring for suspicious user behavior patterns that might indicate exploitation attempts. Regular security training for developers on secure coding practices and input validation techniques remains essential to prevent similar vulnerabilities in future releases.