CVE-2018-18642 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition before 11.2.7, 11.3.x before 11.3.8, and 11.4.x before 11.4.3. It has XSS.
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Analysis
by VulDB Data Team • 06/13/2023
This vulnerability represents a cross-site scripting flaw that affected GitLab installations across multiple version ranges including Community and Enterprise Editions. The issue stems from insufficient input validation and output encoding mechanisms within the GitLab application's web interface. Attackers could exploit this weakness by injecting malicious javascript code through specific input fields that were not properly sanitized before rendering user-provided content. The vulnerability impacts the core functionality of GitLab's web-based interface where user-generated content is displayed, potentially allowing unauthorized access to user sessions and data manipulation. This type of vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in software applications. The attack surface encompasses all user interactions within the GitLab platform that involve rendering user input, including issue descriptions, comments, commit messages, and project information fields. The vulnerability's exploitation requires minimal privileges and can be executed through standard web browser interactions, making it particularly dangerous in collaborative development environments where multiple users interact with shared repositories and projects.
The technical implementation of this XSS vulnerability occurs when user input containing malicious script tags is processed and rendered without proper HTML escaping or sanitization. This flaw allows attackers to inject javascript payloads that execute in the context of other users' browsers when they view affected content. The impact extends beyond simple script execution to potentially enable session hijacking, credential theft, and unauthorized actions within the GitLab environment. Attackers could leverage this vulnerability to escalate privileges, access sensitive project information, or manipulate repository contents. The vulnerability's presence in multiple release branches demonstrates a persistent flaw in GitLab's input validation mechanisms that required patching across different version lines. This particular vulnerability aligns with ATT&CK technique T1059.007 which covers scripting through web shells and similar injection techniques. The flaw represents a fundamental security gap in the application's defense-in-depth strategy, particularly concerning the handling of untrusted input within web interfaces.
Organizations utilizing GitLab must implement immediate remediation measures to address this vulnerability across all affected versions. The most effective mitigation involves applying the official security patches released by GitLab for versions 11.2.7, 11.3.8, and 11.4.3 respectively. System administrators should conduct comprehensive vulnerability assessments to identify any potentially compromised user sessions and implement additional monitoring for suspicious activities. The remediation process should include verifying that all user input fields are properly sanitized and that output encoding is consistently applied throughout the application. Organizations should also consider implementing web application firewalls and content security policies as additional protective measures. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in the application's codebase. The incident highlights the importance of maintaining up-to-date security practices and demonstrates how seemingly minor input validation flaws can create significant security risks in collaborative development platforms. Security teams should establish automated patch management processes to ensure timely application of security updates and prevent similar vulnerabilities from persisting in production environments.