CVE-2019-20145 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community Edition (CE) and Enterprise Edition (EE) 11.4 through 12.6.1. It has Incorrect Access Control.
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Analysis
by VulDB Data Team • 01/14/2020
This vulnerability resides within GitLab's access control mechanisms affecting versions 11.4 through 12.6.1 of both Community and Enterprise editions. The flaw represents a critical authorization bypass that allows unauthorized users to access private project resources and data that should be restricted to authorized personnel only. The vulnerability stems from insufficient validation of user permissions when accessing certain project-related endpoints, creating a pathway for malicious actors to exploit the system's trust model. This issue directly violates the fundamental principle of least privilege and can lead to unauthorized data exposure, manipulation, and potential escalation of privileges within the GitLab environment.
The technical implementation of this access control flaw manifests in how GitLab validates user permissions when processing API requests and web interface interactions. Attackers can leverage this vulnerability by crafting specific requests that bypass normal permission checks, allowing them to view private repositories, access confidential code, examine project settings, and potentially manipulate project data. The vulnerability affects the core authentication and authorization subsystems, specifically targeting the way GitLab determines whether a user has sufficient privileges to perform certain operations. This weakness aligns with CWE-285, which addresses improper authorization issues in software systems, and represents a classic case of insufficient access control validation that enables privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple data exposure, potentially enabling comprehensive system compromise and data exfiltration. Organizations using affected GitLab versions face significant risk of intellectual property theft, code leaks, and unauthorized modifications to source code repositories. The vulnerability can be exploited by both external attackers and internal threat actors who may have gained initial access through other means. Successful exploitation allows attackers to gain access to sensitive project information, including confidential code, issue trackers, merge requests, and project management data. This can result in severe business disruption, regulatory compliance violations, and potential legal consequences. The vulnerability's impact is particularly concerning in enterprise environments where GitLab serves as a central code repository and collaboration platform, making it a prime target for cybercriminals seeking to access valuable source code assets.
Mitigation strategies for this vulnerability require immediate action including upgrading to GitLab versions 12.6.2 or later where the access control flaw has been addressed. Organizations should also implement network-level controls and monitoring to detect suspicious access patterns that may indicate exploitation attempts. Security teams should conduct comprehensive audits of user permissions and access logs to identify any potential unauthorized access that may have occurred during the vulnerability window. Additional defensive measures include implementing multi-factor authentication, regularly reviewing access controls, and establishing automated monitoring for anomalous API usage patterns. The fix implemented by GitLab addresses the root cause by strengthening permission validation checks and ensuring proper access control enforcement throughout the application's core components. Organizations should also consider implementing security awareness training for developers and administrators to prevent similar issues in custom applications that may interact with GitLab's API endpoints. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing robust access control mechanisms in collaborative development environments.