CVE-2018-20493 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition before 11.4.13, 11.5.x before 11.5.6, and 11.6.x before 11.6.1. It has Incorrect Access Control.
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Analysis
by VulDB Data Team • 03/18/2024
This vulnerability represents a critical access control flaw in GitLab's authentication and authorization mechanisms that affected multiple versions of the platform. The issue stems from insufficient validation of user permissions within the application's core access control system, allowing authenticated users to bypass intended security restrictions and gain unauthorized access to resources they should not be able to view or modify. The vulnerability specifically impacts GitLab Community and Enterprise Edition installations running versions prior to the mentioned patches, creating a significant risk for organizations relying on the platform for code management and collaboration. Security researchers identified that the flaw existed in the way GitLab handled permission checks for certain project and group operations, particularly when users attempted to access specific resources within the application's interface.
The technical implementation of this access control vulnerability manifests through improper validation of user roles and permissions within GitLab's backend systems. Attackers could exploit this weakness by crafting specific requests that would circumvent the normal authorization checks, effectively allowing them to view private projects, access restricted information, and potentially modify resources they should not have access to based on their assigned roles. The flaw likely resides in the application's permission validation logic where user access rights are not properly verified before granting access to sensitive functionality or data. This type of vulnerability falls under the CWE-285 category of Improper Authorization, which specifically addresses issues where the application fails to properly enforce access controls for authenticated users. The vulnerability's impact extends beyond simple information disclosure as it could enable privilege escalation and unauthorized modifications to code repositories and project configurations.
The operational impact of this vulnerability poses significant risks to organizations utilizing GitLab for their software development workflows and version control needs. Attackers who successfully exploit this flaw could gain access to sensitive source code repositories, confidential project information, and potentially compromise the integrity of development processes. The vulnerability particularly affects organizations that rely heavily on GitLab's group and project management features, where access control is paramount for maintaining security boundaries between different teams and projects. In enterprise environments, this could lead to unauthorized access to proprietary code, exposure of security-sensitive configurations, and potential data breaches that could affect intellectual property and customer information. The vulnerability's persistence across multiple minor versions indicates a fundamental flaw in the platform's access control implementation that required immediate patching to prevent exploitation. Organizations using GitLab in production environments faced a critical security risk that could have been exploited by both internal malicious actors and external threat groups targeting code repositories.
Mitigation strategies for this vulnerability require immediate deployment of the patched versions released by GitLab, specifically versions 11.4.13, 11.5.6, and 11.6.1, which contain the necessary fixes to address the access control flaw. System administrators should conduct thorough security assessments of their GitLab installations to identify any potential exploitation attempts and implement monitoring for suspicious access patterns that might indicate exploitation of this vulnerability. The patch addresses the root cause by strengthening the permission validation logic and ensuring proper enforcement of access controls for all user interactions within the platform. Organizations should also consider implementing additional security measures such as network segmentation, enhanced logging and monitoring, and regular security audits of their GitLab configurations to prevent similar issues from occurring. This vulnerability aligns with ATT&CK technique T1078.004 which covers Valid Accounts and T1566.001 which covers Phishing, as attackers could potentially leverage compromised accounts to exploit this access control weakness. The incident highlights the importance of maintaining up-to-date software security practices and demonstrates how access control vulnerabilities can have far-reaching consequences in development environments where code repositories contain sensitive information and intellectual property assets.