CVE-2018-20498 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
The vulnerability identified as CVE-2018-20498 represents a critical access control flaw affecting GitLab Community and Enterprise Edition installations across multiple version streams. This issue stems from inadequate authorization checks within the GitLab platform's permission system, allowing unauthorized users to bypass normal access controls and potentially gain elevated privileges. The vulnerability specifically impacts versions prior to 11.4.13, 11.5.6, and 11.6.1, indicating a widespread concern affecting the majority of GitLab deployments during that timeframe. The flaw manifests in the platform's inability to properly validate user permissions when accessing certain resources, creating a pathway for malicious actors to exploit the system's trust model.
The technical implementation of this access control vulnerability allows attackers to manipulate the system's authorization logic through crafted requests or by exploiting specific API endpoints that do not properly verify user credentials or role-based access controls. This type of flaw typically falls under CWE-284 which specifically addresses improper access control mechanisms in software systems. The vulnerability's exploitation potential is significant as it can enable unauthorized users to access private repositories, modify project settings, or potentially escalate their privileges within the GitLab environment. The flaw operates at the application layer where the platform's authentication and authorization components fail to properly enforce security boundaries between different user roles and permissions.
From an operational perspective, this vulnerability creates substantial risk for organizations relying on GitLab for code management and collaboration. The impact extends beyond simple unauthorized access to include potential data breaches, code tampering, and compromise of sensitive development artifacts. Attackers could leverage this flaw to gain access to private projects, view confidential source code, or manipulate repository configurations without proper authorization. The vulnerability's presence in multiple release streams suggests that organizations running any of the affected versions face immediate security risk, as the flaw affects core platform functionality rather than isolated components. This type of access control failure directly maps to ATT&CK technique T1078 which covers valid accounts and legitimate credentials for unauthorized access to systems.
Organizations should implement immediate mitigation strategies including upgrading to patched versions 11.4.13, 11.5.6, or 11.6.1 depending on their current deployment. Additional protective measures include implementing network-level restrictions, monitoring access logs for suspicious activities, and conducting thorough permission reviews to identify any unauthorized access that may have occurred during the vulnerable period. The vulnerability demonstrates the critical importance of proper access control implementation and highlights the need for regular security assessments of authentication systems. Organizations should also consider implementing additional security controls such as multi-factor authentication and regular security audits to prevent exploitation of similar vulnerabilities in the future.