CVE-2019-20143 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community Edition (CE) and Enterprise Edition (EE) 12.6. It has Incorrect Access Control.
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Analysis
by VulDB Data Team • 01/14/2020
The vulnerability identified as CVE-2019-20143 represents a critical access control flaw within GitLab Community Edition and Enterprise Edition versions up to 12.6. This issue stems from insufficient authorization checks that allow unauthorized users to access sensitive project resources and data. The flaw exists in the application's permission model where certain API endpoints and administrative functions do not properly validate user credentials or roles before granting access to protected resources. This vulnerability specifically affects the project-level access controls and can be exploited by malicious actors who have gained access to a regular user account or have bypassed initial authentication mechanisms. The root cause lies in the application's failure to implement proper role-based access control checks, which is a fundamental security principle that should prevent unauthorized access to system resources.
The technical implementation of this vulnerability manifests through improper validation of user permissions when accessing project-related endpoints. Attackers can leverage this weakness to escalate privileges and gain access to projects they should not be authorized to view or modify. The flaw typically occurs in scenarios where the application assumes that users with basic access rights can perform administrative functions or access sensitive data without proper verification. This misconfiguration creates a pathway for privilege escalation attacks where unauthenticated or low-privilege users can manipulate API calls to access restricted project information, including code repositories, issue trackers, and configuration settings. The vulnerability is particularly concerning because GitLab serves as a central platform for code management and collaboration, making it a prime target for attackers seeking to compromise development environments.
The operational impact of CVE-2019-20143 extends beyond simple data exposure, potentially enabling full system compromise through lateral movement and privilege escalation. Organizations using affected GitLab versions face significant risks including code theft, data manipulation, and potential backdoor installation through compromised project repositories. The vulnerability can be exploited to access sensitive information such as source code, configuration files, and user credentials stored within the platform. Security teams may experience false positives in their monitoring systems as attackers leverage this flaw to move undetected through the environment. The impact is particularly severe for organizations that rely heavily on GitLab for continuous integration and deployment pipelines, as attackers could potentially modify build scripts or access secrets stored in project configurations. This vulnerability also affects compliance requirements for organizations subject to regulatory frameworks that mandate strict access controls and audit trails.
Mitigation strategies for CVE-2019-20143 require immediate attention and should include upgrading to GitLab versions that have addressed this access control flaw. Organizations must implement comprehensive access control reviews and validate that all user permissions are properly enforced at the application level. The fix typically involves implementing proper authentication checks and ensuring that all API endpoints validate user credentials against appropriate authorization rules. Security teams should conduct thorough audits of project permissions and implement network segmentation to limit access to GitLab instances. Additionally, organizations should enable detailed logging and monitoring of access attempts to detect potential exploitation attempts. The remediation process must include verifying that role-based access controls are properly configured and that administrative functions require appropriate elevated privileges. Regular security assessments and penetration testing should be conducted to ensure that similar access control vulnerabilities do not exist in other parts of the GitLab deployment. This vulnerability aligns with CWE-284 which addresses improper access control issues, and may be mapped to ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting, demonstrating the multi-layered nature of the threat landscape this vulnerability creates.