CVE-2019-6791 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition before 11.5.8, 11.6.x before 11.6.6, and 11.7.x before 11.7.1. It has Incorrect Access Control (issue 3 of 3). When a project with visibility more permissive than the target group is imported, it will retain its prior visibility.
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Analysis
by VulDB Data Team • 08/17/2020
The vulnerability described in CVE-2019-6791 represents a critical access control flaw within GitLab's permission management system that affects multiple versions of the platform. This issue manifests when projects are imported into groups with more restrictive visibility settings than the original project, creating a scenario where the imported project maintains its previous visibility level instead of adopting the more restrictive group settings. The flaw falls under the category of incorrect access control as defined by CWE-284, which specifically addresses inadequate access control mechanisms that allow unauthorized users to access resources they should not be permitted to access.
The technical implementation of this vulnerability stems from GitLab's import functionality failing to properly enforce visibility restrictions during project migration processes. When administrators import projects into groups, the system should automatically adjust project visibility settings to align with the group's more restrictive permissions. However, the bug causes the imported project to retain its original visibility configuration regardless of the target group's settings. This creates a situation where a project that was originally public or internal might be imported into a private group while maintaining its public visibility, effectively bypassing the intended access controls.
The operational impact of this vulnerability is significant as it undermines the fundamental security model of GitLab's permission system. An attacker or unauthorized user could potentially exploit this flaw to gain access to sensitive project information that should have been restricted to specific group members. This scenario becomes particularly dangerous in enterprise environments where projects contain confidential code, intellectual property, or sensitive data that should only be accessible to authorized personnel within specific teams or departments. The vulnerability essentially creates a backdoor that allows information to flow from more permissive to less permissive contexts, violating the principle of least privilege.
Organizations using affected GitLab versions face substantial risk of unauthorized data exposure and potential compliance violations. The flaw could enable malicious actors to discover and access projects that should be hidden from certain users or groups, potentially leading to intellectual property theft, security breaches, or regulatory non-compliance. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and legitimate credentials, as it allows unauthorized access through legitimate import functionality that should have enforced proper access controls. The impact extends beyond simple information disclosure to potentially enable further exploitation through the discovery of sensitive project configurations, code repositories, or development artifacts.
The recommended mitigation strategy involves upgrading to GitLab versions 11.5.8, 11.6.6, or 11.7.1, which contain the necessary patches to address the access control flaw. Organizations should also conduct thorough audits of their existing projects to identify any imported projects that may have retained incorrect visibility settings. Additionally, implementing regular access control reviews and monitoring import activities can help detect potential exploitation attempts. Security teams should consider disabling project import functionality temporarily during the upgrade process and ensure that proper testing is performed in staging environments before applying patches to production systems. The fix implemented in the patched versions ensures that project visibility settings are properly enforced during import operations, aligning with industry best practices for access control management and authorization enforcement.