CVE-2019-6960 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition 9.x, 10.x, and 11.x before 11.5.8, 11.6.x before 11.6.6, and 11.7.x before 11.7.1. It has Incorrect Access Control. Access to the internal wiki is permitted when an external wiki service is enabled.
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Analysis
by VulDB Data Team • 12/18/2023
The vulnerability CVE-2019-6960 represents a critical access control flaw in GitLab's wiki functionality that affects multiple versions across the 9.x, 10.x, and 11.x release lines. This issue stems from improper authorization checks within the GitLab platform's internal wiki system, creating a scenario where unauthorized users can gain access to internal wiki content even when external wiki services have been enabled. The flaw exists in the platform's permission model and specifically impacts the boundary between internal and external wiki access controls. According to CWE-284, this vulnerability falls under improper access control, where the system fails to properly enforce access restrictions that should prevent unauthorized access to internal resources. The vulnerability's impact is particularly concerning because it allows for privilege escalation through the wiki access mechanism, potentially exposing sensitive internal documentation and project information.
The technical implementation of this flaw occurs within GitLab's wiki service architecture where the system does not correctly validate access permissions when external wiki services are configured. When administrators enable external wiki services, the platform should restrict internal wiki access to authorized users only, but due to this vulnerability, the access control logic fails to enforce these restrictions properly. This creates a situation where users who should only have access to external wiki content can potentially access internal wiki resources, bypassing the intended security boundaries. The flaw demonstrates a classic case of insufficient authorization checks as defined by ATT&CK technique T1078.004, where adversaries can exploit weak access controls to gain unauthorized access to internal systems. The vulnerability exists because the platform's wiki access control logic does not properly distinguish between external and internal wiki access, allowing cross-contamination of access permissions between these distinct service types.
The operational impact of CVE-2019-6960 extends beyond simple information disclosure, as it creates potential for data leakage and unauthorized modification of internal wiki content. Organizations using GitLab in environments where internal wiki content contains sensitive project documentation, security policies, or development notes face significant risk from this vulnerability. The flaw could enable malicious actors or compromised users to access confidential information that should only be available to authorized personnel within the organization. This access could potentially lead to further exploitation opportunities, as internal wiki content often contains technical details, system configurations, or development processes that could aid in more sophisticated attacks. The vulnerability affects all GitLab installations running the affected versions, making it particularly dangerous for organizations that have not yet patched their systems. According to industry best practices for secure software development, this type of access control flaw should be addressed through proper input validation, explicit access control checks, and comprehensive testing of permission boundaries.
Organizations should immediately implement mitigations including upgrading to the patched versions of GitLab where this vulnerability has been addressed. The recommended remediation involves applying the official patches released by GitLab for versions 11.5.8, 11.6.6, and 11.7.1, which contain fixes for the access control logic. Additionally, administrators should review their current wiki configurations and disable external wiki services if internal wiki access is required for sensitive projects. Security teams should conduct comprehensive access control audits to identify any potential unauthorized access that may have occurred due to this vulnerability. The mitigation strategy should also include monitoring for unusual wiki access patterns and implementing additional logging controls to detect potential exploitation attempts. Organizations should consider implementing network segmentation and additional authentication layers to reduce the attack surface and limit potential impact if the vulnerability is exploited. The fix for this vulnerability demonstrates the importance of proper access control implementation and the need for thorough testing of permission boundaries in collaborative development platforms.