CVE-2022-3375 in GitLab
Summary
by MITRE • 04/05/2023
An issue has been discovered in GitLab affecting all versions starting from 11.10 before 15.8.5, all versions starting from 15.9 before 15.9.4, all versions starting from 15.10 before 15.10.1. It was possible to disclose the branch names when attacker has a fork of a project that was switched to private.
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Analysis
by VulDB Data Team • 04/23/2023
This vulnerability in GitLab represents a critical information disclosure flaw that undermines the privacy controls of private repositories. The issue affects multiple version ranges including 11.10 through 15.8.4, 15.9 through 15.9.3, and 15.10 through 15.10.0, demonstrating a prolonged period of exposure across the software lifecycle. The vulnerability specifically targets the access control mechanisms that should prevent unauthorized users from discovering branch names within private projects. When an attacker possesses a fork of a project that has been switched to private status, they can still enumerate and disclose branch names that should otherwise remain hidden from unauthorized parties.
The technical root cause of this vulnerability lies in the improper validation of access permissions within GitLab's branch enumeration mechanisms. When a project transitions from public to private status, the system should enforce strict access controls that prevent any unauthorized disclosure of repository metadata, including branch names. However, the flaw allows attackers with access to a project fork to bypass these access controls and retrieve branch information that should be restricted to authorized users only. This represents a failure in the principle of least privilege and demonstrates a critical breakdown in the access control model that GitLab employs for repository management.
The operational impact of this vulnerability extends beyond simple information disclosure, as branch names can reveal significant information about project structure, development activities, and potential security implications. Attackers can use disclosed branch names to identify development workflows, locate sensitive code patterns, and potentially discover vulnerabilities in less stable branches. This information can be leveraged for more sophisticated attacks including targeted exploitation of development environments or identification of security gaps in the project's codebase. The vulnerability particularly affects organizations that rely on GitLab's private repository features for protecting sensitive development work, as it undermines the fundamental security assumptions of private project access control.
This vulnerability maps to CWE-200, which describes "Information Exposure" and specifically addresses the inappropriate exposure of information that should be restricted. The attack vector aligns with ATT&CK technique T1213.002, "Access to Information through Shell," as it involves unauthorized access to repository information through the GitLab interface. Organizations should implement immediate mitigations including upgrading to the patched versions 15.8.5, 15.9.4, or 15.10.1 respectively, and conducting thorough security audits of their GitLab instances. Additional defensive measures include implementing stricter access controls for project forks, monitoring for unauthorized access attempts, and ensuring that all project transitions from public to private status are properly enforced. The vulnerability highlights the importance of comprehensive access control testing and the need for regular security assessments of repository management systems to prevent such information disclosure scenarios.