CVE-2023-3949 in GitLab
Summary
by MITRE • 12/01/2023
An issue has been discovered in GitLab affecting all versions starting from 11.3 before 16.4.3, all versions starting from 16.5 before 16.5.3, all versions starting from 16.6 before 16.6.1. It was possible for unauthorized users to view a public projects' release descriptions via an atom endpoint when release access on the public was set to only project members.
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Analysis
by VulDB Data Team • 10/03/2024
This vulnerability in GitLab represents a critical access control flaw that undermines the intended security boundaries of public project configurations. The issue affects a broad range of GitLab versions including 11.3 through 16.4.2, 16.5 through 16.5.2, and 16.6 through 16.6.0, demonstrating a long-standing weakness in the platform's authorization mechanisms. The vulnerability specifically targets the atom feed endpoint that serves release descriptions, creating an unexpected information disclosure channel that bypasses normal access controls.
The technical flaw stems from improper validation of access permissions when generating atom feeds for project releases. When a project is configured with release access restricted to project members only, the atom endpoint still serves release descriptions to unauthorized users who can access the public project. This represents a classic case of insufficient authorization checking where the system fails to properly verify user credentials against the project's release access policies before serving sensitive content. The vulnerability is classified under CWE-284 as an improper access control issue, specifically involving inadequate permission checks for resource access.
The operational impact of this vulnerability is significant as it allows unauthorized users to obtain sensitive release information that might include security advisories, version details, or other potentially sensitive metadata about software releases. Attackers could leverage this information to identify vulnerable versions, plan targeted attacks against specific releases, or gather intelligence for further exploitation attempts. The vulnerability affects the core GitLab functionality related to release management and project visibility, potentially exposing release notes, changelogs, and other metadata that should remain restricted to authorized personnel.
This issue aligns with ATT&CK technique T1068 which involves the exploitation of legitimate credentials and access control mechanisms to gain unauthorized access to information. The vulnerability essentially creates a backdoor through which unauthorized users can bypass normal access controls to retrieve information that should be restricted. Organizations using GitLab in environments where release information might contain sensitive details about software versions, security patches, or development progress could face serious consequences from this exposure. The impact is particularly concerning for enterprises that maintain strict access controls over their software release information and rely on GitLab for version control and release management.
The recommended mitigations include immediate upgrade to the patched versions 16.4.3, 16.5.3, or 16.6.1 respectively, along with verification of existing project configurations to ensure that release access controls are properly enforced. Administrators should also review access logs to identify any unauthorized access attempts that may have occurred during the vulnerable period. Additionally, implementing network-level monitoring for unusual access patterns to atom feeds and release endpoints can help detect potential exploitation attempts. Organizations should also consider implementing additional access controls at the network level to further restrict access to sensitive endpoints, particularly in environments where information disclosure could pose significant security risks.