CVE-2018-16976 in gitolite
Summary
by MITRE
Gitolite before 3.6.9 does not (in certain configurations involving @all or a regex) properly restrict access to a Git repository that is in the process of being migrated until the full set of migration steps has been completed. This can allow valid users to obtain unintended access.
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Analysis
by VulDB Data Team • 05/16/2023
Gitolite is a powerful access control system for git repositories that provides fine-grained permissions management for multiple users and groups. The vulnerability CVE-2018-16976 affects versions prior to 3.6.9 and represents a critical access control flaw that can lead to unauthorized data exposure during repository migration processes. This issue specifically manifests when certain configurations involving the @all group or regular expressions are used in conjunction with repository migration operations, creating a window of opportunity for privilege escalation.
The technical flaw stems from improper access validation during the repository migration lifecycle. When a repository is being migrated and the migration process has not yet completed fully, Gitolite fails to properly enforce access restrictions that should prevent users from accessing repository contents. This occurs particularly in configurations where the @all group is used or when regular expressions are employed in access control rules. The vulnerability exists because Gitolite does not adequately distinguish between legitimate access requests during migration and potentially unauthorized access attempts, allowing valid users to bypass intended access controls.
The operational impact of this vulnerability is significant as it can lead to data leakage and unauthorized access to sensitive repository contents during what should be a controlled migration process. Attackers could potentially exploit this vulnerability to access repository data that they should not have permission to view, particularly in environments where repository migration is performed regularly or where complex access control rules involving @all or regex patterns are in use. The risk is compounded because the vulnerability occurs during migration operations when administrators might be less vigilant about monitoring access patterns.
This vulnerability aligns with CWE-284 (Improper Access Control) and can be mapped to ATT&CK technique T1078 (Valid Accounts) as it exploits legitimate user accounts to gain unauthorized access. Organizations using Gitolite with complex access control configurations involving @all or regex patterns should immediately upgrade to version 3.6.9 or later. The recommended mitigation includes implementing proper access control validation during migration operations, ensuring that repository access is properly restricted until migration completion, and conducting regular security assessments of access control configurations. Additionally, administrators should review and simplify access control rules where possible to reduce the attack surface and implement monitoring for unusual access patterns during migration operations.