CVE-2022-1783 in Community Edition
Summary
by MITRE • 06/06/2022
An issue has been discovered in GitLab CE/EE affecting all versions starting from 14.3 before 14.9.5, all versions starting from 14.10 before 14.10.4, all versions starting from 15.0 before 15.0.1. It may be possible for malicious group maintainers to add new members to a project within their group, through the REST API, even after their group owner enabled a setting to prevent members from being added to projects within that group.
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Analysis
by VulDB Data Team • 06/08/2022
This vulnerability in GitLab CE/EE represents a critical access control bypass that undermines the security configuration set by group owners. The flaw exists in the permission model implementation where group maintainers can circumvent restrictions that should prevent them from adding members to projects within their group. This issue affects versions from 14.3 through 14.9.4, 14.10 through 14.10.3, and 15.0 through 15.0.0, demonstrating a widespread impact across multiple release lines. The vulnerability is categorized under CWE-668, which specifically addresses "Exposure of Resource to Wrong Sphere," indicating that the system grants inappropriate access to resources through a flawed access control mechanism.
The technical implementation of this vulnerability stems from a logic error in the REST API endpoint validation process. When group owners enable the restriction setting to prevent member additions to projects within their group, the system fails to properly validate the permissions of group maintainers who attempt to use the API for member management. This allows malicious actors with group maintainer privileges to bypass the intended access controls by directly invoking the REST API endpoints. The flaw essentially creates a path where elevated privileges can be leveraged to perform unauthorized actions, even when the system's configuration explicitly prohibits such behavior. The vulnerability is particularly concerning because it operates at the API level, meaning that automated attacks can exploit this without requiring direct user interface interaction.
The operational impact of this vulnerability extends beyond simple unauthorized access to project membership management. Group maintainers who exploit this vulnerability can effectively undermine the security posture of entire groups and organizations by adding unauthorized users to sensitive projects. This creates potential pathways for privilege escalation, data exfiltration, and unauthorized code modifications. The vulnerability also impacts audit and compliance requirements since it allows for membership changes that bypass documented security policies and procedures. Organizations using GitLab for software development, code review, and collaboration may find their access control mechanisms compromised, potentially leading to unauthorized access to source code repositories and associated sensitive data. This vulnerability directly aligns with ATT&CK technique T1078.004, which covers "Valid Accounts: Cloud Accounts," as it allows for unauthorized access through legitimate account privileges.
Organizations should immediately implement mitigations including upgrading to the patched versions 14.9.5, 14.10.4, and 15.0.1 respectively. Additionally, administrators should review and audit existing group membership configurations to identify any unauthorized additions that may have occurred. The implementation of additional monitoring around REST API calls for membership management operations can help detect potential exploitation attempts. Security teams should also consider implementing just-in-time access controls and regular permission reviews to minimize the impact of such vulnerabilities. The fix addresses the core logic error in the API endpoint validation and ensures that group owner configuration settings are properly enforced regardless of the user's role within the group structure.