CVE-2017-11438 in Community Edition
Summary
by MITRE
GitLab Community Edition (CE) and Enterprise Edition (EE) before 9.0.11, 9.1.8, 9.2.8 allow an authenticated user with the ability to create a group to add themselves to any project that is inside a subgroup.
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Analysis
by VulDB Data Team • 11/03/2019
This vulnerability exists in GitLab Community Edition and Enterprise Edition versions prior to 9.0.11, 9.1.8, and 9.2.8, representing a privilege escalation flaw that allows authenticated users to gain unauthorized access to projects within subgroups. The technical implementation contains a logic flaw in the group membership validation process where users with sufficient permissions to create groups can manipulate their access rights to include themselves in projects located within nested subgroup structures. This issue stems from inadequate access control checks that fail to properly validate whether a user has legitimate authorization to join projects in subgroups, particularly when those projects are nested within multiple levels of group hierarchy.
The operational impact of this vulnerability is significant as it enables malicious or compromised users to bypass intended access controls and gain unauthorized access to sensitive project data, code repositories, and associated resources within subgroup structures. Attackers can leverage this flaw to escalate their privileges from regular group members to project-level access, potentially leading to data exfiltration, code manipulation, or unauthorized modifications to critical infrastructure. The vulnerability specifically targets the group creation functionality and its integration with project membership systems, creating a pathway for unauthorized access that could affect organizations with complex multi-level group hierarchies.
From a cybersecurity perspective, this vulnerability aligns with CWE-285, which addresses improper authorization issues, and maps to ATT&CK technique T1078.004 for Valid Accounts and T1484.001 for Domain Policy Modification. The flaw demonstrates poor input validation and access control implementation that allows privilege escalation through legitimate system functions. Organizations utilizing GitLab with nested group structures face elevated risk as this vulnerability can be exploited by users who have been granted minimal permissions to create groups but not to access specific projects. The issue is particularly concerning in enterprise environments where strict access controls and separation of duties are critical for maintaining security boundaries and protecting sensitive information assets.
The recommended mitigation strategy involves upgrading to GitLab versions 9.0.11, 9.1.8, or 9.2.8, which contain the necessary patches to address the access control validation flaw. Organizations should also implement additional monitoring of group creation activities and membership modifications to detect anomalous behavior. Security teams should review existing group and project access controls to ensure proper segregation of duties and implement principle of least privilege configurations. Regular security assessments of GitLab installations should include verification of access control mechanisms and proper validation of user permissions within nested group hierarchies to prevent similar vulnerabilities from emerging in other system components.