CVE-2017-0920 in Community Edition
Summary
by MITRE
GitLab Community and Enterprise Editions before 10.1.6, 10.2.6, and 10.3.4 are vulnerable to an authorization bypass issue in the Projects::MergeRequests::CreationsController component resulting in an attacker to see every project name and their respective namespace on a GitLab instance.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability identified as CVE-2017-0920 represents a critical authorization bypass flaw within GitLab's access control mechanisms that affects multiple versions of both Community and Enterprise editions. This issue resides within the Projects::MergeRequests::CreationsController component, which governs the creation and management of merge requests in GitLab's distributed version control system. The flaw allows unauthenticated attackers to bypass normal access controls and gain visibility into all project names and their corresponding namespaces across the entire GitLab instance, effectively exposing sensitive organizational information about code repositories and their structural hierarchy.
The technical root cause of this vulnerability stems from improper access validation within the merge request creation controller, where the system fails to adequately verify user permissions before exposing project listing information. This authorization bypass occurs because the controller does not properly enforce authentication checks when processing requests for project data, allowing any remote attacker to obtain comprehensive knowledge of all projects hosted within the GitLab instance. The flaw specifically impacts the namespace and project name enumeration functionality, which should normally be restricted to authenticated users with appropriate access rights.
From an operational perspective, this vulnerability creates significant security implications for organizations relying on GitLab for code management and collaboration. Attackers can exploit this flaw to perform reconnaissance activities without requiring valid credentials, enabling them to map out the complete repository structure of a GitLab instance. This information disclosure can facilitate more sophisticated attacks by providing attackers with insights into project dependencies, code ownership patterns, and organizational structure. The exposure of namespace information particularly undermines the security of private repositories, as attackers can identify which projects contain sensitive code and potentially target them for further exploitation.
The vulnerability aligns with CWE-285, which addresses improper authorization within software systems, and can be categorized under the ATT&CK technique T1087.001 for account discovery and T1069.001 for credential access. Organizations using affected GitLab versions face increased risk of targeted attacks, as the exposed project information provides attackers with valuable intelligence for planning subsequent exploitation attempts. The impact extends beyond simple information disclosure, as this vulnerability can serve as a precursor to more serious attacks including privilege escalation, data exfiltration, and social engineering operations that leverage the discovered project relationships and organizational structure.
Organizations should immediately upgrade to GitLab versions 10.1.6, 10.2.6, or 10.3.4 to remediate this vulnerability, as these releases contain the necessary patches to enforce proper access controls within the merge request creation controller. Additionally, administrators should conduct comprehensive audits of their GitLab instances to ensure all users have appropriate access levels and that no unauthorized modifications have occurred. Network segmentation and monitoring should be enhanced to detect unusual access patterns that might indicate exploitation attempts, while security teams should review access logs for any evidence of unauthorized enumeration activities. The patch addresses the core authorization bypass issue by implementing proper authentication checks before exposing project information, thereby restoring the intended access control boundaries within GitLab's permission model.