CVE-2019-5487 in Enterprise Edition
Summary
by MITRE
An improper access control vulnerability exists in Gitlab EE <v12.3.3, <v12.2.7, & <v12.1.13 that allowed the group search feature with Elasticsearch to return private code, merge requests and commits.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability CVE-2019-5487 represents a critical access control flaw in GitLab Enterprise Edition that affected multiple versions prior to specific patch releases. This issue exploited a weakness in the group search functionality when Elasticsearch was enabled, creating a situation where unauthorized users could gain access to sensitive private resources within the platform. The vulnerability specifically targeted the search feature's ability to return private code repositories, merge requests, and commit histories, effectively undermining the fundamental security model that separates public and private content within GitLab's access control system.
The technical root cause of this vulnerability stems from inadequate authorization checks within the Elasticsearch search implementation for group-level queries. When users performed searches within GitLab's group context, the system failed to properly validate whether the requesting user had appropriate permissions to access the specific resources being returned in the search results. This flaw allowed authenticated users to bypass normal access controls and retrieve information that should have been restricted to specific group members or administrators. The issue manifests particularly when Elasticsearch is configured as the search backend, making it a targeted vulnerability for organizations that utilize this feature for enhanced search performance.
The operational impact of CVE-2019-5487 extends beyond simple information disclosure, as it creates potential for data exfiltration and unauthorized code access that could compromise intellectual property and sensitive development information. Attackers could leverage this vulnerability to discover private repositories, access confidential merge requests containing sensitive code changes, and retrieve commit histories that might reveal development timelines, security patches, or implementation details. Organizations using GitLab's group search functionality with Elasticsearch were particularly at risk, as the vulnerability could be exploited by any authenticated user with access to the search interface, potentially affecting thousands of private projects across different groups and organizations.
This vulnerability aligns with CWE-284, which describes improper access control, and maps to ATT&CK technique T1083, which covers directory and file system discovery. The flaw demonstrates how search functionality can become a vector for privilege escalation when proper authorization checks are missing from the implementation. Organizations should implement immediate mitigation strategies including updating to patched versions of GitLab, reviewing Elasticsearch configuration settings, and implementing additional monitoring for unusual search activity patterns. The vulnerability underscores the importance of comprehensive access control validation in search and indexing systems, particularly when dealing with hierarchical data structures and user permissions that vary across different resource types within software development platforms.
The remediation approach requires organizations to upgrade to GitLab versions 12.3.3, 12.2.7, or 12.1.13, depending on their current installation, while also conducting thorough security reviews of their Elasticsearch configurations. Additionally, administrators should implement enhanced logging and monitoring to detect potential exploitation attempts, and consider temporarily disabling group search functionality with Elasticsearch until comprehensive security assessments are complete. This vulnerability serves as a reminder of the critical importance of validating access controls across all platform features, particularly those that aggregate and present information from multiple sources.