CVE-2019-6797 in Enterprise Edition
Summary
by MITRE
An information disclosure issue was discovered in GitLab Enterprise Edition before 11.5.8, 11.6.x before 11.6.6, and 11.7.x before 11.7.1. The GitHub token used in CI/CD for External Repos was being leaked to project maintainers in the UI.
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Analysis
by VulDB Data Team • 09/23/2023
The vulnerability described in CVE-2019-6797 represents a critical information disclosure flaw within GitLab Enterprise Edition that affected multiple version ranges prior to specific security patches. This issue specifically targeted the CI/CD functionality of GitLab, where external repository integration was enabled through GitHub tokens. The flaw allowed unauthorized access to sensitive authentication credentials through the user interface, creating a significant security risk for organizations relying on GitLab's continuous integration and deployment pipelines.
The technical implementation of this vulnerability stemmed from improper access controls and output sanitization within GitLab's web interface. When users with maintainer privileges accessed project settings or CI/CD configuration pages, the system inadvertently exposed GitHub token information that should have remained restricted to administrators or specific authorized personnel. This leakage occurred during the rendering of project information in the user interface, where sensitive credential data was displayed alongside other project configuration details. The vulnerability falls under CWE-200, which specifically addresses information disclosure vulnerabilities, and represents a classic case of insufficient output filtering that violates fundamental security principles.
The operational impact of this vulnerability extends beyond simple credential exposure, as it fundamentally undermines the trust model of GitLab's access control system. Project maintainers who should only have read or limited write permissions gained access to authentication tokens that could potentially be used to access external GitHub repositories, clone private code, or modify repository settings. This exposure could enable attackers to escalate privileges within the CI/CD pipeline, potentially leading to full compromise of external repositories and associated infrastructure. The vulnerability aligns with ATT&CK technique T1552.001, which covers credentials in files, as the GitHub tokens were stored in a manner that made them accessible through the web interface.
Organizations affected by this vulnerability should immediately implement mitigation strategies including immediate patching of all GitLab instances to versions 11.5.8, 11.6.6, or 11.7.1, depending on their current version. Additionally, administrators should revoke all existing GitHub tokens used in CI/CD pipelines and regenerate new credentials with appropriate scopes. The implementation of role-based access controls should be reviewed to ensure that maintainers cannot access sensitive configuration information, and organizations should consider implementing additional monitoring for credential exposure in web interface logs. The vulnerability demonstrates the critical importance of proper input and output validation in web applications, particularly when handling sensitive authentication data, and serves as a reminder of the potential consequences when access control mechanisms fail to properly sanitize displayed information.