CVE-2022-3740 in Community Edition
Summary
by MITRE • 01/26/2023
An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.9 prior to 15.3.5, 15.4 prior to 15.4.4, and 15.5 prior to 15.5.2. A group owner may be able to bypass External Authorization check, if it is enabled, to access git repositories and package registries by using Deploy tokens or Deploy keys .
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Analysis
by VulDB Data Team • 02/19/2023
This vulnerability in GitLab CE/EE represents a critical authorization bypass flaw that undermines the security controls designed to restrict access to repository resources. The issue affects versions from 12.9 through 15.5.1, creating a persistent security gap that allows unauthorized access to sensitive code repositories and package registries. The vulnerability specifically targets the external authorization mechanisms that are typically enforced to control access based on user roles and permissions. When external authorization is enabled, the system should enforce strict access controls that prevent unauthorized users from accessing resources they should not be able to reach. However, this flaw enables group owners to circumvent these controls through the use of deploy tokens or deploy keys, which are legitimate authentication mechanisms designed for automated access to repositories. This represents a fundamental breakdown in the principle of least privilege that should govern access to source code and package management systems.
The technical nature of this vulnerability stems from improper validation of access permissions when deploy tokens or deploy keys are used within the context of group ownership. Group owners normally have elevated privileges within their respective groups, but these privileges should not extend to bypassing external authorization checks that are designed to enforce more granular access controls. The flaw occurs during the authentication and authorization process where the system fails to properly verify that the access request aligns with the external authorization policies. This creates a situation where legitimate deploy tokens and keys can be used to gain access to resources that should be restricted to specific user roles or external authorization policies. The vulnerability is particularly concerning because deploy tokens and keys are commonly used for automated deployment processes, continuous integration systems, and other legitimate operational tasks, making this bypass potentially exploitable in production environments.
The operational impact of this vulnerability extends beyond simple unauthorized access to include potential data exposure, code integrity compromise, and unauthorized package distribution. Attackers who exploit this vulnerability can access sensitive source code repositories, potentially obtaining confidential information, intellectual property, or security-sensitive code. Additionally, access to package registries could enable attackers to tamper with software packages, inject malicious code, or disrupt software distribution processes. The ability to bypass external authorization checks means that attackers can potentially access resources that should be restricted to specific external identity providers or authorization systems. This vulnerability affects the core security model of GitLab installations that rely on external authorization to control access to repositories and packages, potentially compromising the security posture of organizations that depend on these systems for code management and software distribution.
Organizations should immediately implement mitigations that include upgrading to the patched versions of GitLab where available, which are 15.3.5, 15.4.4, and 15.5.2 respectively. The upgrade process should be prioritized as these versions contain the necessary fixes to address the authorization bypass mechanism. Administrators should also review existing deploy tokens and keys to ensure they are properly configured with appropriate access controls and that unnecessary permissions have been revoked. Implementing additional monitoring and logging controls around access to repositories and package registries can help detect potential exploitation attempts. The vulnerability aligns with CWE-284 which addresses improper access control, and may be related to ATT&CK techniques involving privilege escalation and credential access. Organizations should also consider implementing network-level controls and access restrictions to limit exposure while patches are being deployed, particularly for environments where immediate upgrades are not feasible. Regular security assessments of authorization mechanisms should be conducted to identify similar issues in other systems and processes that may be vulnerable to similar authorization bypass techniques.