CVE-2020-13264 in Community Edition
Summary
by MITRE
Kubernetes cluster token disclosure in GitLab CE/EE 10.3 and later through 13.0.1 allows other group maintainers to view Kubernetes cluster token
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Analysis
by VulDB Data Team • 10/26/2020
This vulnerability exists in GitLab Community Edition and Enterprise Edition versions 10.3 through 13.0.1 where group maintainers can access Kubernetes cluster tokens belonging to other groups. The flaw represents a critical authorization bypass that violates fundamental security principles of least privilege and separation of concerns. When users with group maintainer permissions attempt to view cluster information, the system inadvertently exposes sensitive authentication credentials that should be restricted to cluster administrators or owners only. This represents a direct violation of the principle of least privilege as defined in the CWE-250 standard for unauthorized access to privileges.
The technical implementation of this vulnerability stems from improper access control checks within GitLab's Kubernetes cluster management functionality. When group maintainers navigate to cluster configuration pages, the application fails to properly validate whether the requesting user has appropriate authorization levels to access specific cluster tokens. This allows users with lower privilege levels to escalate their access and obtain authentication credentials that could enable them to compromise the underlying Kubernetes infrastructure. The vulnerability specifically affects the cluster token disclosure mechanism and represents a classic case of insufficient authorization controls as categorized under CWE-285.
The operational impact of this vulnerability is severe and multifaceted. An attacker with group maintainer privileges could gain unauthorized access to production Kubernetes clusters, potentially leading to complete compromise of containerized applications and infrastructure. This access could enable lateral movement within the cluster, privilege escalation, data exfiltration, and service disruption. The vulnerability also creates a significant risk for organizations that rely on GitLab for DevOps operations, as it undermines the security boundaries between different teams and projects. According to ATT&CK framework tactic TA0006 (Credential Access), this vulnerability directly enables techniques such as credential dumping and privilege escalation through unauthorized access to authentication tokens.
Organizations should immediately upgrade to GitLab versions 13.1.0 or later where this vulnerability has been addressed through proper access control enforcement. The mitigation strategy involves implementing strict role-based access controls and ensuring that only cluster owners or administrators have access to sensitive cluster tokens. Additionally, organizations should conduct thorough audits of their GitLab permissions and implement network segmentation to limit access to Kubernetes clusters. Security teams should monitor for any suspicious activities related to cluster access and implement proper logging of all cluster token access attempts. The vulnerability highlights the importance of proper access control validation and demonstrates how insufficient authorization checks can lead to severe security breaches in modern DevOps environments. Organizations should also consider implementing additional security controls such as just-in-time access provisioning and multi-factor authentication for cluster administrators to further reduce the attack surface.