CVE-2019-6287 in Rancher
Summary
by MITRE
In Rancher 2.0.0 through 2.1.5, project members have continued access to create, update, read, and delete namespaces in a project after they have been removed from it.
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Analysis
by VulDB Data Team • 05/28/2020
The vulnerability described in CVE-2019-6287 represents a critical access control flaw within the Rancher container management platform that affects versions 2.0.0 through 2.1.5. This issue falls under the category of privilege escalation and unauthorized access, specifically targeting the namespace management capabilities within project environments. The flaw manifests when project members retain elevated permissions even after their removal from a project, creating a persistent security risk that undermines the intended access control mechanisms. This vulnerability directly impacts the principle of least privilege and role-based access control that are fundamental to container orchestration platforms, as it allows former project members to maintain administrative capabilities within previously accessed project namespaces.
The technical implementation of this vulnerability stems from inadequate session management and permission synchronization mechanisms within Rancher's authorization framework. When a user is removed from a project, the system fails to properly invalidate their existing session tokens or revoke their namespace-level permissions, resulting in a state where the removed user can continue performing create, update, read, and delete operations on project namespaces. This represents a classic case of improper privilege management where the system does not properly enforce access control decisions upon user role changes. The flaw is particularly concerning as it operates at the namespace level, which serves as a fundamental isolation boundary in Kubernetes environments, making it a potential vector for data leakage, unauthorized modifications, and privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass significant security implications for containerized environments. Former project members could potentially modify or delete critical namespace resources, access sensitive application data, or disrupt the operational integrity of the affected projects. This vulnerability creates a window of opportunity for malicious actors who might exploit the lingering permissions to conduct data exfiltration, deploy unauthorized workloads, or manipulate namespace configurations. The persistence of these permissions across project membership changes undermines the security posture of organizations relying on Rancher for container orchestration, as it allows for continued unauthorized access even after proper administrative procedures have been followed to remove users from projects.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to Rancher versions 2.1.6 or later where the issue has been addressed through proper session invalidation and permission synchronization mechanisms. The fix involves ensuring that when project membership is modified, all associated session tokens are invalidated and permissions are properly synchronized across the system. Security teams should conduct comprehensive audits of project memberships and permissions to identify any potential exploitation that may have occurred during the vulnerable period. Additionally, implementing monitoring solutions that track project membership changes and permission modifications can help detect anomalous behavior patterns that might indicate unauthorized access attempts. This vulnerability aligns with CWE-285, which addresses improper authorization issues, and could be leveraged by adversaries following ATT&CK techniques related to privilege escalation and persistence within containerized environments.