Go · github.com/rancher/rancher
Rancher vulnerable to command injection through unsanitized YAML parameter
A critical command injection vulnerability has been identified in the Rancher Manager cluster import endpoint /v3/import/{token}_{clusterId}.yaml through unsanitized YAML parameters. This endpoint accepts an authImage query parameter that is rendered without sanitization into a generated Kubernetes manifest template. By including URL-encoded newlines in the parameter value, an attacker can break out of the image: field to inject arbitrary YAML keys and malicious configurations, such as commands to execute malicious containers.
Exploitation of this vulnerability requires the following conditions to be met:
kubectl apply against a maliciously crafted URL.When a victim applies this compromised manifest using kubectl apply, a DaemonSet is deployed with the injected configuration. This DaemonSet:
hostNetwork: true enabled.cattle service account, which possesses cluster-admin privileges./etc/kubernetes directly from the host.command: field.An attacker who successfully exploits this vulnerability could:
Note: If you believe that you might have been impacted by this vulnerability, it's highly advised to review your clusters' logs and deployment logs for signs of malicious deployments and to rotate all service accounts and credentials that might have been exposed in such a scenario.
Please refer to the associated MITRE ATT&CK - Technique - Deploy Container for further information about this category of attack.
This vulnerability is addressed by validating the authImage parameter to ensure it contains only valid OCI image reference characters, rejecting any input containing newlines, whitespace, or other characters that could break YAML syntax.
Patched versions of Rancher include release v2.14.2, v2.13.6, v2.12.10, v2.11.14 and v2.10.12.
If upgrading to a patched version immediately is not feasible, users are encouraged to apply the following workaround:
kube-api-auth DaemonSet: Inspect downstream clusters for the kube-api-auth DaemonSet within the cattle-system namespace (which targets control-plane nodes). Review this resource configuration carefully for:command: or args: fields in the container specification.kubectl apply on any import manifests, verify that the source URLs originate from trusted sources and match expected patterns.This security issue was reported by the following collaborators according to our responsible disclosure policy:
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