In all Kubernetes versions prior to v1.10.11, v1.11.5, and v1.12.3, incorrect handling of error responses to proxied upgrade requests in the kube-apiserver allowed specially crafted requests to establish a connection through the Kubernetes API server to backend servers, then send arbitrary requests over the same connection directly to the backend, authenticated with the Kubernetes API server's TLS credentials used to establish the backend connection.
There are 2 POC been released for CVE-2018-1002105.
Authenticated PoC
Proof-of-Concept exploit for CVE-2018-1002105. The current exploit requires create and get privileges on pods and pods/exec. Support has been added for portforward and attach, which require similar permissions.
The current PoC dumps the secrets from the default etcd-kubernetes pod.
Unauthenticated PoC
The unauthenticated PoC allows privilege escalation within the context of the exposed API. Depending on the functionalities of the API it might be possible to get code execution on pods. This demo currently exploits the bug to gain cluster-admin rights on the servicecatalog.k8s.io API. This exploit should also work for metrics.k8s.io or any API exposed through the aggregated layer.
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