The kubewarden-controller AdmissionPolicy and AdmissionPolicyGroup policies can be used to alter PolicyReport resources

Vulnerability Description

kubewarden-controller is a Kubernetes controller that allows you to dynamically register Kubewarden admission policies. By design, AdmissionPolicy and AdmissionPolicyGroup can evaluate only namespaced resources. The resources to be evaluated are determined by the rules provided by the user when defining the policy. There might be Kubernetes namespaced resources that should not be validated by AdmissionPolicy and by the AdmissionPolicyGroup policies because of their sensitive nature. For example, PolicyReport are namespaced resources that contain the list of non compliant objects found inside of a namespace. An attacker can use either an AdmissionPolicy or an AdmissionPolicyGroup to prevent the creation and update of PolicyReport objects to hide non-compliant resources. Moreover, the same attacker might use a mutating AdmissionPolicy to alter the contents of the PolicyReport created inside of the namespace. Starting from the 1.21.0 release, the validation rules applied to AdmissionPolicy and AdmissionPolicyGroup have been tightened to prevent them from validating sensitive types of namespaced resources.

References

• https://github.com/kubewarden/kubewarden-controller/security/advisories/GHSA-fc89-jghx-8pvg
• https://github.com/kubewarden/kubewarden-controller/commit/8124039b5f0c955d0ee8c8ca12d4415282f02d2c