apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-host-namespaces
  annotations:
    policies.kyverno.io/title: Disallow Host Namespaces
    policies.kyverno.io/category: DoD STIG
    policies.kyverno.io/severity: high
    policies.kyverno.io/description: >-
      STIG V-242386: Containers must not share the host process ID, IPC,
      or network namespace. Sharing host namespaces allows containers to
      access host-level resources and break isolation boundaries.
spec:
  validationFailureAction: Enforce
  background: true
  rules:
    - name: host-namespaces
      skipBackgroundRequests: true
      match:
        any:
          - resources:
              kinds:
                - Pod
      exclude:
        any:
          - resources:
              namespaces:
                - kube-system
                - rook-ceph
                - istio-system
                - prometheus
                - kyverno
                - crowdsec
      validate:
        allowExistingViolations: true
        message: >-
          Sharing host PID, IPC, or network namespaces is not allowed (STIG V-242386).
        pattern:
          spec:
            =(hostPID): false
            =(hostIPC): false
            =(hostNetwork): false