← Policy catalog
</> ValidatingAdmissionPolicy · Apache-2.0

Shares the Host Network Namespace

pod-hostnetwork

severityHigh resourcePods productKubernetes bundles2

Host networking removes network namespace isolation, letting the workload sniff all node traffic, bind directly to node ports and reach loopback-bound node services such as the kubelet and local metadata proxies.

Rejects unless

!has(object.spec.hostNetwork) || object.spec.hostNetwork == false

Using hostNetwork is disallowed. spec.hostNetwork must be undefined or set to false.

Remediation

Remove spec.hostNetwork or set it to false and expose the workload through a Service instead. Field: spec.hostNetwork.

Applies to

  • pods · v1 · CREATE, UPDATE

Manifest

apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicy
metadata:
  name: pod-hostnetwork
  annotations:
    kubeapt.io/uuid: "0905d194-7177-43ee-a9cd-49a5d3e10e79"
    security.kubeapt.io/displayName: "Shares the Host Network Namespace"
    security.kubeapt.io/description: "Host networking removes network namespace isolation, letting the workload sniff all node traffic, bind directly to node ports and reach loopback-bound node services such as the kubelet and local metadata proxies."
    security.kubeapt.io/resource: "Pods"
    security.kubeapt.io/severity: "High"
    security.kubeapt.io/remediation: "Remove spec.hostNetwork or set it to false and expose the workload through a Service instead. Field: spec.hostNetwork."
    security.kubeapt.io/product: "Kubernetes"
spec:
  failurePolicy: Fail
  matchConstraints:
    resourceRules:
    - apiGroups:
      - ''
      apiVersions:
      - v1
      operations:
      - CREATE
      - UPDATE
      resources:
      - pods
  validations:
  - expression: |
      !has(object.spec.hostNetwork) || object.spec.hostNetwork == false
    message: |
      Using hostNetwork is disallowed. spec.hostNetwork must be undefined or set to false.

Save it as pod-hostnetwork.yaml — the commands below assume that name.

Validate with kubeapt

Check a workload against this one policy, before anything is installed on a cluster.

$ kubeapt validate -p ./pod-hostnetwork.yaml -r ./workload.yaml

Or without the file, from the published policy set — -r takes a directory too:

$ kubeapt policies download && kubeapt validate --policy-name pod-hostnetwork -r ./manifests

Or against every namespace in the cluster your kubeconfig points at:

$ kubeapt validate --policy-name pod-hostnetwork -A

Bundles

Source

View policy.yaml on GitHub →