Disallow Host Ports

Description

Access to host ports allows potential snooping of network traffic and should not be allowed, or at minimum restricted to a known list. This control recommends the hostPort field is unset or set to 0.

Restricted Fields

• spec.containers[*].ports[*].hostPort
• spec.initContainers[*].ports[*].hostPort
• spec.ephemeralContainers[*].ports[*].hostPort

Allowed Values

• Undefined/nil
• Known list
• 0

Kyverno Policy

Refer to the Nirmata curated policies - disallow-host-ports.yaml

References

Configuration Settings

Use of host ports is disallowed. In order to be conformant with this security controle, for the resources that include the fields spec.containers[*].ports[*].hostPort, spec.initContainers[*].ports[*].hostPort, and spec.ephemeralContainers[*].ports[*].hostPort must either be unset or set to 0.

=(ephemeralContainers):
  - =(ports):
    - =(hostPort): 0
=(initContainers):
  - =(ports):
    - =(hostPort): 0
containers:
  - =(ports):
    - =(hostPort): 0

Resource Example

Below is a Deployment resource example where hostPort field is not set at all. If present, it should be set to 0.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: gooddeployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: app
  template:
    metadata:
      labels:
        app: app
    spec:
      initContainers:
      - name: initcontainer01
        image: dummyimagename
      - name: initcontainer02
        image: dummyimagename
        ports:
        - name: web-insecure
          containerPort: 8080
      containers:
      - name: container01
        image: dummyimagename
        ports:
        - name: web-insecure
          containerPort: 8080