Do not admit containers wishing to share host IPC namespace

Error: Containers wishing to share host IPC namespace admitted

Bridgecrew Policy ID: BC_K8S_3
Checkov Check ID: CKV_K8S_3
Severity: MEDIUM

Containers wishing to share host IPC namespace admitted

Description

The host IPC namespace controls whether a pod's containers can be shared. You can administer cluster-level restrictions to ensure that containers remain isolated using PodSecurityPolicy and ensuring hostIPC is set to False.

Preventing sharing of host PID/IPC namespace, networking, and ports ensures proper isolation between Docker containers and the underlying host.

Fix - Buildtime

Kubernetes

  • Resource: PodSecurityPolicy
  • Argument: hostIPC
    Determines if the policy allows the use of HostIPC in the pod spec.
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
  name: <policy name>
spec:
+ hostIPC: false

To use a PodSecurityPolicy resource, the requesting user or target pod’s service account must be authorized to use the policy. The preferred method is to grant access to the service account. In the following example we use RBAC, a standard Kubernetes authorization mode.

A Role or ClusterRole must grant access to use the desired policies.

Kind: ClusterRole

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: <role name>
rules:
- apiGroups: ['policy']
  resources: ['podsecuritypolicies']
  verbs:     ['use']
  resourceNames:
  - <policy name>

The ClusterRole is then bound to the authorized service(s):

Kind: ClusterRoleBinding

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: <binding name>
roleRef:
  kind: ClusterRole
  name: <role name>
  apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
  name: <authorized service account name>
  namespace: <authorized pod namespace>

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