Vulnerability Discussion

Separating user functionality from management functionality is a requirement for all the components within the Kubernetes Control Plane. Without the separation, users may have access to management functions that can degrade the Kubernetes architecture and the services being offered, and can offer a method to bypass testing and validation of functions before introduced into a production environment.

Satisfies: SRG-APP-000243-CTR-000600, SRG-APP-000431-CTR-001065, SRG-APP-000211-CTR-000530, SRG-APP-000243-CTR-000595

Check

System namespaces are reserved and isolated.

To view the available namespaces, run the command:
kubectl get namespaces

The namespaces to be validated include:
default
kube-public
kube-system
kube-node-lease

For the default namespace, execute the commands:
kubectl config set-context --current --namespace=default
kubectl get all

For the kube-public namespace, execute the commands:
kubectl config set-context --current --namespace=kube-public
kubectl get all

For the kube-node-lease namespace, execute the commands:
kubectl config set-context --current --namespace=kube-node-lease
kubectl get all

The only return values are the Kubernetes service objects (e.g., service/kubernetes).

For the kube-system namespace, execute the commands:
kubectl config set-context --current --namespace=kube-system
kubectl get all

The values returned include the following resources:
- ETCD
- Helm
- Kubernetes API Server
- Kubernetes Controller Manager
- Kubernetes Proxy
- Kubernetes Scheduler
- Kubernetes Networking Components
- Ingress Controller Components
- Metrics Server

If a return value from the "kubectl get all" command is not the Kubernetes service, one from the above lists, or a service otherwise approved by your Information Systems Security Officer (ISSO), this is a finding.

Fix

System namespaces are reserved and isolated.

A resource cannot move to a new namespace; the resource must be deleted and recreated in the new namespace.

kubectl delete <resource_type> <resource_name>
kubectl create -f <resource.yaml> --namespace=<user_created_namespace>