Profile applicability: Level 1
Use network policies to isolate traffic in your cluster network.
Running different applications on the same Kubernetes cluster creates a risk of one
compromised application attacking a neighboring application. Network segmentation
is important to ensure that containers can communicate only with those they are supposed
to. A network policy is a specification of how selections of pods are allowed to communicate
with each other and other network endpoints.
Once there is any Network Policy in a namespace selecting a particular pod, that pod
will reject any connections that are not allowed by any Network Policy. Other pods
in the namespace that are not selected by any Network Policy will continue to accept
all traffic.
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NoteBy default, network policies are not created.
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Impact
Once there is any Network Policy in a namespace selecting a particular pod, that pod
will reject any connections that are not allowed by any Network Policy. Other pods
in the namespace that are not selected by any Network Policy will continue to accept
all traffic.
Audit
Run the below command and review the
NetworkPolicy objects created in the cluster.kubectl get networkpolicy --all-namespaces
Ensure that each namespace defined in the cluster has at least one Network Policy.
Remediation
Follow the documentation and create
NetworkPolicy objects as you need them.