Ensure that all Namespaces have Network Policies defined

How it is checked

Audit method: Shell command

ns=$(kubectl get namespaces -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}') || exit 1
np=$(kubectl get networkpolicies -A -o go-template='{{range .items}}{{.metadata.namespace}}{{"\n"}}{{end}}') || exit 1
bad=$(printf '%s\n' "$ns" | awk -v ex='^(kube-system|kube-public|kube-node-lease|gatekeeper-system|azure-arc)$' 'NF && $1 !~ ex' | grep -vxF "$(printf '%s\n' "$np" | sort -u)")
if [ -z "$bad" ]; then echo compliant; else printf '%s\n' "$bad" | sed 's/^/no NetworkPolicy: /' | head -n 25; fi

Expected output

compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Ensure the AKS cluster is using a supported network policy engine with Azure CNI Overlay, then defining explicit NetworkPolicy objects for every workload-hosting namespace. In AKS, pod traffic is unrestricted by default until policies are applied, Azure CNI Overlay supports Azure network policies, Calico, and Cilium, and Microsoft currently recommends Cilium for new policy deployments because of its scalability, security, and eBPF-based enforcement. 1. Enable or migrate to a supported network policy engine for the cluster if networkPolicy is unset or still using a legacy design. 2. Create a baseline deny-all policy in each workload namespace so traffic is blocked until explicitly allowed. 3. Add targeted ingress and egress allow rules for required application, platform, DNS, logging, and external service flows. 4.

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

tmaegis scan --target aks --level 2