k8s-hardening-audit

Kubernetes Hardening Audit

Overview

Use this skill to assess MCP Runtime's cluster posture: RBAC graph, Pod Security Standards, NetworkPolicy enforcement, manifest hygiene, and CIS benchmark compliance. Findings use the shared template at ../_shared/FINDINGS-TEMPLATE.md.

For runtime authn/authz, gateway policy, and protocol fuzzing, use security-audit-platform. For images and supply chain, use supply-chain-audit.

Step 1 — Inventory

Repo-owned namespaces (per CLAUDE.md):

• mcp-runtime — operator.
• mcp-sentinel — api, ui, ingest, processor, gateway, observability.
• mcp-servers — user MCP server workloads, gateway sidecars.
• registry — Distribution v2 registry.
• traefik — ingress controller (or kube-system/traefik on k3s).

For each:

NS=mcp-sentinel
kubectl -n "$NS" get all,sa,role,rolebinding,networkpolicy -o name
kubectl get clusterrole,clusterrolebinding -o name | grep -iE 'mcp|sentinel'

Record SA → Role/ClusterRole bindings as a graph; this becomes the input to RBAC analysis.

Step 2 — RBAC graph analysis

Install the helpers:

go install github.com/corneliusweig/rakkess/cmd/rakkess@latest
go install github.com/reactiveops/rbac-lookup@latest

Per ServiceAccount:

for sa in $(kubectl -n mcp-sentinel get sa -o name); do
  echo "=== $sa ==="
  rakkess --sa "$(echo $sa | cut -d/ -f2)" --namespace mcp-sentinel
done

Findings to flag:

• * verbs on secrets → High unless explicitly justified by a single controller and scoped to a single namespace.
• Cluster-scoped roles on workload SAs → High; scope to a Role unless the controller genuinely watches cluster-wide.
• pods/exec, pods/portforward, pods/attach → High outside break-glass paths.
• serviceaccounts/token create → High; token impersonation primitive.
• escalate or bind on roles → Critical.
• Bindings to system:authenticated or system:unauthenticated → Critical.

Confirm Traefik narrowing (CLAUDE.md): bundled manifests should watch only registry, mcp-sentinel, mcp-servers. Any extra namespace with a traefik-watch Role binding without a documented reason is a Medium finding.