We recently had a security audit that highlighted risks in our Kubernetes networking. If one pod is compromised, what specific tools or configurations should I use to prevent an attacker from accessing our secrets or moving to other namespaces?
3 answers
You need to implement "Zero Trust" networking within the cluster. By default, K8s allows all pods to talk to each other. Use Network Policies to enforce a "Deny All" ingress/egress rule, and then explicitly allow only necessary communication. I also recommend a Service Mesh like Istio or Linkerd for mTLS encryption between services; this ensures that even if traffic is intercepted, it's unreadable. Furthermore, use RBAC to ensure pods have the least privilege—specifically, avoid using the "default" ServiceAccount and never mount the API token unless the pod absolutely needs to talk to the K8s API.
Have you looked into using a container-optimized OS like Bottlerocket or Talos to reduce the attack surface of the actual nodes themselves?
Implementing a Policy Engine like OPA (Open Policy Agent) or Kyverno can help you automatically block any pod deployments that don't meet your security standards.
Kyverno has been a lifesaver for us. It allows us to enforce things like "no root containers" without having to manually check every single YAML file.
We haven't switched OS yet, but that's a great idea. We are currently using standard Ubuntu nodes, which definitely have more packages installed than we actually need for production.