28 Nov 2024 · 9 min read

Zero-Trust Kubernetes: Hardening Cloud-Native Infrastructure

A practical guide to implementing zero-trust principles in Kubernetes clusters, from network policies to runtime threat detection.

KubernetesCloud SecurityDevSecOps

As offensive tooling becomes increasingly autonomous, the line between detection and prevention keeps moving. My current focus is building systems that learn the intent behind an attack rather than the signature.

Why Default K8s Is Not Secure

Out-of-the-box Kubernetes assumes intra-cluster trust. Any compromised pod can pivot laterally unless you enforce explicit boundaries.

Layered Defence Strategy

1. Network Segmentation

Calico network policies deny all by default. Each microservice explicitly declares allowed ingress/egress.

2. RBAC Minimalism

Service accounts follow least-privilege. No cluster-admin unless absolutely necessary. Automated audits flag over-permissioned roles.

3. Runtime Protection

Falco monitors syscalls for suspicious behaviour:

  • Unexpected shell spawns
  • Privilege escalation attempts
  • Cryptomining signatures

4. Image Supply Chain

Only signed images from trusted registries. Trivy scans catch CVEs before deployment. Admission controllers reject unsigned manifests.

Telemetry Pipeline

All security events flow into a centralized ELK stack. Custom dashboards track:

  • Policy violations per namespace
  • Anomalous outbound connections
  • Secret access patterns

Outcome

After implementing these controls across production clusters, mean time to detect dropped from 4 hours to 8 minutes, and lateral movement attempts fell by 94%.

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