Securing the Container Orchestrator
Kubernetes defaults are designed for developer convenience, not security. A zero-trust posture assumes that every container is a potential entry point for attackers and locks down communication paths.
Enforcing Strict Network Policies
By default, Kubernetes pods can communicate with any other pod in the cluster.
• Deny-All Default Policy: Start with a global default-deny policy for all ingress and egress traffic, then whitelist explicit connections.
• Mutual TLS (mTLS): Implement a service mesh (like Istio or Linkerd) to encrypt all service-to-service communications and enforce cryptographic identities.
Hardening Container Execution
1. ReadOnly Root Filesystem: Configure container security contexts to prevent write access to the host node.
2. Non-Root Users: Enforce policies that prevent container execution as the root user.
3. Admission Controllers: Use gatekeeper policies to block unverified images or privileged containers from deploying to production namespaces.