Certified Kubernetes Security Specialist (CKS)

The CKS certification tests your ability to secure Kubernetes clusters and workloads. It’s hands-on, intense, and assumes you already understand Kubernetes deeply (CKA is a prerequisite).

🧠 Exam Overview

  • Format: Hands-on lab with scenarios
  • Duration: 2 hours
  • Passing score: 67%
  • Prerequisite: Active CKA certification
  • Open book: Access to kubernetes.io + GitHub repos

📋 Domains & Weights

Domain Weight
Cluster Setup 10%
System Hardening 15%
Minimize Microservice Vulnerabilities 20%
Supply Chain Security 20%
Monitoring, Logging & Runtime Security 25%
RBAC & Network Policies 10%

✅ What You Should Master

1. Cluster Setup (10%)

  • TLS certificates & CA bundles
  • Encrypt secrets at rest (KMS + EncryptionConfiguration)
  • Audit policy config and log location
  • API server flags: --audit-log-path, --enable-admission-plugins

2. System Hardening (15%)

  • Restrict host access: block hostPath, hostNetwork, privileged
  • Use securityContext:
  • runAsNonRoot, readOnlyRootFilesystem, allowPrivilegeEscalation: false
  • Restrict capabilities (capabilities.drop: ["ALL"])
  • Pod Security Admission (PSA) with restricted profile
  • Runtime namespace protections (AppArmor / seccomp)

3. Minimize Microservice Vulnerabilities (20%)

  • Scan images with Trivy, Grype, or Dockle
  • Sign images with cosign and verify before deployment
  • Use scratch/minimal base images
  • Avoid running as root in Dockerfiles
  • Validate liveness/readiness probe security

4. Supply Chain Security (20%)

  • Use trusted registries and signed images
  • Scan YAML manifests for insecure configurations (e.g., kubesec, kube-score)
  • Admission control:
  • Validating/mutating webhooks
  • Gatekeeper/OPA policies
  • ImagePullPolicy: Always

5. Monitoring, Logging & Runtime Security (25%)

  • Audit policy and log filtering
  • Tools:
  • Falco (real-time threat detection)
  • Sysdig, AuditD, or ausearch
  • Monitor execs, privilege escalation, network anomalies
  • Understand and tune Falco rules

6. RBAC & Network Policies (10%)

  • Create Role, ClusterRole, RoleBinding, ClusterRoleBinding
  • Apply NetworkPolicy to restrict Pod traffic (ingress/egress)
  • Avoid * verbs and * resources in RBAC
  • Restrict access by namespace and API group

⚙️ Practice Tips

  • Practice scanning + signing images:
  • trivy image nginx:latest
  • cosign sign --key cosign.key myrepo/app:1.0
  • Create test policies for:
  • PSA
  • RBAC + kubectl auth can-i
  • NetworkPolicy deny-by-default rules
  • Trigger and detect audit events
  • Write Falco rules for suspicious behaviors

🧪 Test Environment Tips

Summary

CKS is all about applying security best practices under pressure. You’ll configure audit logs, write PodSecurity controls, patch RBAC, restrict networks, and scan or sign container images - all in live clusters.

Hands-on practice is key. Read YAML fast. Think like an attacker.