Security Primer

Kubernetes security isn't just one feature — it's a collection of layered controls designed to protect clusters, workloads, data, and users. Understanding how these layers work together is critical to hardening your environment.

The 4Cs of Kubernetes Security

Kubernetes security builds on the 4Cs model:

  1. Cloud / Infrastructure
  2. Cluster
  3. Container
  4. Code

Each layer provides opportunities for both defense and attack. Strong security means securing each level, not just one.

Common Threat Vectors

Surface Area Risk Example
Misconfigured RBAC Users can access or delete sensitive resources
Insecure Pods Privileged containers, exposed hostPath
Unsafe Images Vulnerable base images or untrusted sources
Over-permissive Network No NetworkPolicy = open lateral movement
Secrets in plain text Poorly handled sensitive data

Key Kubernetes Security Concepts

Here’s a quick overview of what you’ll encounter in the upcoming sections:

🔐 Authentication & Authorization

  • Authentication – Who are you?
  • Authorization (RBAC) – What can you do?
  • Admission Controllers – Should this action be allowed or mutated?

These mechanisms protect access to the Kubernetes API and workloads.

🧱 Pod Security

  • Prevent privilege escalation
  • Block host access
  • Apply security contexts
  • Enforce using Pod Security Admission (PSA)

🕵️‍♂️ Audit Logs

  • Record every API request
  • Help detect suspicious or unauthorized behavior
  • Required for compliance in regulated environments

🔍 Image Scanning

  • Analyze container images for known vulnerabilities
  • Prevent deployment of unsafe workloads
  • Tools: Trivy, Grype, Cosign, Clair

🔐 Secrets Management

  • Use Secret objects (with encryption at rest)
  • Avoid embedding secrets in images or environment variables
  • Consider sealed secrets or external tools like Vault

🔒 Network Security

  • Use NetworkPolicies to restrict Pod-to-Pod traffic
  • Combine with Ingress controllers and TLS
  • Isolate workloads by namespace or label

Shift Left: DevSecOps in Kubernetes

Modern Kubernetes security integrates with CI/CD pipelines:

  • Scan containers during build
  • Validate policies (e.g., with OPA/Gatekeeper)
  • Reject non-compliant resources before deployment

Summary

Kubernetes security is broad and layered. The upcoming sections break it down into actionable areas like:

  • Pod-level hardening (PSA)
  • Audit and observability
  • Image security and scanning
  • Runtime policies and network controls

Security isn't a checkbox — it's a process. Let’s dig into each piece.