Supply Chain Security Overview
What is Supply Chain Security in Kubernetes?
Supply Chain Security in Kubernetes ensures the integrity, authenticity, and security of software components across the entire development lifecycle—from source code to deployment.
Why is Supply Chain Security Important for CKS?
- Prevents supply chain attacks like dependency poisoning and build system compromises.
- Ensures image integrity and prevents unauthorized modifications.
- Verifies that only trusted artifacts are deployed to production.
- Helps comply with security standards like SLSA, NIST SSDF, and CIS Benchmarks.
Key Components of Kubernetes Supply Chain Security
1. Source Code Security
- Use code signing (e.g., Sigstore, GPG) to verify commit integrity.
- Implement code scanning tools (e.g., Snyk, Trivy, Checkov) to detect vulnerabilities.
- Enforce branch protection and code reviews in Git repositories.
- Enable developer access control with IAM and MFA.
Example: Scan for vulnerabilities using Trivy
sh
trivy fs .
2. Build Security
- Use isolated and hardened CI/CD environments (e.g., GitHub Actions, GitLab CI/CD, Tekton).
- Sign and verify builds using Sigstore Cosign.
- Detect and block malicious dependencies with Dependency Track or Snyk.
Example: Signing a container image with Cosign
sh
cosign sign --key cosign.key my-registry.io/my-image:latest
Example: Verifying an image signature
sh
cosign verify my-registry.io/my-image:latest --key cosign.pub
3. Artifact Security
- Store and distribute images securely via private container registries (e.g., Amazon ECR, Google Artifact Registry).
- Use immutable tags and avoid using
latest. - Scan images for vulnerabilities before deployment using Trivy or Clair.
Example: Scan an image for vulnerabilities
sh
trivy image my-registry.io/my-image:latest
4. Deployment Security
- Enforce Admission Controllers (e.g., OPA Gatekeeper, Kyverno) to block untrusted images.
- Use Pod Security Standards (PSS) to prevent privilege escalation.
- Require only signed images for deployments with Sigstore or Notary.
Example: Kyverno policy to allow only signed images
yaml
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
name: verify-image-signatures
spec:
validationFailureAction: Enforce
rules:
- name: check-signature
match:
resources:
kinds:
- Pod
verifyImages:
- image: "my-registry.io/*"
key: cosign.pub
5. Runtime Security
- Use Runtime Security tools (e.g., Falco, Tracee) to detect anomalous behavior.
- Enforce Least Privilege Access (e.g., dropping unnecessary capabilities in Pods).
- Monitor and log Kubernetes API activity using Audit Logs and SIEM solutions.
Example: Monitor unexpected network activity using Falco
sh
falco --list
Best Practices for Supply Chain Security
✅ Secure the source code with version control best practices and scanning tools. ✅ Harden CI/CD pipelines to prevent tampering. ✅ Sign and verify artifacts before deployment. ✅ Enforce admission controls to block untrusted containers. ✅ Monitor runtime security using tools like Falco and Audit Logs.
Reference: Supply Chain Security Best Practices