Image Scanning & Registry Security
Why This Matters:
Container images and registries are common attack vectors in cloud-native applications. Without proper scanning and registry controls, you risk deploying vulnerabilities and exposing your supply chain.
This guide covers actionable best practices for scanning your images, securing registries, enforcing automated policies, and defending against real-world threats.
Best Practices for Image & Registry Security
- Scan all container images for vulnerabilities before deployment using automated tools like Trivy, Clair, or Aqua.
- Use only trusted, private registries (Docker Hub with content trust, Azure Container Registry, Amazon ECR) and restrict image pulls to expected sources.
- Implement image signing (Notary, Cosign, Sigstore) to verify integrity and provenance.
- Enforce Admission Controllers (Kyverno, OPA Gatekeeper) to block deployments of untrusted or vulnerable images automatically.
- Update base images regularly, and rebuild workloads promptly to patch new CVEs.
- Automate registry mirror updates and regularly synchronize to prevent supply chain risks.
- Monitor registry access logs for unauthorized or suspicious downloads.
- Integrate image scanning into your CI/CD pipeline for shift-left security during build and deploy.
Common Threats
- Deploying images with known security vulnerabilities due to missing or outdated scans.
- Pulling from public registries exposes your environment to supply chain attacks.
- Using unsigned images or third-party artifacts lacking provenance and integrity.
- Registry misconfigurations leading to unauthorized access or malicious overwrites.
Recommended Tools
- Trivy, Aqua, Clair - Automated image vulnerability scanning
- Sigstore, Cosign, Notary - Image signing, integrity, and provenance
- Kyverno, OPA Gatekeeper - Policy enforcement at deploy/admission time
- Prometheus + Grafana - Monitor registry activity and scan status