Container Scanning

Bake image scanning into CI/CD pipelines
Adopt inline scanning to prevent leaks of secrets
  • Implement inline image scanning, scanning images directly from the CI/CD pipeline without needing a staging repository
  • With inline image scanning, only the scan metadata is sent to the scanning tool (preventing a leak if the image contained secrets by mistake)
Perform image scanning at registries
  • Include image scanning as one of the first steps after pushing to a registry
  • It ensures images have been scanned before running
Leverage Kubernetes admission controllers
  • Leverage Kubernetes to check the images before scheduling them, blocking unscanned or vulnerable images from being deployed onto the cluster
  • Scanning tools usually offer a validating webhook that can trigger an image scanning on demand and then return a validation decision
  • An admission controller can call this webhook before scheduling an image
Pin image versions
  • Sometimes, the image you scan is not the same one you deploy in your Kubernetes cluster
  • This can happen when you use mutable tags, like latest or staging
Scan for OS vulnerabilities
  • Even if you didn’t introduce a new vulnerability in your image, it will be susceptible to those in the base image
  • That's why your scanning tool should actively track vulnerability feeds for known vulnerable images and notify you if you're using one of those
Flag vulnerabilities quickly across Kubernetes deployments
  • What happens with images that are already running? (i.e., imagine that you scan and deploy an image, and right after doing so a new vulnerability is found in it)
  • Continuously scanning the images that are running in the cluster
Reduce attack surface
  • Make use of distroless images
  • Scan for vulnerabilities in third-party libraries
  • Optimize layer ordering
  • Scan for misconfigurations in Dockerfiles
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