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9.3 Security Container Images

Securing container images is crucial to ensure that the software you run in your containers is free from vulnerabilities and has not been tampered with. Here are some best practices to help you secure your container images:

1. Use Trusted Base Images:

  • Start with trusted base images from reputable sources, such as official repositories or well-known organizations.
  • Trusted base images are typically maintained, regularly patched, and scanned for vulnerabilities, reducing the risk of starting with an insecure foundation.

2. Scan Images for Vulnerabilities:

  • Utilize vulnerability scanning tools to scan your container images for known vulnerabilities.
  • These tools analyze the image's software components and check for any security vulnerabilities, providing you with a report to address potential risks.

3. Enable Image Signing and Verification:

  • Implement image signing and verification mechanisms to ensure the integrity and authenticity of your container images.
  • Signing images using digital signatures allows you to verify their origin and detect any unauthorized modifications.

4. Regularly Update Images:

  • Keep your container images up to date by regularly pulling the latest versions from trusted sources.
  • Updates often include security patches, bug fixes, and improvements, reducing the chances of running containers with known vulnerabilities.

5. Use Minimal Image Layers:

  • Opt for minimal image layers by following best practices for building efficient Docker images.
  • Minimizing the number of layers reduces the attack surface and makes it easier to track and manage vulnerabilities within the image.

6. Practice Image Immutability:

  • Treat container images as immutable artifacts that should not be modified or tampered with once built.
  • By enforcing immutability, you can ensure that your images remain consistent, reducing the risk of unauthorized modifications.

7. Store Images in Secure Registries:

  • Store your container images in secure image registries that provide access control, authentication, and encryption features.
  • Choose reputable and trusted registries that prioritize security to safeguard your images from unauthorized access or tampering.

8. Implement Least Privilege Principles:

  • Follow the principle of least privilege when defining container image permissions.
  • Only include the necessary software components and libraries in your images, removing any unnecessary tools or dependencies that could introduce security risks.

9. Regularly Patch and Update Images:

  • Stay vigilant and apply patches and updates to your container images as new security vulnerabilities are discovered.
  • Regularly monitor security advisories and patches for the software components within your images, and promptly update them to address known vulnerabilities.


By following these best practices, you can significantly enhance the security of your container images and reduce the risk of running containers with vulnerabilities.