Continuous Image Security

Continuous Image Security

Image security requires continuous attention beyond initial scanning. New vulnerabilities affect previously secure images. Runtime scanning identifies vulnerabilities in deployed containers. Admission controllers prevent deployment of non-compliant images. Policy engines enforce organizational security standards automatically.

Lifecycle management ensures images receive timely updates. Image age policies force regular rebuilds incorporating security updates. Deprecated image detection identifies obsolete versions requiring replacement. Automated rebuilds triggered by base image updates maintain security currency. Organizations need processes balancing update frequency against operational stability.

Security policy as code enables consistent enforcement across environments. Open Policy Agent (OPA) and similar tools evaluate images against security policies. Policies can check for root users, exposed ports, vulnerable packages, and compliance requirements. Version-controlled policies ensure auditability and enable gradual policy evolution. Policy violations should trigger clear remediation guidance.

Securing Docker images requires attention throughout the image lifecycle from Dockerfile creation through runtime deployment. Careful base image selection, minimal attack surfaces, comprehensive scanning, and proper secrets management create strong security foundations. The next chapter explores securing container registries where these images are stored and distributed.## Container Registry Security and Image Distribution

Container registries serve as central repositories for storing and distributing Docker images across organizations. A compromised registry can distribute malicious images to entire infrastructures, making registry security critical for container supply chain protection. This chapter examines comprehensive security strategies for both public and private registries, covering access controls, vulnerability scanning, image signing, and secure distribution practices. We'll explore practical implementations using popular registry solutions while addressing common security challenges.