Container Image Scanning Fundamentals

Container Image Scanning Fundamentals

Container image scanning begins with understanding image composition and identifying all components requiring security analysis. Modern scanners decompress container images layer by layer, cataloging operating system packages, programming language dependencies, and application files. This comprehensive inventory forms the foundation for vulnerability detection, license compliance checking, and configuration validation.

Vulnerability detection in containers requires checking multiple sources. Operating system packages are matched against distribution-specific security databases like Alpine SecDB, Debian Security Tracker, and Red Hat Security Advisories. Application dependencies undergo Software Composition Analysis using language-specific vulnerability databases. Binary analysis identifies statically linked libraries that package managers might miss. Each detection method addresses different risk vectors in the container stack.

Configuration scanning has become increasingly important as container security breaches often result from misconfigurations rather than unpatched vulnerabilities. Scanners analyze Dockerfile instructions for security anti-patterns like running as root, exposing unnecessary ports, or including secrets in image layers. Runtime configuration files undergo policy validation to ensure containers follow security best practices like dropping unnecessary capabilities and implementing proper resource limits.