What is SCA (Software Composition Analysis)?

Software Composition Analysis (SCA) is the automated identification and analysis of third-party and open source components in software applications. Modern applications typically consist of 80-90% open source code through dependencies, making SCA essential for understanding what's actually running in production and whether any of those components have known security vulnerabilities.

What SCA analyzes

SCA tools examine:

1. Direct dependencies: Libraries explicitly declared in package manifests (package.json, requirements.txt, go.mod, pom.xml)
2. Transitive dependencies: Libraries pulled in by your direct dependencies, often several levels deep
3. Vendored code: Third-party code copied directly into your repository
4. Container base images: OS packages and libraries included in Docker images
5. License information: What legal obligations each component carries

Why SCA matters

Vulnerabilities in dependencies are your vulnerabilities. When a security flaw is discovered in a popular library, every application using that library becomes vulnerable. High-profile incidents like Log4Shell, Heartbleed, and the event-stream compromise demonstrated how a single dependency vulnerability can affect millions of applications.

You can't secure what you don't know about. Many teams don't have visibility into their transitive dependencies. An application with 10 direct dependencies might have 200+ transitive dependencies, any of which could introduce risk.

How SCA works

SCA tools build a Software Bill of Materials (SBOM) by parsing dependency manifests and lock files. This inventory is then compared against vulnerability databases like:

• CVE: The Common Vulnerabilities and Exposures database
• NVD: NIST's National Vulnerability Database
• GitHub Advisory Database
• OSV: The Open Source Vulnerability database

When matches are found, SCA tools report the vulnerability severity, affected versions, and available fixes.

Beyond vulnerabilities

Modern SCA also addresses:

• License compliance: Identifying licenses (MIT, GPL, Apache, etc.) and flagging incompatibilities or obligations
• Outdated dependencies: Highlighting components that are multiple versions behind, increasing upgrade difficulty
• Maintainer risk: Flagging dependencies with single maintainers or inactive repositories
• Supply chain security: Detecting dependency confusion attacks, typosquatting, and compromised packages

SCA in practice

Effective SCA requires integration with development workflows. Running SCA only in production is too late—by then, vulnerable dependencies are already deployed. Modern SCA tools integrate with:

• CI/CD pipelines to block merges introducing vulnerable dependencies
• IDE plugins for immediate feedback during development
• Container registries to scan images before deployment

See also: CVE, CWE, Supply Chain Security, SAST