Software Composition Analysis (SCA): What It Is and How SBOMs Fit In

Software Composition Analysis (SCA) is a category of application security tooling that identifies open source and third-party components in a codebase, catalogs their licenses, and detects known vulnerabilities associated with those components. SCA tools work by analyzing dependency manifests, lock files, and sometimes compiled binaries to produce an inventory of components that can be matched against vulnerability databases like the National Vulnerability Database (NVD) and the CISA KEV catalog.

What Is Software Composition Analysis?

Software Composition Analysis addresses a fundamental reality of modern software development: most applications are not written from scratch. Studies consistently show that 70-90% of a typical application consists of open source components pulled from package registries like npm, PyPI, Maven Central, and crates.io. Each of these components introduces potential security vulnerabilities, license obligations, and maintenance risks.

SCA tools automate the process of identifying these components and their associated risks. Without SCA, development teams would need to manually track every library version across every project — an approach that does not scale given the pace of vulnerability disclosure (the NVD published over 28,000 CVEs in 2023 alone).

The core functions of SCA are:

1. Component identification. Scanning source code, dependency files, and sometimes binaries to produce a complete inventory of third-party components, including transitive dependencies — the dependencies of your dependencies.
2. Vulnerability detection. Matching identified components against vulnerability databases to flag known CVEs.
3. License compliance. Identifying the license of each component and flagging potential conflicts or compliance obligations, such as GPL copyleft requirements.
4. Policy enforcement. Allowing organizations to define rules (e.g., “block any component with a critical CVE” or “reject AGPL-licensed dependencies”) and enforce them in CI/CD pipelines.

How SCA Tools Work

SCA tools typically operate through one or more of these analysis methods:

Manifest and Lock File Analysis

The most common approach. SCA tools parse dependency declaration files — package.json and package-lock.json (JavaScript), requirements.txt and poetry.lock (Python), pom.xml (Java), go.sum (Go), Cargo.lock (Rust), and similar files for other ecosystems. This provides a definitive list of declared dependencies and their resolved versions.

Source Code Scanning

Some SCA tools scan source code files to detect component usage that may not be declared in manifests — for example, vendored code (source files copied directly into a repository rather than managed through a package manager), or code snippets pulled from Stack Overflow or other sources.

Binary Analysis

Binary SCA analyzes compiled artifacts (executables, container images, firmware) to identify embedded components. This is essential when source code is not available, such as when evaluating third-party commercial software or auditing firmware. Binary analysis is less precise than manifest analysis but covers a broader set of use cases.

Dependency Resolution

Advanced SCA tools resolve the full dependency tree, including transitive dependencies. A project that declares 10 direct dependencies may actually depend on hundreds of transitive packages. SCA tools that only examine direct dependencies miss the majority of the attack surface.

SCA vs. SAST vs. DAST

SCA is one of several application security testing approaches. Each addresses different risk categories and operates at different points in the software development life cycle.

These tools are complementary. A comprehensive application security program uses all three:

• SCA catches known vulnerabilities in the 70-90% of your application that you did not write
• SAST catches coding flaws in the 10-30% that you did write
• DAST catches runtime issues that only manifest in a deployed environment

SCA Tools

Several tools provide SCA capabilities. The ecosystem spans open source and commercial offerings.

Open Source SCA Tools

• Grype — Vulnerability scanner from Anchore that matches SBOMs and container images against vulnerability databases. Works well in combination with Syft for SBOM generation.
• OWASP Dependency-Check — Mature OWASP project that identifies project dependencies and checks for known CVEs. Supports Java, .NET, JavaScript, Ruby, and Python.
• OWASP Dependency-Track — Continuous SBOM analysis platform that ingests SBOMs and monitors components against multiple vulnerability databases. Provides a dashboard for tracking risk across an entire portfolio.
• OSV-Scanner — Google’s open source vulnerability scanner that uses the OSV database and supports multiple ecosystems.
• Trivy — Comprehensive scanner from Aqua Security that detects vulnerabilities in OS packages, language dependencies, container images, and IaC configurations.

Commercial SCA Tools

• Snyk Open Source — Developer-focused SCA with IDE integrations and automated fix PRs
• Sonatype Lifecycle — Enterprise SCA with policy engine and supply chain firewall
• Black Duck (Synopsys) — Enterprise SCA with extensive binary analysis capabilities
• FOSSA — SCA focused on license compliance and open source management

For a comprehensive list of tools in the SBOM ecosystem, see our resources page.

SCA and SBOMs

SCA tools and SBOMs are closely related but serve different purposes. Understanding the relationship helps you build a more effective security program.

SCA Generates SBOMs

Many SCA tools produce SBOMs as an output of their analysis. The sbomify GitHub Action generates SBOMs and automatically enriches them with license, hash, and lifecycle metadata from 11+ data sources. Standalone tools like Syft and Trivy also generate SBOMs in standard formats (CycloneDX or SPDX). In this sense, SCA is one of the primary methods for SBOM generation.

SBOMs Enable Continuous SCA

A generated SBOM can be ingested by management platforms like sbomify or OWASP Dependency-Track for continuous analysis. Instead of re-scanning your entire codebase every time a new CVE is published, the platform matches new vulnerabilities against your existing SBOM inventory. This is particularly valuable for monitoring production deployments where source code may not be readily accessible.

SBOMs Go Beyond SCA

While SCA focuses on vulnerability detection and license compliance, SBOMs serve a broader purpose:

• Regulatory compliance. Frameworks like Executive Order 14028, the EU Cyber Resilience Act, and FDA medical device guidance require SBOMs as a compliance artifact — not just SCA scan results.
• Supply chain transparency. SBOMs document the provenance and composition of software for consumers, auditors, and regulators.
• Incident response. When a vulnerability like Log4Shell is disclosed, SBOMs allow you to immediately identify affected products without re-running scans.

For organizations building a security program, SCA tools are the engine and SBOMs are the artifact. Use SCA to scan and detect; use SBOMs to document, share, and continuously monitor.

Best Practices

1. Integrate SCA into CI/CD. Run SCA scans on every build and pull request. Catching vulnerable dependencies before they reach production is far less costly than remediating them after deployment.

2. Monitor continuously, not just at build time. New vulnerabilities are disclosed daily. Use SBOM-based monitoring with platforms like sbomify or OWASP Dependency-Track to catch newly disclosed CVEs in your already-deployed components.

3. Resolve the full dependency tree. Ensure your SCA tool analyzes transitive dependencies, not just direct ones. The majority of vulnerable components in most projects are transitive.

4. Define and enforce policies. Establish clear rules for vulnerability severity thresholds, license restrictions, and acceptable risk. Automate enforcement in your pipeline to prevent policy violations from reaching production.

5. Combine SCA with SAST and DAST. SCA only finds known vulnerabilities in third-party code. Pair it with SAST for your own code and DAST for runtime testing to cover all three risk categories.

6. Generate SBOMs from SCA output. Use your SCA tool’s SBOM generation capability to produce machine-readable component inventories in CycloneDX or SPDX format. These SBOMs serve both security monitoring and compliance purposes.

Frequently Asked Questions

What is software composition analysis?

Software Composition Analysis (SCA) is a category of security tooling that identifies open source and third-party components in your software, detects known vulnerabilities in those components by matching them against databases like the NVD, and catalogs their licenses for compliance purposes. SCA tools analyze dependency manifests, lock files, and sometimes binaries to produce a complete component inventory.

What is the difference between SCA and SAST?

SCA analyzes third-party and open source components in your application for known vulnerabilities and license issues. SAST (Static Application Security Testing) analyzes your own source code for coding flaws like injection vulnerabilities, authentication bypasses, and logic errors. SCA covers the 70-90% of your application that is third-party code; SAST covers the code you wrote yourself. Both are needed for comprehensive application security.

How does SCA relate to SBOMs?

SCA tools are one of the primary methods for generating SBOMs. When an SCA tool scans your project and identifies all components, that inventory can be exported as an SBOM in standard formats like CycloneDX or SPDX. Conversely, SBOMs enable continuous SCA by providing a persistent component inventory that can be monitored against new vulnerability disclosures without re-scanning source code.

What are the best open source SCA tools?

Leading open source SCA tools include Grype (vulnerability scanner from Anchore), OWASP Dependency-Track (continuous SBOM analysis platform), OWASP Dependency-Check (mature CVE detection tool), OSV-Scanner (Google’s vulnerability scanner using the OSV database), and Trivy (comprehensive scanner from Aqua Security). Choice depends on your ecosystem, integration requirements, and whether you need CLI scanning, CI/CD integration, or continuous monitoring.

Does SCA find all vulnerabilities?

No. SCA finds known vulnerabilities in third-party components — those that have been assigned CVE identifiers and added to vulnerability databases. It does not find zero-day vulnerabilities (those not yet publicly known), vulnerabilities in your own code, or runtime configuration issues. SCA should be combined with SAST, DAST, and penetration testing for comprehensive coverage.