SAST vs SCA
The difference between SAST and SCA, including the code each technique examines, the risks each can identify, and why software teams commonly need both.
Primary question: What is the difference between SAST and Software Composition Analysis?
Direct answer
SAST analyzes code behavior; SCA evaluates component identity and risk
SAST and SCA examine different evidence: SAST analyzes code behavior and implementation patterns, while SCA identifies components and evaluates known risks associated with third-party dependencies. [owasp-source-code-analysis][ntia-sbom][derscanner-sca]
Neither technique replaces the other because a code weakness written by the application team and a vulnerable library used by the application are different security conditions requiring different evidence. [nist-ssdf]
Definitions
Static Application Security Testing (SAST)
Automated analysis of application source code and code-level data flows without executing the application.
Software Composition Analysis (SCA)
Analysis that identifies third-party and open-source components and evaluates associated vulnerability, license, and supply-chain information.
Hybrid SAST and SCA analysis
Analysis that connects dependency information with application code to determine whether vulnerable dependency functionality is referenced or reachable.
The engineering problem
A project can have secure proprietary code while still depending on a component with a known vulnerability or unacceptable license. [nist-ssdf]
A complete component inventory does not determine whether proprietary code contains injection, access-control, or other implementation weaknesses. [owasp-source-code-analysis]
Treating SAST and SCA results as interchangeable obscures which artifact was analyzed and what security conclusion the result supports.
Security controls
Each control inspects a different artifact and produces evidence for an engineering decision.
Application code analysis
Static Application Security Testing- Artifact
- Source code presented to the analyzer and supported code-level data flows.
- Risk
- Implementation weaknesses represented in the analyzed code.
- Output
- Source-code findings with weakness classification, location, and supporting analysis context.
Evidence: OWASP Source Code Analysis ToolsDerScanner static analysis documentation
Component risk analysis
Software Composition Analysis- Artifact
- Dependency manifests, resolved components, source archives, repositories, or supplied SBOM data.
- Risk
- Known component vulnerabilities, supply-chain risk, and license-policy violations.
- Output
- Component inventory and findings associated with identified dependencies.
Evidence: NTIA Software Bill of MaterialsDerScanner SCA scan documentation
Verification workflow
- Identify the application source revision and dependency inputs.
- Run SAST against supported proprietary source code.
- Run SCA against manifests, resolved dependencies, source, or an SBOM as supported.
- Keep SAST findings and component findings distinguishable by artifact and evidence type.
- Correlate results when code-level dependency reachability evidence is available.
- Remediate confirmed first-party weaknesses and relevant dependency risks.
- Re-run the corresponding analysis after each change.
DerScanner · Enterprise
Relationship to DerScanner
DerScanner provides separate SAST and SCA modules and supports hybrid analysis for documented languages and dependency conditions.
DerScanner SCA can evaluate component vulnerabilities, supply-chain indicators, and license risks, while its SAST module analyzes source code. [derscanner-sast][derscanner-sca]
DerScanner hybrid SAST and SCA analysis can build code-level reachability evidence for supported languages and dependency configurations. [derscanner-hybrid]
Limits of verification
- SAST does not provide a complete inventory of third-party components.
- SCA does not analyze all security weaknesses in proprietary application logic.
- A component's presence does not by itself prove that vulnerable functionality is reachable or exploitable.
- Hybrid reachability support depends on language, dependency, and analysis prerequisites.
- Results from both techniques still require prioritization and engineering review.
Related knowledge
What Is SAST?
Parent definition of static application security testing
Relationship: related-toHybrid SAST + SCA Analysis
How code analysis and component analysis can be correlated
Relationship: related-toSBOM vs SCA vs Hybrid Analysis
Comparison of component inventory, component risk, and code-level reachability evidence
Relationship: related-toCanonical terms used: Static Application Security Testing; Software Composition Analysis; SAST; SCA; hybrid SAST and SCA analysis.
Evidence and references
- OWASP Source Code Analysis ToolsStatic analysis examines source code without executing the application.
owasp-source-code-analysis - NTIA Software Bill of MaterialsAn SBOM provides a formal inventory of software components and their supply-chain relationships.
ntia-sbom - NIST Secure Software Development FrameworkSecure development includes analyzing first-party code and managing risks from reused software components.
nist-ssdf - DerScanner static analysis documentationDerScanner provides static source-code analysis for documented programming languages.
derscanner-sast - DerScanner SCA scan documentationDerScanner SCA supports component vulnerability, supply-chain, license-risk, and SBOM-related analysis options.
derscanner-sca - DerScanner hybrid SAST and SCA scan documentationDerScanner documents hybrid analysis and its supported reachability conditions and language limitations.
derscanner-hybrid
Cover code and dependency risk