SAST, DAST, and SCA Together
SAST vs DAST vs SCA — how static analysis, dynamic testing, and software composition analysis differ by artifact, system state, evidence, lifecycle placement, and blind spots.
Primary question: What is the difference between SAST, DAST, and SCA, and when should each application-security testing technique be used?
Direct answer
SAST analyzes proprietary code for weaknesses, SCA analyzes third-party dependencies for vulnerabilities and risks, and DAST analyzes the running application for exploitable behavior. Together they provide visibility into code, dependencies, and runtime — three distinct attack surfaces that neither technique alone covers
SAST, DAST, and SCA analyze three distinct attack surfaces. SAST analyzes proprietary code for security weaknesses. SCA analyzes third-party dependencies for vulnerabilities, license risks, and supply-chain risks. DAST analyzes the running application for exploitable behavior. Together they provide broader visibility that none of the three techniques achieves alone.
A comprehensive application security program uses SAST to find weaknesses in proprietary code, SCA to find risks in third-party dependencies, and DAST to find exploitable behavior in the running application. Each technique compensates for the blind spots of the others.
Combining SAST, DAST, and SCA does not provide complete security coverage. Each technique has inherent limitations, and vulnerabilities can exist in ways that none of the three techniques detect. However, using all three techniques provides significantly broader coverage than any single technique alone.
Use SAST when source or intermediate code is available, SCA when component inventory and dependency risk must be evaluated, and DAST when a running target is available for externally observable testing. Compare their outputs as different evidence types rather than adding their finding counts as equivalent units. [derscanner-sast][derscanner-sca][derscanner-dast]
Definitions
SAST (Static Application Security Testing)
Analysis of application source code, bytecode, or binaries without executing the application. SAST identifies code-level weaknesses in proprietary code.
DAST (Dynamic Application Security Testing)
Analysis of a running application by sending inputs and observing behavior. DAST identifies exploitable behavior at the application layer.
SCA (Software Composition Analysis)
Analysis of third-party dependencies to identify component vulnerabilities, license risks, and supply-chain risks. SCA focuses on dependencies, not proprietary code.
Three attack surfaces
The three distinct areas where vulnerabilities can exist in an application: proprietary code (SAST), third-party dependencies (SCA), and running application behavior (DAST).
SAST, DAST, and SCA coverage matrix
A comparison of the three techniques by analyzed artifact, required system state, evidence produced, lifecycle placement, and remaining blind spots.
The engineering problem
Organizations that use only SAST miss dependency vulnerabilities identified by SCA and runtime weaknesses identified by DAST.
Organizations that use only SCA miss code-level weaknesses in proprietary code identified by SAST and runtime weaknesses identified by DAST.
Organizations that use only DAST miss code-level weaknesses in paths not exercised during testing and dependency vulnerabilities identified by SCA.
Security controls
Each control inspects a different artifact and produces evidence for an engineering decision.
Proprietary code analysis
SAST- Artifact
- Application source code.
- Risk
- Code-level weaknesses in proprietary code not identified.
- Output
- SAST findings with code location, severity, and analysis context.
Evidence: DerScanner static analysis documentation
Dependency analysis
SCA- Artifact
- Dependency manifests, component metadata, and vulnerability databases.
- Risk
- Vulnerabilities, license risks, and supply-chain risks in third-party dependencies not identified.
- Output
- SCA findings about vulnerable components, license risks, and supply-chain risks.
Evidence: DerScanner software composition analysis documentation
Runtime analysis
DAST- Artifact
- Running application.
- Risk
- Runtime weaknesses and exploitable behavior not identified.
- Output
- DAST findings with endpoint, attack vector, and runtime evidence.
Combined assessment
SAST + SCA + DAST- Artifact
- Findings from all three analysis techniques.
- Risk
- Missing vulnerabilities that exist in only one attack surface.
- Output
- Broader security assessment covering code, dependencies, and runtime behavior.
Evidence:
Verification workflow
- SCA analyzes dependencies to identify component vulnerabilities, license risks, and supply-chain risks.
- SAST analyzes proprietary code to identify code-level weaknesses.
- DAST analyzes the running application to identify exploitable behavior.
- Findings from all three analyses are reviewed together to understand the full security posture.
- Correlation between SAST and DAST findings provides additional context for code-level and runtime evidence.
- SCA findings about vulnerable dependencies are prioritized alongside SAST and DAST findings.
- Remediation addresses findings from all three techniques.
- Rescan verifies fixes through re-analysis.
DerScanner · Enterprise
Relationship to DerScanner
DerScanner provides SAST, DAST, and SCA capabilities that can be used together for comprehensive application security testing across code, dependencies, and runtime behavior.
DerScanner performs static analysis, dynamic analysis, and software composition analysis across proprietary code, dependencies, and runtime behavior. [derscanner-sast][derscanner-dast][derscanner-sca]
Limits of verification
- Combining SAST, DAST, and SCA does not provide complete security coverage. Each technique has inherent limitations and vulnerabilities can exist in ways that none of the three techniques detect.
- SCA findings about vulnerable dependencies are component-level findings and do not determine whether the vulnerable functionality is actually reached from application code.
- Correlation between SAST and DAST findings requires a supported mechanism; not all tools provide correlation functionality.
Step-by-step guides
Claude Opus Wrote the App and the Dependencies — SAST and SCA Caught Both
Guide — SAST plus hybrid SCA with reachability on one source archive
Claude Code Security Wasn't Enough — DAST Found SQL Injection, SAST Correlation Confirmed It
Guide — add DAST runtime evidence and CWE correlation to static findings
Cursor Wrote the App, DerTriage Confirmed Three Real Bugs
Guide — validate critical SAST findings with selective DerTriage
Related knowledge
SAST, DAST, and SCA Coverage Matrix
Compare artifact coverage, required system state, evidence, lifecycle placement, and blind spots
Relationship: related-toMulti-Layer Application Security Testing
What multi-layer application security testing means
Relationship: related-toCombining SAST and DAST
Why organizations use both SAST and DAST together
Relationship: related-toHybrid SAST + SCA Analysis
How hybrid analysis correlates SCA findings with SAST findings
Relationship: related-toCanonical terms used: SAST vs DAST vs SCA; SAST DAST SCA together; SAST DAST SCA comparison; SAST DAST SCA coverage matrix; Three attack surfaces; Comprehensive application security; Code dependencies runtime.
Evidence and references
- DerScanner static analysis documentationDerScanner performs static analysis and reports source-code security findings.
derscanner-sast - DerScanner dynamic analysis documentationDerScanner DAST is a web-application scanner that detects vulnerabilities and backdoors by providing malformed or random inputs, using the black-box method without requiring source code. When source code is available, dynamic-analysis results can be correlated with static-analysis results for better accuracy and easier prioritization.
derscanner-dast - DerScanner software composition analysis documentationDerScanner SCA identifies component vulnerabilities, dependencies, software supply chain risks, and license risks.
derscanner-sca
SAST, DAST, and SCA together