Published · By the Aesparrow Security Research Team
Short answer
SAST (static application security testing) analyses your own source code for insecure patterns; DAST (dynamic application security testing) attacks the running application from outside; SCA (software composition analysis) inventories open-source dependencies and flags known vulnerabilities and licence risks. They find different problems, so mature DevSecOps programmes use all three plus periodic manual penetration testing.
How do SAST, DAST and SCA compare?
| SAST | DAST | SCA | |
|---|---|---|---|
| What it tests | Your source code | Running application | Third-party components |
| When | Commit / pull request | Staging / pre-release | Every build |
| Finds | Insecure code patterns | Runtime and config flaws | Known CVEs, licence risk |
| Misses | Runtime and logic issues | Code-level root cause | Flaws in your own code |
| Output | File and line references | Vulnerable URLs and requests | SBOM and upgrade paths |
Why is SCA important?
Most modern applications are built largely from open-source packages, so vulnerable dependencies are a major attack route. The Verizon 2025 DBIR reported that breaches involving third parties doubled to 30%. SCA gives you a software bill of materials (SBOM) and alerts you as soon as a component you use gets a new CVE.
Where does penetration testing fit?
Automated tools cannot understand business logic or chain issues together. A manual penetration test validates what automation finds and catches authorisation and logic flaws, so it remains essential alongside SAST, DAST and SCA.