SAST vs DAST: Choosing the Right Security Testing Approach
SAST and DAST are the two foundational approaches to application security testing. They find different types of vulnerabilities at different stages of development. Understanding when to use each — and why you need both — is essential for a complete security strategy.
Head-to-Head Comparison
| Feature | SAST | DAST |
|---|---|---|
| What it tests | Source code, bytecode, binaries | Running application (HTTP/API) |
| Testing approach | White-box (sees code) | Black-box (no code access) |
| When in SDLC | During development (shift-left) | After deployment (staging/prod) |
| Finds | SQL injection, XSS, hardcoded secrets, buffer overflows, insecure crypto | Auth issues, misconfigurations, SSL/TLS problems, CORS, business logic |
| Coverage | All code paths (including dead code) | Only reachable/crawlable endpoints |
| False positives | Higher without AI (O360 AI reduces significantly) | Lower (validates exploitability) |
| Language dependency | Yes — needs language support | No — language agnostic |
| Fix guidance | Exact line of code + AI-generated fix | Endpoint and payload info |
| Requires | Source code access | Running application URL |
| Speed | Minutes to hours (depends on codebase size) | Hours to days (depends on app complexity) |
When to Use SAST
- You want to find vulnerabilities before deployment
- You need to scan every commit in CI/CD
- You want exact code locations and AI-generated fixes
- You need to analyze all code paths, including error handlers and edge cases
- You are developing in languages with memory safety concerns (C, C++)
When to Use DAST
- You want to validate vulnerabilities are actually exploitable
- You need to test deployed configurations (SSL, headers, CORS)
- You want to find authentication and session management issues
- You are testing third-party applications without source code access
- You need to test API security (REST, GraphQL, SOAP)
The Answer: Use Both
SAST and DAST are complementary. The most secure organizations use both:
- SAST in CI/CD — Scan every pull request. Block merges with critical vulnerabilities.
- DAST in staging — Test deployed application before production release.
- SAST + SCA together — Cover both custom code and open-source dependencies.
O360 provides SAST, DAST, and SCA in a single platform with unified reporting, so you get complete coverage without managing multiple tools.
Learn More
What is SAST? | What is DAST? | What is SCA? | What is DevSecOps?