Introduction
When it comes to securing applications, two terms come up often: SAST and DAST. Both are types of security testing — but they work in different ways, at different stages.
Let’s explore how they compare.
1. What is SAST? (Static Application Security Testing)
SAST analyzes your code without executing it.
- It scans the source code, bytecode, or binaries
- Typically runs early in the development process (shift left)
- Helps identify vulnerabilities like SQL injection, XSS, hardcoded secrets, etc.
Think of it like a spellchecker for your code.
🛠 Common tools: SonarQube, Semgrep, Checkmarx, Snyk Code
2. What is DAST? (Dynamic Application Security Testing)
DAST analyzes a running application.
- It tests the app in real-time (usually in staging or QA)
- Doesn’t require access to source code
- Simulates attacks from the outside — like a black box test
Think of it like hiring a robot hacker to test your app.
🛠 Common tools: OWASP ZAP, Burp Suite, StackHawk
3. Key Differences Between SAST and DAST
| Feature | SAST | DAST |
|---|---|---|
| Type of test | Static | Dynamic |
| Runs on | Source code | Running application |
| Timing | Early in pipeline | Later in pipeline (QA/Staging) |
| Visibility | Code-level insights | Runtime behavior & responses |
| Use case | Find bugs before build | Find runtime issues before prod |
4. Do you need both?
Yes. SAST and DAST are complementary.
- SAST helps developers catch issues early
- DAST helps security teams catch issues in live environments
Together, they form a more complete AppSec strategy.
Conclusion
SAST scans your code; DAST scans your app in action. Using both helps catch more vulnerabilities at every stage of development.
That’s SAST vs DAST.