🛡️ SAST vs DAST Scans
These are two common approaches to application security testing.
1️⃣ SAST – Static Application Security Testing
Definition:
SAST analyzes source code, bytecode, or binaries without running the application to find security vulnerabilities.
Key Points:
- Static testing: No runtime execution.
- Detects vulnerabilities early in development (Shift-Left approach).
- Examples: SQL Injection, XSS in code, insecure configurations.
How it works:
Developer writes code → SAST tool scans code → Reports vulnerabilities → Fix code
Pros:
- Early detection → cheaper to fix.
- Can be integrated into CI/CD pipeline.
Cons:
- Might produce false positives.
- Cannot detect runtime issues like environment misconfigurations.
Example tools: SonarQube, Checkmarx, Fortify, Veracode.
2️⃣ DAST – Dynamic Application Security Testing
Definition:
DAST analyzes a running application by simulating attacks to find security weaknesses.
Key Points:
- Dynamic testing: Application is executed.
- Works like a black-box tester: does not require source code.
- Detects runtime vulnerabilities: authentication issues, input validation errors, session management flaws.
How it works:
App deployed → DAST tool attacks endpoints → Finds vulnerabilities → Report → Fix
Pros:
- Realistic testing (finds runtime issues).
- Can detect misconfigurations and environment-related vulnerabilities.
Cons:
- Late detection (after code is written/deployed).
- Might miss deep code vulnerabilities not exposed in runtime.
Example tools: OWASP ZAP, Burp Suite, AppSpider, Netsparker.
3️⃣ SAST vs DAST – Quick Comparison
| Feature | SAST | DAST |
|---|---|---|
| Stage | Early (development) | Late (running app) |
| Testing method | Static (code review) | Dynamic (runtime) |
| Access to code | Yes | No |
| Types of issues found | Code flaws, SQLi, XSS | Runtime flaws, auth issues, misconfigurations |
| False positives | Higher | Lower (more realistic) |
| CI/CD integration | Easy | Possible, but slower |
4️⃣ Combined Approach (Best Practice)
- Shift-Left: Use SAST early in development.
- Pre-Release: Use DAST on staging/QA environment.
- Continuous Security: Integrate both in CI/CD pipeline for maximum coverage.
💡 Analogy:
- SAST: Reading a blueprint to spot design flaws before construction.
- DAST: Inspecting the building by trying to break doors/windows after construction.