Dynamic Application Security Testing (DAST) tests running applications for security vulnerabilities by simulating attacks. Learn how it works and why it's essential.
DAST (Dynamic Application Security Testing) is a black-box testing method that examines applications while they're running. It simulates real-world attacks against your live application to find vulnerabilities that only exist at runtime.
A simulated attacker probing your live application from the outside. It doesn't know your source code—it only sees what users see, finding vulnerabilities the same way hackers would.
The DAST tool crawls your application like a search engine, discovering pages, forms, APIs, and other entry points.
Sends malicious payloads to each discovered input: SQL injection strings, XSS payloads, authentication bypasses, and more.
Analyzes application responses for signs of vulnerability: error messages, unexpected behavior, successful payload reflection.
Confirms vulnerabilities are exploitable and generates reports with reproduction steps and remediation guidance.
Database manipulation through input fields
Script injection in rendered pages
Accessing protected resources without proper login
Session fixation, hijacking, token issues
Exposed headers, verbose errors, defaults
Accessing other users' data (IDOR)
HSTS, CSP, X-Frame-Options not set
Weak ciphers, certificate problems
| Aspect | DAST | SAST |
|---|---|---|
| Testing Type | Black-box (running app) | White-box (source code) |
| When Used | After deployment | During development |
| Requires | Running application URL | Source code access |
| Finds | Runtime vulnerabilities | Code-level vulnerabilities |
| False Positives | Less common | More common |
| Remediation Info | URL/endpoint | Exact line number |
Best Practice: Use both SAST and DAST together. SAST finds issues early in the code; DAST validates the running application is secure.
Open Source
Best for: Free, extensible
Freemium
Best for: Manual testing
Open Source
Best for: Template-based
Commercial
Best for: Full automation
Commercial
Best for: Enterprise scale
Commercial
Best for: IBM integration
DAST can potentially cause issues if it creates test data, triggers rate limits, or tests destructive endpoints. Run DAST in staging environments when possible, or use safe mode options.
Most DAST tools support recorded authentication sequences, API tokens, or session cookies. Configure authentication so the scanner can test protected functionality.
Run DAST scans after each deployment to staging/production, at minimum weekly. Include in CI/CD for continuous security validation.
Yes, but SPAs need special handling (JavaScript execution). APIs work well with DAST—provide OpenAPI/Swagger specs for better coverage.
Find vulnerabilities in your deployed application before attackers do.
Scan Your App FreeLast updated: January 2025