Dynamic Application Security Testing (DAST)
Part of the Cybersecurity Roadmap
In short
DAST tests your app while it runs, poking at live endpoints the way an attacker would from outside. It catches problems that only show up once everything is wired together.
Testing a running application from the outside, simulating real attacks against live endpoints — catches runtime issues SAST can't see, at the cost of needing a running environment to test against.
Think of it like this
Rattling every door of the finished house
Blueprints look perfect, but a careful inspector still walks the finished house and tries every door and window to see which actually locks. DAST is that inspector: it tests the running application from the outside, finding what the plans could not reveal.
Watch it happen
DAST probes a running app
crawl endpoints
1/4The tool maps the running app, finding its pages, forms and APIs.
The big ideas
What you need to know
Tests the live app
DAST runs against a running target, so it sees real behaviour that static code review cannot.
Attacker's view
It probes from the outside with no source code, much like a real external attacker would.
Runs later
You need a deployed, running version to test, so DAST fits staging and pre production stages.
Test safe targets only
Run DAST against your own staging or lab app, never a system you do not own or have permission to test.
Save yourself the pain
Common mistakes
Oops
Pointing a DAST scanner at any website to try it out.
Do this instead
Only scan apps you own or have written permission to test. Scanning others' systems is illegal.
Oops
Expecting DAST to find every code level bug.
Do this instead
It only sees what it can reach at runtime. Pair it with SAST, which reads the source it cannot observe.
Your mission
Scan a deliberately vulnerable app
Quick check
Why does DAST need a running version of the application?
Go deeper
- 1Run a free DAST tool (like OWASP ZAP) against a legal practice web application.
- 2Learn the trade-off: DAST tests real behavior but can't see the source code directly.
- 3Understand why SAST and DAST together catch a broader range of issues than either alone.
More topics at this stop
Secure SDLC ('Shift Left')
Threat Modeling
Static Application Security Testing (SAST)
Software Composition Analysis (SCA)
API Security
Secure Code Review
Security Champions Programs
DevSecOps Practices
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