Hi everyone! I'm pretty new to the whole application security world, coming from email marketing. All this scanner talk has me a bit lost.
I keep seeing "static" (SAST) and "dynamic" (DAST) mentioned. I get that one looks at code and the other tests a running app, but what does that actually mean for finding bugs? Like, would a static scan catch a login flaw, and a dynamic scan find it? Trying to picture the real workflow difference. Any simple examples would be awesome! 😊
SAST catches a login flaw like hardcoded credentials or SQL injection in the source code before it runs. DAST would catch the same flaw by actually trying to log in with a malicious payload or checking if you can bypass authentication on the live app.
The key difference is cost. Fixing a login bug in a static scan costs you developer time before deploy. Fixing it after DAST finds it in production means re-deploying, potential downtime, and possibly a breach report. SAST false positives waste time. DAST misses code paths you didn't exercise. So you run both, but the ROI shifts depending on your pipeline maturity.
For a concrete example: SAST sees `if (password == "admin123")` in the code. DAST sees that the login page accepts `admin123` and returns a session token. Which one hurts more when it goes live?
cost per transaction is the only metric
That cost angle hits home for us. We started with SAST in the pipeline because it felt like the right thing. The false positives were brutal - wasted so many cycles chasing things that weren't real in production. But you're right, even one real catch before it ships saves a huge headache.
Your ROI point makes me wonder, for a small team with limited time, is it better to prioritize tuning SAST to reduce noise, or just accept some noise to catch the big things early? We're leaning toward the latter now, even with the false positives, because redeploying is such a pain.
Think of it like checking a recipe vs tasting the finished soup.
Static (SAST) reads the recipe line by line. It can flag if you wrote "add 10 tablespoons of salt," because that's obviously wrong on paper. It finds flaws in the instructions.
Dynamic (DAST) tastes the soup. It doesn't care about the recipe; it tries to eat the soup. Maybe you forgot to list an ingredient that causes an allergy, but the soup still has it. DAST finds that by interacting with the actual, cooked dish.
For your login example: SAST might catch the insecure code pattern. DAST actually tries to log in with "admin" or ' OR '1'='1 to see if it works.
You kinda need both, because you can have a perfect recipe (SAST passes) that still produces bland soup (DAST finds issues in the live mix).
Spreadsheets > marketing slides.