Hey folks, I'm deep in a security tool evaluation for our marketing tech stack (we build a lot of custom landing page tools and internal apps). We're pretty set on getting a SAST solution like Checkmarx to bake into our CI/CD pipeline. It makes total sense to catch vulnerabilities at the code level early.
But now I'm hearing about DAST, and I'm trying to figure out if it's just overlap or if it brings something unique to the table. If SAST scans the source code, doesn't that cover it? I'm looking at this from a practical, budget-and-resources angle.
For context, our team pushes updates frequently, and we handle customer PII in some of our lead capture flows. My gut says they complement each other, but I need to justify the potential added cost and complexity. Has anyone run both? What specific gaps did DAST catch that SAST missed for you? Real-world examples would be super helpful.
Your gut's right, they complement each other. SAST won't catch runtime issues, misconfigurations in your deployed environment, or problems with third-party services your app calls. Since you're handling PII, that's huge.
We ran both last year and DAST flagged a real doozy SAST missed: an authentication bypass that only surfaced because our staging environment had slightly different session cookie settings than local dev. The code was "secure," but the live config wasn't.
For frequent updates, maybe start with SAST in CI/CD and run DAST on a nightly scan against a staging environment? That can balance coverage with cost. The complexity is less about tools and more about triaging the combined findings.
SAST is static analysis, which means it's reasoning about the code's *potential* states. DAST tests the *actual* running application state. That's the core distinction, and it creates a blind spot for anything dependent on the runtime environment.
Since you're building custom landing pages and handling PII, here's a concrete gap: SAST will likely miss issues stemming from your specific deployment. For example, if your web server (nginx, Apache) in staging or production is configured with insecure headers that override your code's intentions, SAST can't see that. A misconfigured Content Security Policy or missing security headers on your lead capture forms would be invisible.
Another real-world example we logged: a third-party JavaScript library loaded from a CDN had a later-stage vulnerability. The SAST scan on our source code passed because the library reference itself was just a URL string. The DAST scan, hitting the live application, identified the vulnerable version being served. DAST also caught a logic flaw where a specific sequence of actions (submit form, browser back button, modify hidden field) allowed data manipulation, which static analysis couldn't reconstruct.
For budget justification, frame DAST as testing the actual attack surface, not the theoretical one. The cost of a single PII incident likely dwarfs the tooling. You can start with scheduled DAST on a staging environment that mirrors production configs, which is less disruptive than trying to integrate it into every pipeline commit.
benchmarks or bust
You're right to think about overlap, but the other comments nailed the runtime gap. Since you mentioned landing pages and PII, I'll add a data pipeline angle that bit me.
We had a similar setup and SAST missed a vulnerability where user input from a lead capture form was logged (for analytics) before being redacted. The code looked fine because the redaction function was called, but the logging happened first in the actual execution flow. DAST caught it because it saw the raw data in a test log file that the running app created. SAST just saw a call to a "safe" function.
For frequent updates, how do you handle the staging environment syncing? If DAST runs nightly, is your staging branch always production-like? I'm nervous about drift making the DAST results less useful.
Totally get the budget angle, we had the same debate. Since you're building landing pages with PII, think about the final render. SAST won't see issues in the live DOM, like form data accidentally exposed in a browser's autocomplete because of a missing attribute. That's a runtime context thing.
We also found DAST caught problems with our third-party marketing scripts. The code we wrote was clean, but a script from our analytics provider was pulling in a vulnerable library version on the client side. SAST only scans your source.
For frequent updates, could you run DAST on a subset of critical paths, maybe just the PII handling flows, to keep scan times and costs down? That's how we made it workable.
automate the boring stuff
That authentication bypass example is really good. It shows how the environment itself can be the problem, not the code.
So DAST is basically a check against our actual staging/prod setup? That makes sense for catching config drift.
But how do you manage the "slightly different" staging environment problem? If our staging config is wrong, does that mean DAST might flag something that isn't an issue in prod, or miss something that is?
Still learning