Dynamic Application Security Testing (DAST) is a well-established practice, but there’s a reason it’s been around so long and all but become a cornerstone in AppSec. However, DAST, like any approach, is only as good as the person wielding it and applying it in the right context. After all, a hammer is best used if you have a nail, but if you don’t have a blueprint, you don’t know what you’re even building in the first place. With that, let’s dive right into the world of DAST, what it is, and what it isn’t.
What’s the Deal with DAST?
First things first, what even is DAST? Simply put, DAST is like a security detective investigating your applications by simulating real-world cyberattacks and hunting for vulnerabilities while your apps are running. Think of it as a controlled “hack” that finds weaknesses before the bad guys do.
Now, what DAST isn’t: It isn’t magic, and it definitely isn’t a “set it and forget it” solution. Unlike Static Application Security Testing (SAST), which explores source code, DAST looks at apps from the outside in runtime with no visibility at the actual code lines.
In the context of cybersecurity, SAST examines the pieces in isolation (the code itself), while DAST tests the running application as it functions in real-world scenarios.
Real-World Benefits of DAST
Speaking of the real-world, let’s talk about real benefits. Why should you add DAST to your security toolkit?
Today, developers are throwing together apps faster than ever, using APIs, containers, proprietary code, and even open-source software. But rapid development can also lead to hidden vulnerabilities sneaking in.
Enter DAST. It doesn’t care about your source code. It dives straight into your running app, simulating real-world hacker attacks and catching runtime vulnerabilities during active testing, before attackers can exploit them, because if your DAST scans can uncover vulnerabilities, hackers can too. Finding and fixing these issues before deployment means you’re protecting your apps and slamming the door on cyber attackers.
In theory, it sure sounds handy. With DAST, you can:
- Spot Runtime Vulnerabilities Before Release: DAST helps identify security issues in your running application that might be missed during static analysis—especially those triggered by configuration, runtime behavior, or input validation failures.
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Think Like a Hacker: DAST tools mimic actual hacker tactics, showing you how attackers might exploit your app. You basically become your own friendly hacker!
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Easily Integrate: Effective DAST tools let you integrate results with other security methods, giving you a unified view of your app’s security health. With Checkmarx DAST’s unified platform, you can take advantage of the synergies between SAST and DAST under one roof.
- Customize Scans: You can easily configure your DAST scan settings—choose which URLs to include, exclude, or test under different user permissions.
What Can’t DAST Do?
Like we said, DAST is awesome, but it’s not a silver bullet that magically makes your apps unhackable. Here at Checkmarx, we believe that nothing in AppSec exists in a vacuum, and a comprehensive platform approach is needed. For example, here are some of DAST’s blindspots:
- No Code-Level Traceability: DAST won’t point you to the vulnerable line of code. While it can infer severity based on response behavior, it lacks the full context that static or interactive testing can provide.
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Time Intensive: In certain instances, thorough DAST scans can take some serious time, especially if you’re scanning complex applications.
- Some Expertise Required: Understanding and interpreting DAST results often requires deep web application security know-how.
While DAST is traditionally conducted in pre-production environments and serves as one of the last verification steps before release, modern DevSecOps practices are integrating DAST earlier in the SDLC. However, using DAST scans on their own are hardly a complete strategy when shifting left. . Since DAST typically runs late in the SDLC, it’s not aligned with shift-left practices on its own. But when combined with SAST and other early-stage tools in a unified platform, it strengthens coverage across the entire development lifecycle.