What is the difference between DAST and IAST?

DAST and IAST are both methods for detecting application vulnerabilities, but they differ in approach and depth.

DAST (Dynamic Application Security Testing) is an external "black-box" testing method that scans a running application from the outside, simulating real-world attacks like cross-site scripting (XSS) or SQL injection. It tests for vulnerabilities in the live environment without needing access to the application's code, focusing on how it behaves under attack.

IAST (Interactive Application Security Testing), in contrast, is a real-time monitoring system that combines elements of both static and dynamic testing. It operates within the application, monitoring its behavior as it executes. IAST's real-time aspect provides deeper insight by accessing both the internal code and the runtime environment, which allows it to detect more complex vulnerabilities and pinpoint their location within the code.

In summary, DAST tests from the outside, while IAST provides real-time, internal monitoring for deeper vulnerability detection.