Definition
Dynamic application security testing, or DAST, is a method for finding security vulnerabilities in running web applications by simulating external attacks. It works by sending malicious inputs and analyzing the application's responses to identify weaknesses like injection flaws or cross-site scripting. DAST is crucial for ensuring that applications are resilient against common web-based threats before they are exploited by attackers. For example, a DAST tool might attempt SQL injection attacks against a login form to see if sensitive database information can be accessed. Unlike static application security testing (SAST), which analyzes source code, DAST tests the application in its operational state. This technique is frequently covered in cybersecurity certifications such as CompTIA Security+, CySA+, and CISSP.