Dynamic Application Security Testing (DAST) is a method of testing an application's security by simulating attacks against it while the application is running. DAST evaluates an application's security by analyzing its behavior and interactions with other systems and networks, identifying potential vulnerabilities and providing a report of issues that require remediation. It does not require access to the application's source code, making it a valuable tool for testing third-party applications or applications developed using third-party frameworks. DAST can also help to identify security vulnerabilities that may be missed by other testing methods, such as Static Application Security Testing (SAST). Overall, DAST is a critical component of any comprehensive application security program.