Static Application Security Testing (SAST) is a method of security testing that analyzes source code, bytecode, or binary code for vulnerabilities without executing the program. It is a white-box testing technique which requires access to the internal structures and workings of the application. As a white-box testing method, SAST tools scan the code to identify potential security issues like buffer overflows, SQL injection, command injection and cross-site scripting. These tools use pattern matching, data flow analysis, and control flow analysis to detect vulnerabilities and generate detailed reports with recommendations how to fix. Overall, SAST is a valuable and important tool for enhancing an application's security by identifying vulnerabilities early in the development lifecycle and supporting continuous integration and deployment practices.