Application security testing (AST) is a cybersecurity discipline focused on systematically examining software applications to identify and remediate security vulnerabilities. As a core component of application security, AST integrates various analytical methodologies throughout the software development lifecycle (SDLC) to proactively uncover flaws in application design, source code, third-party libraries, and runtime configurations that could be exploited by attackers.

AST employs diverse techniques including static application security testing (SAST), which analyzes source code without execution; dynamic application security testing (DAST), which tests running applications; and interactive application security testing (IAST), which combines both approaches. By implementing these methods, organizations gain comprehensive visibility into their attack surface, enabling them to fortify data integrity and confidentiality, reduce operational risk, maintain regulatory compliance, and build resilient defenses against evolving cyber threats.