MAST stands for Mobile Application Security Testing. It is the set of methods used to check mobile apps for security weaknesses before they are released or while they are in use. MAST commonly combines static analysis, which examines code or binaries without running the app, and dynamic analysis, which observes the app at runtime.
MAST matters because mobile apps handle credentials, payments, messages, and sensitive business data. Weaknesses in storage, cryptography, authentication, network traffic, or platform interaction can lead to data theft, account takeover, or app tampering. In real defense programs, MAST is often mapped to standards such as OWASP MASVS and integrated into CI/CD so problems are found early and repeated on every build. In attacks, adversaries may reverse-engineer apps, inspect traffic, or abuse weak APIs, so MAST also needs to cover backend dependencies, not just the client.