Threat modeling (STRIDE + attack trees)

When it applies

Before or during design — a new feature, service, or architecture — to find what can go wrong at the design level, where fixes are cheapest. Pairs offense knowledge with a structured method.

Why it works

Most breaches exploit design gaps, not just code bugs. Systematically walking each component and data flow against a threat taxonomy surfaces missing controls (authz, validation, isolation) that ad-hoc review misses, and produces a prioritized list of controls and tests.