Advanced web assessments must account for distributed architectures, APIs, single-page applications, identity providers, browser security boundaries, and backend microservices. Vulnerability discovery is strongest when mapped to state transitions, authorization flows, and trust assumptions rather than isolated payload tests.

A rigorous approach combines request/response modeling, identity transitions, privilege boundary checks, and differential behavior analysis across roles, devices, and content types. To reason about authorization, compare accessible resources as $R_u$ and $R_a$ for users $u$ and roles $a$; a flaw exists if unauthorized access is possible when $R_u \nsubseteq R_a$ is expected to hold.

Modern front ends often expose state machines, API routes, and business logic that should not be trusted. Scripted workflows, token storage, and cross-origin interactions deserve scrutiny because the browser is an attacker-controlled execution environment.