business-logic-vulnerabilities

To test race conditions in payment workflows, send concurrent parallel requests targeting check-then-update logic to identify double-spend flaws like redeeming coupons or gift cards multiple times by exploiting idempotency gaps.

Business logic testing systematically maps multi-step workflows to uncover state machine bypasses and authorization failures by attempting step skipping, replaying prior steps, and exploiting cross-step ordering mistakes in API state manipulation.

During black-box pentest, probe price manipulation and coupon abuse by injecting negative quantities or prices, testing rounding precision, stacking promos, and tampering with checkout or refund parameters to violate business rules.

Yes, you can test state machine bypass in multi-step verification flows by checking if servers trust client-supplied state for 2FA completion gating, password resets, and order transitions, allowing unauthorized step-skip access.

The best way to exploit business logic gaps without source code is applying black-box testing playbooks that reason about workflow transitions, concurrent request effects, and authorization state validation across payment and subscription flows.

Workflow step bypass during concurrent API requests occurs when servers fail to properly validate authorization state transitions, allowing parallel requests to exploit race conditions and skip required verification or payment steps.