Last updated: May 1, 2026
HARD
🔐 PRO
⏱ 120 min
Module 7 of 8
What you’ll learn
- Why scanners cannot find business-logic flaws — and you can
- Race conditions in financial operations — the technique that drains treasuries
- Workflow manipulation — skipping steps, manipulating state transitions
- Price, quantity, and currency manipulation patterns
- Coupon, referral, and promotion abuse
- Time-of-check vs time-of-use (TOCTOU) race conditions
Prerequisites: Modules 1–6. Familiarity with HTTP-level request manipulation in Burp Suite.
Business logic flaws are where the commercially-important findings live. Unlike SQL injection or XSS, they can’t be detected by scanners or generic rules — they require understanding of how the application is supposed to work and identifying where that logic breaks under hostile input.
The findings in this category tend to produce the largest direct financial impact. A race condition in a refund endpoint that lets an attacker withdraw the same credit twice. A workflow bypass that lets a user skip KYC. A price-manipulation vulnerability that accepts a negative quantity and pays the attacker. These bugs have cost real Indian fintechs real crores. Testing for them is the difference between a credible pentest and a scanner report.
The mental model
Business logic vulnerabilities are mismatches between the application’s intended flow and what its code actually enforces. The attacker asks: “What does this feature assume the user will do? What happens if they don’t?”
Examples:
- The password-reset flow assumes the user will click the link once. What if they click it simultaneously from two devices?
- The checkout assumes positive quantities. What if quantity is negative?
- The coupon check assumes one coupon per order. What if two are applied in parallel requests?
- The KYC workflow assumes step 1 completes before step 2. What if the attacker calls step 3 directly?
Custom team training + practitioner advisory
Beyond the free academy — we run private workshops, vCISO advisory, and red-team exercises tailored to your stack. For Indian SMBs scaling past their first hire.