business-logic-vulnerabilities

SKILL: Business Logic Vulnerabilities — Expert Attack Playbook

AI LOAD INSTRUCTION: Business logic flaws are scanner-invisible and high-reward on bug bounty. This skill covers race conditions, price manipulation, workflow bypass, coupon/referral abuse, negative values, and state machine attacks. These require human reasoning, not automation. For specific exploitation techniques (payment precision/overflow, captcha bypass, password reset flaws, user enumeration), load the companion SCENARIOS.md. For the workflow approach itself (modeling → state machine → attack-surface matrix → human judgement) load METHODOLOGY.md. For the per-module check items load CHECKLIST.md.

Companion files

Extended Scenarios

Also load SCENARIOS.md when you need:

• Payment precision & integer overflow attacks — 32-bit overflow to negative, decimal rounding exploitation, negative shipping fees
• Payment parameter tampering checklist — price, discount, currency, gateway, return_url fields
• Condition race practical patterns — parallel coupon application, gift card double-spend with Burp group send
• Captcha bypass techniques — drop verification request, remove parameter, clear cookies to reset counter, OCR with tesseract
• Arbitrary password reset — predictable tokens (md5(username)), session replacement attack, registration overwrite
• User information enumeration — login error message difference, masked data reconstruction across endpoints, base64 uid cookie manipulation
• Frontend restriction bypass — array parameters for multiple coupons (couponid[0]/couponid[1]), remove disabled/readonly attributes
• Application-layer DoS patterns — regex backtracking, WebSocket abuse