web-vuln-race-conditions

Race condition vulnerabilities occur when concurrent requests cause unexpected state changes in web APIs. Testing for them involves sending simultaneous HTTP bursts to transactional endpoints to detect state inconsistencies like double-spending or rate-limit bypasses.

Stateful HTTP APIs handling transactional operations are vulnerable to concurrent request race conditions. Common targets include coupon redemption, credit spending, order placement, OTP verification, and other flows where simultaneous requests can bypass rate limits or double-spend.

Yes, you need curl and GNU parallel to scan for race condition bugs using this approach. The testing process requires these command-line tools to execute configurable concurrent HTTP request bursts against your target web service endpoints.

To run concurrent HTTP request testing for coupon reuse vulnerabilities, provide your target URL, authentication token, request payload, and desired concurrency level. The testing logic sends simultaneous bursts and summarizes success counts to detect state inconsistencies.

Race condition severity is assessed by classifying the impact of discovered state inconsistencies on financial, authentication, or quota-related flows. The analysis summarizes successful response counts to evaluate the vulnerability's real-world effect.

Yes, you can use concurrent request testing to bypass OTP verification rate limits. By sending simultaneous HTTP requests to the stateful OTP endpoint, the testing process detects race conditions that allow rate-limit bypasses or multiple verifications.