Lab 272 — SwiftMart — Race Condition in Promo Code Redemption

hackadvisor

Task: Digital marketplace with wallet system where each user gets a single-use $50 promo code, but premium vault items cost $500+. Solution: TOCTOU race condition on promo code redemption endpoint — fire 200 concurrent requests using threading.Barrier to redeem the same code multiple times before it's marked as used, inflating wallet balance to purchase the vault item containing the flag.