Microsoft Engineer robbed Xbox 10M$

Then Kvashuk found a bug that would change his life, a flaw so stupidly obvious that he couldn’t bring himself to report it to his managers. He noticed that whenever he tested purchases of gift cards, the Microsoft Store dispensed real 5x5 codes. It dawned on him: He could generate virtually unlimited codes, all for free.

Kvashuk started small, generating Xbox cards in increments from $10 to $100. But his haul quickly escalated. By the time federal agents caught up with him almost two years later, he had stolen more than 152,000 Xbox gift cards, worth $10.1 million, and was living off the proceeds in a seven-figure lakefront home with plans to buy a ski chalet, yacht, and seaplane. This past November, a judge sentenced him to nine years in prison.

https://www.bloomberg.com/features/2021-microsoft-xbox-gift-card-fraud/