Abusing phone verification to steal money from Instagram, Google and Microsoft

Here's a fun read. A security researcher found a way to abuse phone verification systems to steal money from major corporations Google, Instagram and Microsoft. He was able to trick the verification system into calling premium phone numbers. After he reported the vulnerabilities, he received a total bug bounty of $2500, which might be considered a small amount of money compared to the damage he could have done.

https://www.arneswinnen.net/2016/07/how-i-could-steal-money-from-instagram-google-and-microsoft/