SMS URL verification link does not expire on phone number change and lacks rate limiting

Summary

When verifying your phone number attached to your Uber account, it was possible to re-use an old verification URL to validate a new cell phone number. In addition to this, there was no rate limiting on the SMS verification which allowed for it to be easily brute-forced. The internal team resolved this by removing the ability to perform SMS URL verification in favor of a standard 4-digit verification.

Thanks, @hanuman1!