Uber: Lack of rate limiting on get.uber.com leads to enumeration of promotion codes and estimation of a lower bound on the number of Uber drivers

Invite codes are 5 alphanumeric lower case characters. This means there are 36 26 + 10 possible options for each space in the invite code. In total this means there are 36^5 or 60,466,176 possible invite codes. Through enumerating through all possible invite codes, one can find the total number o...