Vulnerability could impact Twitter financially hard because it could be exploited easily by writing a simple python code or using a simple for loop on 6 numbers. Egyptian Security Researcher Ahmed Mohamed Hassan Aboul-Ela has discovered a critical vulnerability in Twitter’s advertising service that allowed him deleting credit cards from any Twitter account. Using it, a bad actor could delete all credit card from all twitter accounts, resulting in “halting all the twitter ads campaigns and incur big financial loss for Twitter,” according to him. Twitter also started paying individuals for any flaws they uncover on its service with a fee of $140 or more offered per flaw.
Source: https://thehackernews.com/2014/09/twitter-vulnerability-allows-hacker-to_16.html