Twitter is recommending that all 330 million users change their passwords after a recent discovery showed that they were exposed to Twitter employees. The bug has been resolved, but every Twitter user is going to see a notice today advising them to roll secrets just in case.
Part of this has to do with how passwords are processed by most log-in systems. Rather than store the password itself, the password is fed through a program (a hashing algorithm) that spits out a completely different string of text. So, for instance, if your password is FancyDenim, the hash might be something like this: $2y$10$7dTxpft0p.aorXz6XxSUnum2p83jPiKWyoa5oajZDFJ.39rFsxgpS (you can try it out here). The latter is what Twitter stores in its database, so that way, Twitter doesn’t actually have your password on file.
“Due to a bug, passwords were written to an internal log before completing the hashing process,” Twitter explained. “We found this error ourselves, removed the passwords, and are implementing plans to prevent this bug from happening again.”
In other words, the passwords were exposed to Twitter employees with access to the log files, and (theoretically) not anyone outside of the company — and Twitter found the problem itself. Still, tech employees aren’t inherently trustworthy. Facebook recently fired multiple employees for snooping on users. You should change your password anyway.