Internet Archive had its popular Wayback Machine hit with a massive data breach that saw a user authentication database with 31 million unique records stolen. This is a big deal for anyone who has an account on the popular website.

The hacker made a JavaScript message alert claiming they stole user data and that it would show up on Have I Been Pwned (HIBP). The message reads, “Have you ever felt like the Internet Archive runs on sticks and is constantly on the verge of suffering a catastrophic security breach? It just happened. See 31 million of you on HIBP!”

As far as what data the hacker got, Troy Hunt, the creator of HIBP, told BleepingComputer that Internet Archive user email addresses, screen names, password change timestamps, Bcrypt-hashed passwords, and other internal data were included in the large 6.4GB SQL file named “ia_users.sql.”