Internet Archive’s “The Wayback Machine” has suffered a data breach after a threat actor compromised the website and stole a user authentication database containing 31 million unique records.

News of the breach began circulating Wednesday afternoon after visitors to archive.org began seeing a JavaScript alert created by the hacker, stating that the Internet Archive was breached.

“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!,” reads a JavaScript alert shown on the compromised archive.org site.

The text “HIBP” refers to the Have I Been Pwned data breach notification service created by Troy Hunt, with whom threat actors commonly share stolen data to be added to the service.

Hunt told BleepingComputer that the threat actor shared the Internet Archive’s authentication database three days ago and it is a 6.4GB SQL file named “ia_users.sql.” The database contains authentication information for registered members, including their email addresses, screen names, password change timestamps, Bcrypt-hashed passwords, and other internal data.

Hunt says there are 31 million unique email addresses in the database, with many subscribed to the HIBP data breach notification service. The data will soon be added to HIBP, allowing users to enter their email and confirm if their data was exposed in this breach.

The data was confirmed to be real after Hunt contacted users listed in the databases, including cybersecurity researcher Scott Helme, who permitted BleepingComputer to share his exposed record.

9887370, internetarchive@scotthelme.co.uk,$2a$10$Bho2e2ptPnFRJyJKIn5BiehIDiEwhjfMZFVRM9fRCarKXkemA3PxuScottHelme,2020-06-25,2020-06-25,internetarchive@scotthelme.co.uk,2020-06-25 13:22:52.7608520,N0NN@scotthelmeNNN

Helme confirmed that the bcrypt-hashed password in the data record matched the brcrypt-hashed password stored in his password manager. He also confirmed that the timestamp in the database record matched the date when he last changed the password in his password manager.

Hunt says he contacted the Internet Archive and began a disclosure process, stating that the data would be loaded into the service in 48 hours, but he has not heard back since.

It is not known how the threat actors breached the Internet Archive and if any other data was stolen.

Earlier today, the Internet Archive suffered a DDoS attack, which has now been claimed by the BlackMeta hacktivist group, who says they will be conducting additional attacks.

BleepingComputer contacted the Internet Archive with questions about the attack, but no response was immediately available.