According to the official statement, a hacker detected a breach in the service’s protection system and copied database, containing details on 5.6 million users.

The exposed information included:
•    email addresses
•    password hashes
•    users’ IDs
•    IP-addresses
•    authentications tokens for connected devices
•    some other internal Social Blade data 

The company representatives noticed that the intruder didn’t manage to obtain banking cards details and that all passwords were hashed with the help of a reliable BCrypt algorithm. Nevertheless, users were advised to change passwords as a safety precaution.