Russian internet portal and email provider Rambler.ru has become the latest victim in a growing list of historical hacks.
Breach notification site LeakedSource.com, which obtained a copy of an internal customer database, said the attack dates back to February 17, 2012.
More than 98.1 million accounts were in the database, including usernames, email addresses, social account data, and passwords, the group said in a blog post. Unlike other major breaches, those passwords were stored in unencrypted plaintext, meaning anyone at the company could easily see passwords.
The last time a breach on this scale was found using plaintext password storage was Russian social networking site VK.com, which saw 171 million accounts taken in the breach.