The hacker also claimed to have accessed the site's entire user database, writing, "Complete Database is in GB's, well we aren't leaking it. We may Keep all parts in our computer. This website have more then 300,000k members, we won't publish it because user_database is in GB's as we said."
Cyber War News reports that the hacker claims to have leveraged a "very easy to find SQL injection vulnerability" to breach the site.
No reason was given for the attack.