A large number of The Pirate Bay users have received an email, allegedly from the site's operators, inviting them to join the private BitTorrent tracker DemUnoid. The Pirate Bay team has distanced itself from the senders, but it remains a mystery how the spammers gained access to the site's user database.

Two months ago a group of Argentinian hackers successfully gained access to The Pirate Bay’s admin panel through a security breach. At the time, the hackers stated that they didn’t want to exploit the vulnerability, and merely wanted to show that the system was vulnerable.

Via the backend of The Pirate Bay website the hackers were able to delete torrents and expose usernames, IP-addresses, emails and MD5-hashed passwords. Once informed about the vulnerability, The Pirate Bay team quickly put a team of people on the issue and promised that it would be fixed as soon as possible.

In the weeks that followed the site continued to operate as usual and nothing was heard from the hackers or the vulnerability again. This week, however, worrying news came in that people affiliated with the private BitTorrent tracker DemUnoid.com (note the ‘U’, not DemOnoid) appear to have gained access to The Pirate Bay user database. Whether the two incidents are related is unclear, but it seems to show that the user database can or could be accessed by outsiders.

In a mass mailing that was sent out a few days ago, many Pirate Bay users received the following message in their email inbox, with the URL redirecting to the registration page of DemUnoid:

Subject: The Piratebay Private Invitation Hello *Username* Have a look at the new site we just launched http://bulkmail.guaranteedmail.net/link.php?*uniqueidherelinkingtoDEMUNOID* The Piratebay

The private tracker DemUnoid.com is obviously not related to The Pirate Bay, and this has been confirmed by a Pirate Bay insider. So who sent it then?

At first this might look as an innocent spam message from people who claim to be affiliated with The Pirate Bay, but a few small details give a clear indication that the senders have access to (parts of) the Pirate Bay user database.

First of all, the emails were sent to the email address that the receivers used to sign up with The Pirate Bay. TorrentFreak spoke to one user who received the message on an email address that he never posted in public and only used to register at The Pirate Bay.

If we combine this with the fact that all the spam messages begin with the accurate Pirate Bay username of the receiver (Hello *Username*) it’s clear that the Pirate Bay user database has been compromised. Without access to the Pirate Bay user database the addresses simply can’t be linked to the correct usernames.

Thus far we haven’t received an official response from the Pirate Bay team regarding this issue, but one of the people close to the site told us that all will be done to find out how this could have happened, and what the source of the leak is.

TorrentFreak also attempted to contact the staff of DemUnoid.com, but we have had no response from their side either. In theory, it could be that a third party used the compromised Pirate Bay user database to send people to DemUnoid, so there is no undisputed evidence that the site’s operators are behind the mass mailing.

It seems that, while some of the people formerly affiliated with The Pirate Bay are on trial, the site itself is facing more and more problems recently. Just two weeks ago, hackers also exploited the site’s ad-server to offload trojans. The ad server issues are fixed now.