The company told users via its website that it was the target of an international hacking attack on Dec. 11. The malicious users were able to exploit a flaw in the company's software and access data.
The hackers then threatened to expose the user data on the internet if they are not paid extortion funds, White Wolf said.
"We have no intention of paying this money, and (we) are in contact with the FBI in an attempt to bring these criminals to justice," the company said. "We are choosing to make this public so that our users and fans can take any precautions needed to protect themselves. We are recommending that if you have used your White Wolf password as the password for any other services you use on the internet, that you change them immediately."
The company said it had notified users of the breach by email. All passwords for the site were reset, the company said.
Shlomo Kramer, founder and chief executive officer of Imperva, said Tuesday that the White Wolf site appears to have been hacked from the outside. He reccomended additional data protection to prevent future attacks of this nature.
"The only thing that stands between any user and the data is just an application," he said.