Online poker site, SealsWithClubs.com was hacked and Affinity Gaming officials claim that the compromise occurred between March 14th and October 16th of this year.
Clients began to see fraudulent transactions and the company suggested that all customers verify credit card activity.
In October, the company was notified that fraud may originate from an Affinity casino in Iowa which triggered an investigation revealing malware.
Although it remains unclear how many customer card numbers were compromised, Jim Prendergast, company attorney, believes the number to be less than 300,000.
Details and source of the hacking are still under investigation.