Members of Rex Mundi have published personal and financial information from customers of payday lender AmeriCash Advance after the company refused the hacker's demands for a payment of $15,000.

"The batch contained the names and e-mail addresses of the applicants, as well as the last four digits of their Social Security numbers and the amount they requested on loan," writes Help Net Security's Zeljka Zorz.

In a statement provided to CNET News' Elinor Mills, the company said, "On June 12, AmeriCash Advance received a fax, telling us that part of our Web site had been hacked. The letter went on to demand initial payment of $15,000 from us. We immediately notified the appropriate authorities and promptly took steps to ensure that no other data could be accessed. We will not cave in to blackmail, and are cooperating fully with the authorities to protect our customers and bring these criminals to justice."

"Rex Mundi appears to have been on a tear of late as it follows a similar template," writes InfoWorld's Ted Samson. "The group claims to have stolen data over the past couple of months from organizations, including a loan company called Elantis and a temp agency called AGO-Interim. The group's modus operandi evidently includes publicly criticizing its targets' lackluster security and business practices."