Hackers access Playboy.com's credit card data

NEW YORK (CNN) -- Computer hackers broke into the Playboy Enterprises' Web site -- playboy.com -- gaining access to the credit card numbers of several customers, a company spokeswoman said Tuesday.

The company's technology team discovered the breach last weekend before the hackers sent threatening e-mails to the company's customers, said Playboy spokeswoman Laura Sigman. Consumers began alerting Playboy about the violation Sunday evening.

It was not clear how many customers' credit card numbers had been accessed or if the hackers had used the information, Sigman said. The hacker group, operating under the name "ingreslock 1524," identified the customer's name, credit card number, and the card's expiration date in an e-mail sent to each of the victims.

EXTRA INFORMATION Timeline: A 40-year history of hacking

In the e-mail message -- obtained by CNNfn -- the group said it "did have some very big plans" to use the information so that it would result in "over 10 million dollars worth of fraud claims" made to credit card and insurance companies.

But the group appeared to be alerting the victims to the fraud in advance of any theft, and later implied that the hacking was just a "test" of the computer system's security. The group said it plans to conduct another "test" Playboy's Web site, but did not say when.

Playboy sent letters to its customers Tuesday, encouraging even those who didn't receive the hackers' message to contact their credit card issuers to check for unauthorized charges.

Playboy said the FBI is investigating the incident, and the company has hired the investigative agency, Kroll Associates. Playboy, which has firewalls in place, is conducting an internal check of its logs and servers.

-- From CNN Financial News Correspondent Fred Katayama.