A hacking group called The Consortium has claimed responsibility for the theft of personal data of more than 72,000 users of porn website Digital Playground.
The stolen information includes subscribers' user names, email addresses and passwords. The hackers also stole credit card details - which were in plaintext - of 40,000 cards, including the numbers, expiry dates and security codes (CCVS).
Digital Playground is run by European company Manwin, which is headquartered in Luxembourg.
According to a manifesto posted online, The Consortium described Digital Playground's security as "a joke" and said that the site's lack of security had made it "too enticing to resist".
"This company has security that, if we didn't know it was a real business, we would have thought to be a joke - a joke that we found much more amusing than they will."
As well as describing the personal data it had stolen, the hackers continued: "We also went on and rooted four of their servers, as well as gaining access to their mail boxes. Using credentials from emails we tapped into their conference call. "Is anyone besides David on the line?" - We were. Did we win? Sure looks that way."
The hacking group has also posted links to thousands of the stolen customer emails and passwords from its Twitter account @Th3Consortium.
A spokesperson for Manwin said: "Manwin officially took over Digital Playground and related assets on 1 March 2012, and according to allegations, a potential security breach may have occurred prior to that date.
"Due to the alleged breach, Manwin elected to temporarily shut down DigitalPlayground.com, and related websites, on 5 March 2012. The site was operational again for existing members on 11 March 2012. Security parameters have been verified and the entire system was upgraded during this time period.
The spokesperson added: "Members will not be billed for the period the site was inactive."