AshleyMadison site for extramarital affairs hacked

The hackers claimed to have a bevy of personal data on those customers, including their "secret sexual fantasies," according to KrebsOnSecurity, which was first to report the breach.

Avid Life Media — Ashley Madison's parent company — acknowledged on Monday that the site had been hacked but said it had successfully removed all of the stolen information.

Ashley Madison has "been able to secure our sites, and close the unauthorized access points. We are working with law enforcement agencies which are investigating this criminal act," the company said in a statement. "Any and all parties responsible for this act of cyber-terrorism will be held responsible."

Avid Life Media, according to Krebs, believes that the attack was carried out by someone who had worked with its technical systems but was not an employee.

Ashley Madison is an unusual and popular dating website for those seeking extramarital relations.

It gains attention by, among other things, wrapping itself in a social science mantle and publishing data about the frequency and location of cheaters across America, for anyone who happens to be interested, without, of course, mentioning any names.

The hackers also claimed they got "sensitive internal data" for other hookup sites owned by Avid Life Media, such as Cougar Life, which appeals to "single moms and sexy singles looking for a young Stud," and Established Men, which promises to connect "young, beautiful women with successful men," according to Krebs.

Identifying themselves as "The Impact Team," the hackers also claimed that even if customers went the extra mile of paying $20 Ashley Madison to delete their information through a feature called "Full Delete," there were still ways to connect them to the site, allegedly because Ashley Madison retained the name and address tied to a user's credit card.

After initially declining to comment on that accusation, Avid Life Media said in a statement that those claims are false.

The company added that it would offer all users the ability to fully delete their personal information from the site for free. The process involves a "hard-delete" of users' profile information, posted pictures and messages.

If the hackers' claims proved to be true, however, Avid Life Media could draw scrutiny from regulators. The government has gone after technology companies for falsely claiming to delete user information.