An unredacted version of a database said to be stolen from Adult Friend Finder is being offered for sale for 70 bitcoins, or around US$17,000.
ROR[RG], the nickname of the person who claims to have breached the large online hookup site, wrote on Saturday in an underground forum that "I have had so many people ask me to buy the db today."
Seeking to capitalize on the momentum, ROR[RG] — who claims to live in — also offered to break into any company or website for 750 bitcoins, worth about $170,000.
Fifteen files of data purported to come from Adult Friend Finder were posted to an underground forum in March. The files contained 3.9 million email addresses and in some cases the partner preference, gender, birth date, state, post code, language preference and IP address of users.
In an update posted Friday, the website's owner, FriendFinder Networks, wrote "there is no evidence that any financial information or passwords were compromised.
It's suspected that credit card data may have also been compromised but was removed from data that was released. In the post, ROR[RG] did not indicate if the unredacted version contains payment card information. In older posts, ROR[RG] didn't answer people who had asked if that data was also available.
Some leaked files have a column for "paymenttype." Most are empty, but a few indicate "cc" for credit card. The leak of payment card information would add a new, damaging dimension to the breach.
There are a variety of ways for cybercriminals to monetize data. Since email addresses have been released, it is possible for spammers to begin targeting people by incorporating the Adult Friend Finder email addresses into their mailing lists.
The Adult Friend Finder data is also sensitive since it's easy now to figure out who has subscribed or registered with the site at one time. Troy Hunt, a Sydney-based software architect, has added the Adult Friend Finder data to his Have I Been Pwned website.
Hunt has collected the data from many of the large data breaches over the last few years. Have I Been Pwned lets people check if their usernames or email addresses are in the batches of leaked data.
FriendFinder Networks also wrote in its Friday update that it has disabled the username search function and masked the usernames of affected users.
"We are also in the process of communicating directly to members on how to update their usernames and passwords," the company said.
The Federal Bureau of Investigation has been notified, and FriendFinder Networks said it has hired FireEye's investigative services unit Mandiant to audit its systems.
Sign up for CIO Asia eNewsletters.