The biggest mistake Ashley Madison customers made: Using their credit cards

Digital extortionists are holding the sexual profiles of potentially 37 million adulterers hostage after a breach of infidelity website AshleyMadison. com. In a ransom message published on the site’s homepage on Monday, the hackers threaten to publish reams of private information unless AshleyMadison.com and its peer site, EstablishedMen.com, are taken offline.

Among that information, the message states, are “all customer records” including “real names and addresses.” In this case, millions of people who were stepping out on their spouses— and hoping and praying that the hackers don’t dump their philandering secrets online—are discovering a serious breakdown in their operational security: They used personal credit cards to pay for the service.

Most people don’t think about it when they swipe a credit card or give the number to an online retailer, but the transaction actually reveals quite a bit about you. First and foremost: your name. In the Ashley Madison hack, those responsible are threatening to expose data that include payment information linked to painfully sensitive details from users’ profiles.

Those profiles contain the findings of an extensive survey given to new Ashley Madison users asking them to outline their reasons for being on the site and their most secret sexual fantasies.

Ashley Madison boasts on its homepage that it is has more than 37.6 million anonymous members. It also touts that it is the leading dating service for “discreet” sexual encounters for married people. Yet while it offers methods for paying fees anonymously, many people apparently didn’t use them.

And despite the site’s assurances about privacy and discretion—including about how charges will show up on customers’ bills—it’s of little use if the data are linked on the backend in a way that hackers or malicious insiders can steal and leverage. Of course, a few basic tricks make it possible to assure at least a modicum of anonymity transacting online.

For those seriously concerned about online privacy—such as human rights activists, whistleblowers, and journalists— such tools as prepaid debit cards, encrypted email and anonymous browsing technologies are the coin of the realm. Many philanderers using Ashley Madison’s services, who presumably took extraordinary steps to hide affairs from their partners, appear to have missed that memo.