Cybercrime forums have been abuzz this week over news that BriansClub — one of the underground’s largest shops for stolen credit and debit cards — has been hacked, and its inventory of 26 million cards shared with security contacts in the banking industry. Now it appears this brazen heist may have been the result of one of BriansClub’s longtime competitors trying to knock out a rival.

Last month, KrebsOnSecurity was contacted by an anonymous source who said he had the full database of 26M cards stolen from BriansClub, a carding site that has long used this author’s name and likeness in its advertising. The stolen database included cards added to the site between mid-2015 and August 2019.

This was a major event in the underground, as experts estimate the total number of stolen cards leaked from BriansClub represent almost 30 percent of the cards on the black market today.

The purloined database revealed BriansClub sold roughly 9.1 million stolen credit cards, earning the site and its resellers a cool $126 million in sales over four years.

In response to questions from KrebsOnSecurity, the administrator of BriansClub acknowledged that the data center serving his site had been hacked earlier in the year (BriansClub claims this happened in February), but insisted that all of the cards stolen by the hacker had been removed from BriansClub store inventories.

However, as I noted in Tuesday’s story, multiple sources confirmed they were able to find plenty of card data included in the leaked database that was still being offered for sale at BriansClub.

Perhaps inevitably, the admin of BriansClub took to the cybercrime forums this week to defend his business and reputation, re-stating his claim that all cards included in the leaked dump had been cleared from store shelves.

Meanwhile, some of BriansClub’s competitors gloated about the break-in. According to the administrator of Verified, one of the longest running Russian language cybercrime forums, the hack of BriansClub was perpetrated by a fairly established ne’er-do-well who uses the nickname “MrGreen” and runs a competing card shop by the same name.

The Verified site admin said MrGreen had been banned from the forum, and added that “sending anything to Krebs is the lowest of all lows” among accomplished and self-respecting cybercriminals. I’ll take that as a compliment.

This would hardly be the first time some cybercriminal has used me to take down one of his rivals. In most cases, I’m less interested in the drama and more keen on validating the data and getting it into the proper hands to do some good.

That said, if the remainder of BriansClub’s competitors want to use me to take down the rest of the carding market, I’m totally fine with that.