Brian Krebs of the Washington Post dropped me a line this morning on a new article he posted. Heartland Payment Systems, a credit card processor, announced today, January 20th, that up to 100 Million credit cards may have been disclosed in what is likely the largest data breach in history. From Brian’s article:

Baldwin said 40 percent of transactions the company processes are from small to mid-sized restaurants across the country. He declined to name any well-known establishments or retail clients that may have been affected by the breach. Heartland called U.S. Secret Service and hired two breach forensics teams to investigate. But Baldwin said it wasn’t until last week that investigators uncovered the source of the breach: A piece of malicious software planted on the company’s payment processing network that recorded payment card data as it was being sent for processing to Heartland by thousands of the company’s retail clients.

“The transactional data crossing our platform, in terms of magnitude… is about 100 million transactions a month,” Baldwin said. “At this point, though, we don’t know the magnitude of what was grabbed.”

I want you to roll that number around on your tongue a little bit. 100 Million transactions per month. I suppose I’d try to hide behind one of the most historic events in the last 50 years if I were in their shoes.

“Due to legal reviews, discussions with some of the players involved, we couldn’t get it together and signed off on until today,” Baldwin said. “We considered holding back another day, but felt in the interests of transparency we wanted to get this information out to cardholders as soon as possible, recognizing of course that this is not an ideal day from the perspective of visibility.”

In a short IM conversation Brian mentioned he called the Secret Service today for a comment, and was informed they were a little busy.

We’ll talk more once we know more details, but this is becoming a more common vector for attack, and by our estimates is the most common vector of massive breaches. TJX, Hannaford, and Cardsystems, three of the largest previous breaches, all involved installing malicious software on internal networks to sniff cardholder data and export it.

This was also another case that was discovered by initially detecting fraud in the system that was traced back to the origin, rather than through their own internal security controls.