Man-in-the-Middle Attack Against Chip and PIN
Nice attack against the EMV—Eurocard Mastercard Visa—the “chip and PIN” credit card payment system. The attack allows a criminal to use a stolen card without knowing the PIN.
The flaw is that when you put a card into a terminal, a negotiation takes place about how the cardholder should be authenticated: using a PIN, using a signature or not at all. This particular subprotocol is not authenticated, so you can trick the card into thinking it’s doing a chip-and-signature transaction while the terminal thinks it’s chip-and-PIN. The upshot is that you can buy stuff using a stolen card and a PIN of 0000 (or anything you want). We did so, on camera, using various journalists’ cards. The transactions went through fine and the receipts say “Verified by PIN”.
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So what went wrong? In essence, there is a gaping hole in the specifications which together create the “Chip and PIN” system. These specs consist of the EMV protocol framework, the card scheme individual rules (Visa, MasterCard standards), the national payment association rules (UK Payments Association aka APACS, in the UK), and documents produced by each individual issuer describing their own customisations of the scheme. Each spec defines security criteria, tweaks options and sets rules—but none take responsibility for listing what back-end checks are needed. As a result, hundreds of issuers independently get it wrong, and gain false assurance that all bases are covered from the common specifications. The EMV specification stack is broken, and needs fixing.
Read Ross Anderson’s entire blog post for both details and context. Here’s the paper, the press release, and a FAQ. And one news article.
This is big. There are about a gazillion of these in circulation.
EDITED TO ADD (2/12): BBC video of the attack in action.
moo • February 11, 2010 4:53 PM
Of course its been known for a long time that Chip and Pin does not provide any real security, and is all about shifting the liability onto the customers — but its nice to see these researchers demonstrate it so blatantly.
When criminals can steal your money without even knowing the pin, surely the banks will be forced to acknowledge that its not secure and to accept back the liability that they would much rather foist off on their customers?
It seems rather dangerous to me to keep your money in a bank, these days. (Too bad its almost impossible to get by in modern society without a bank account.)