Contactless credit cards are a hit in the UK. But a British research team has revealed a serious security flaw that allows anyone to charge up to $999,999.99 in foreign currency to a nearby card, even while it's still in a wallet or purse.


Contactless cards let you buy things without a pin, up to a certain limit (£20 in the UK), thanks to radio waves emitted from the card and picked up by a nearby terminal. But according to a team from Newcastle University, there's a serious security flaw in at least one major company's contactless system.

At the ACM Conference on Computer and Communications Security, which is going on this week in Arizona, the team explained how it's easy to set up a point-of-sale terminal using a phone, then create a transaction of up to $999,999.99. Crucially, the payment amount must be requested in foreign currency, otherwise the £20 limit will kick in. Here's a video of the lead author, Martin Emms, demonstrating the hack for the BBC.


"By pre-setting the amount you want to transfer, you can bump your mobile against someone's pocket or swipe your phone over a wallet left on a table and approve a transaction. In our tests, it took less than a second for the transaction to be approved,"said lEmms in a release about the study. "All a criminal would need to do is set up somewhere like an airport or the London underground where the use of different currencies would appear legitimate."

Even if you use a contactless card, though, it's unlikely you'll see any million-dollar transactions popping up on your account any time soon. Emms says it's far more likely that criminals will use the flaw to set up hundreds or thousands of fraudulent transactions in smaller amounts to evade notice. A good reminder to keep an eye on your account, no matter how small the charge. [Newcastle University; BBC]

[Update] Visa Europe has commented on the research, saying there's no cause for concern:

We have reviewed Newcastle's findings as part of our continued focus on security and beating payments fraud. The research does not take into account the multiple safeguards put into place throughout the Visa system, each of which must be met in order to make a transaction possible in the real world. For these reasons we do not believe the findings to be a cause for concern, as it would be very difficult to complete a fraudulent payment of this kind outside a laboratory environment.

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