Pay-by-bonk 'glitch' means cards can go kaching-for-crims

UK researchers reveal attack capable of lifting 999,999.99 currency units from your cards

Researchers from the UK's Newcastle University have outlined how pay-by-bonk cards can be p0wned by a “rogue POS terminal” running on a mobile phone.

To be detailed on Wednesday at the 21st ACM Conference on Computer and Communications Security, the attack is said to rely on a “rogue POS terminal” being set up with a pre-set transfer amount code. When unwitting punters pass the terminal, a wireless transfer of up to 999,999.99 units of any foreign currency becomes possible.

That's bad news because, as the researchers note, in the UK PIN-free pay-by-bonk transactions aren't supposed to exceed £20.

Lead researcher from the University’s Centre for Cybercrime and Computer Security, Martin Emms, suggests the flaw could see crims set up a merchant somewhere in the world and then launch attacks in different locations. Smallish fradulent transactions – perhaps £200 a pop – could be the order of the day, rather than exploits that go for the maximum possible slurp.

Emms says the attack is possible because “All the checks are carried out on the card rather than the terminal so at the point of transaction, [so] there is nothing to raise suspicions.”

“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.”

The good news is that the researchers haven't run tests in the wild. That means banks' fraud detection tools haven't been considered and the researchers admit there's a strong chance they'll nip many transactions generated by this hack in the bud.

But they remain worried that this vuln shows that pay-by-bonk is insecure, and that as it becomes more prevalent so will criminal attempts to exploit any weaknesses in the system. ®

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