Doctored payment machines could be used to lift confidential authorisation codes from Chip and PIN credit and debit cards, security researchers at Cambridge University have discovered.

Shoppers attempting to use fake terminals to make purchases might unwittingly allow scammers to hijack details and make fraudulent purchases using counterfeit cards at another shop. Card identity codes would be sent wirelessly from crooks running fake terminals to accomplices buying goods so that fake cards are accepted as genuine. The PIN is then sent from the fake terminal to the accomplice so fraudulent purchases can be authorised.

Fraudsters inside a store need to insert cards into a tampered machine without detection and inform their accomplices to stand by for the attack (http://www.cl.cam.ac.uk/research/security/projects/banking/relay/) to succeed.

Cambridge University researchers are due to demonstrate the attack on Tuesday's edition of the BBC's consumer rights magazine show Watchdog. The programme features a demo of a cardholder's details being intercepted during a transaction in a book shop and sent to an accomplice via a wireless connection.

UK banking association APACS played down the threat of the attack by saying there's no evidence that the technique has been applied to make fraudulent purchases. "I think we should be more concerned about other types of fraud - there is no evidence that this is about to happen," Apacs' Sandra Quinn told (http://news.bbc.co.uk/2/hi/uk_news/6333929.stm) the BBC.

Cambridge University researcher Steven J Murdoch agrees that it's unlikely criminals are currently using this so-called "Chip & Spin" attack (http://www.lightbluetouchpaper.org/2007/02/06/chip-pin-relay-attacks/), since the next-generation cards remain open to less sophisticated attacks. But, he argues that defences (http://www.cl.cam.ac.uk/research/security/projects/banking/relay/bounding.pdf) against the attack ought to be applied sooner rather than later to prevent relay attacks becoming a significant cause of fraud in the future. ®

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