'Each generated card field can be used in succession to generate the next field and so on. 'The unlimited guesses, when combined with the variations in the payment data fields make it frighteningly easy for attackers to generate all the card details one field at a time. This means it's quite easy to build up the information and piece it together like a jigsaw. 'Secondly, different websites ask for different variations in the card data fields to validate an online purchase. This allows unlimited guesses on each card data field, using up to the allowed number of attempts - typically 10 or 20 guesses - on each website. 'Firstly, the current online payment system does not detect multiple invalid payment requests from different websites. 'This sort of attack exploits two weaknesses that on their own are not too severe but when used together, present a serious risk to the whole payment system,' explains Mohammed Ali, a PhD student in Newcastle University's School of Computing Science and lead author on the paper.

Investigators believe this guessing attack method is likely to have been used in the recent Tesco cyberattack which the Newcastle team describe as 'frighteningly easy if you have a laptop and an internet connection.'ДЄnd they say the risk is greatest at this time of year when so many of us are purchasing Christmas presents online.

Research published in the academic journal IEEE Security & Privacy, shows how the so-called Distributed Guessing Attack is able to circumvent all the security features put in place to protect online payments from fraud.Д®xposing the flaws in the VISA payment system, the team from Newcastle University, UK, found neither the network nor the banks were able to detect attackers making multiple, invalid attempts to get payment card data.Д«y automatically and systematically generating different variations of the cards security data and firing it at multiple websites, within seconds hackers are able to get a 'hit' and verify all the necessary security data.

Visa credit card hack