The 6 seconds it takes to hack a Visa card is ‘frighteningly easy’ (updated)

2 Dec 2016

Collection of Visa cards. Image: Valeri Potapova/Shutterstock

New research into the security of Visa credit and debit cards has described the ability to bypass online payment security methods in just six seconds as “frighteningly easy”.

As the world of fintech and online payments reportedly gets more secure by the year as banks adapt to changing trends, the latest news regarding one of the most common methods of payments for online transactions should come as a major worry.

According to new research conducted by Newcastle University in the UK, details of a person’s Visa credit or debit card can be obtained in as little as six seconds, using a technique known as a distributed guessing attack.

The researchers found that by automatically and systematically generating different variations of the cards security data and firing it at multiple websites, within seconds they were able to identify a ‘hit’ and verify all the necessary security data.

When a person makes a purchase online using a card, they are typically asked to provide the card number, expiry date, CVV security code at the back of the card and sometimes their address.

This attack, lead researcher Mohammad Ali said, exposes two huge weaknesses in the verification system.

‘Frighteningly easy for attackers’

The first weakness indicates the lack of communication between various platforms, as current online payment systems do not detect multiple invalid payment requests from different websites.

The second weakness, the team identified, is that different websites tend to ask for different variations of details in a bid to ensure greater security, yet all it does is help a hacker to build up information on a potential target.

“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,” Ali said.

“Each generated card field can be used in succession to generate the next field and so on. If the hits are spread across enough websites, then a positive response to each question can be received within two seconds – just like any online payment.”

MasterCard unaffected

This means that if a hacker has only the first six digits of the card, they will be able to obtain the three essential pieces of information to make an online purchase within as little as six seconds.

Even the CVV number, that only the holder of the card should be able to see, can be cracked in fewer than 1,000 attempts, thanks to the fact that it is so short in length.

“Spread this out over 1,000 websites and one will come back verified within a couple of seconds. And there you have it – all the data you need to hack the account.”

Worryingly for Visa card owners, Ali and his team determined that it is only applicable to these cards, as MasterCard’s centralised network detects multiple incorrect guesses after 10 attempts.

This distributed guessing attack method, the team believes, likely played a part in the recent cyberattack against the British shopping giant, Tesco.

Updated, 2.48pm, 2 December 2016: Visa has now issued a response to the claims made by the Newcastle University researchers.

It stated: “The research does not take into account the multiple layers of fraud prevention that exist within the payments system, each of which must be met in order to make a transaction possible in the real world.”

The company added that it is “committed to keeping fraud at low levels and works closely with card issuers and acquirers to make it very difficult to obtain and use cardholder data illegally.

“We provide issuers with the necessary data to make informed decisions on the risk of transactions. There are also steps that merchants and issuers can take to thwart brute force attempts.”

Collection of Visa cards. Image: Valeri Potapova/Shutterstock

Colm Gorey was a senior journalist with Silicon Republic