The Russian-based cybercriminals currently plundering US retailers could be making as much as $680 million (£425 million) a year from their thefts, a security consultancy in the country has estimated.

Group-IB studied a carding market called ‘Swiped’, one of perhaps half a dozen significant sites used to trade stolen cards, discovering 6.78 million cards for sale. Of these, a stunning 5.5 million were uploaded within the last year alone, underlining the extent to which Russian carding forums are enjoying a boom thanks to appalling US retail security.

Although these sites appear to have many thousands of registered criminal users, around two thirds of the stolen cards traded there were purchased by only 1 percent of the user base, generating nearly $4 million in fees for the forum.

On the supply side, one individual using the handle ‘Rescator’ appeared to have supplied more than five million of the stolen cards between December 2013 and February 2014, as it happens all taken during the infamous attack on Target.  Allegedly a member of the ‘Lampeduza’ crime group, the name of the individual behind this identity and his photograph have been circulated in recent months, but this appears to confirm that speculation.

According to Group-IB, he sold 151,000 of the highest quality cards, netting him $1 million in profit. A total of 5.2 million cards on Swiped were of US origin, 233,000 were Malaysian, and 101,000 were from the UK, with smaller numbers from a clutch of European countries and Brazil. The average  card is traded for $20.

The growth in the carding market could be crowding out other types of cybercrime. Online bank fraud carried out on Russia banks appears to be one loser, with its volume down from an estimated $446 million in 2012 and $490 million in 2011 to $288 million by 2013-2014. Cash withdrawal fraud using the same stolen card details is also down from $122 million in 2011 to $59 million today.

Other types of cyber-fraud – fake software, phishing, the sale of exploits – were also either stable and not rising much or somewhat down on past levels.  This is likely to reverse assuming US retailers get a grip on security and the flow of easy card details starts to dry up – criminals will move back to older strategies.

Only good old pharma spam remains as big a business as ever, raking in an astonishing $549 million.

“With recent cybersecurity events such as the leaks at JPMorgan, Home Depot, Target and others, it pays to know which threats matter and where to best allocate security resources,” said Group-IB CEO, Ilya Sachkov.

He agreed that the uptick in arrests of accused Russian cybercriminals appeared to be having some effect, most likely because it was a new pressure they had not faced before.

“We do see that the increase in arrests of Russian accused cybercriminals is having a positive effect on the industry. This is happening because cybercriminals create tools and services that other people can use to commit cybercrimes, and they don't even have to be professionals.

“The more cybercriminals are accused and sentenced, the safer cyberspace is,” said Sachkov. 

The firm released two previous reports on Russian cybercrime but this year it coincides with an sudden in interest on politically and financially-motivated Russian hackers and their connections to the Russian state.

Suddenly more attacks are being blamed on Russians, including that of the recently-publicised Sandworm group against NATO countries, as well as the high-profile ‘Oleg Pliss’ compromise of Apple iCloud accounts earlier this year.