A new report by Transunion subsidiary Iovation shows that online retail fraud surged 29% during the Thanksgiving holiday weekend around the world, from year-ago figures, as hackers and other bad actors moved to take advantage of a growing use of mobile and other ecommerce shopping methods.

The report shows that 15% of ecommerce transactions between Thanksgiving and CyberMonday may have been fraudulent and Black Friday saw a spike, with about 25% of the suspected fraudulent transactions taking place on that day. 

Officials at the company said the increase is due in part to the rise in ecommerce shopping, and in particular mobile devices, which is causing a change in how hackers conduct fraud attacks. 

"There is a definite uptick in consumers transacting via mobile devices, which is why fraudsters are increasingly using mobile emulators to masquerade as good customers," Angie White, manager at Iovation told Mobile Payments Today via email.

She explained that emulators are virtualization tools that run atop desktop computers, but mimic the operating systems of a device, including Android and iOS mobile phones. 

"Cybercriminals use emulators to appear more legitimate before perpetrating other attacks such as credential stuffing, account takeover or testing stolen credit card numbers," she said. 

Another method is socially engineering a contact agent to swap a SIM from a legitimate customer's mobile phone to the device of a fraudster, which gives the attacker access to all the victim's mobile apps and accounts stored on that device.