Security experts say Black Friday shoppers in search of pre-Christmas bargains could face greater risk from cyber thieves both online and in bricks-and-mortar shops.
Bargain hunters are expected to see an increase in phishing scams, with emails designed to look like genuine messages from familiar companies who either ask for payment details or who encourage the reader to download an attachment containing malware.
Experts warn shoppers to be wary of emails containing links to bargain offers on Black Friday.
Merchants on Black Friday and Cyber Monday, the annual shopping days following the U.S. Thanksgiving holiday, are expected to see record sales, along with a huge increase on cyber criminal activities, which could carry on until Christmas and into new year sales.
Increasingly sophisticated cyber thieves could also be targeting shoppers in store, as well as online.
U.K. security company iSight reports that one gang has updated its software to target the tills in shops in order to steal payment details.
Back in the States, the 50 biggest retailers are reportedly searching through their internal computer networks to see if they have been affected by the sophisticated Modpos malware which can grab payment data while it is briefly unencrypted in the memory of computer-based shop tills.
There have also been reports of criminals making fake copies of popular shopping apps in order to gather customer payment details.
Tech Insider