Savvy shoppers on the hunt for deals may be getting more than they bargain for, thanks to a new online scam.

A fake e-mail that allegedly offers users of Apple's iTunes Store a $50 voucher is doing the rounds, but instead of store credit, the attached zip file contains malware that could infect your PC.

The threat was identified earlier this week by German firm Eleven Security in a post on its blog. It said it could be assumed that the file contained a Trojan or worm. It was subsequently identified as Mal/BredoZp-B, which can allow malicious users access to your computer. It captures passwords and other information and can delete files on a personal computer.

Black Friday, the day after Thanksgiving, may be a US-based event that traditionally marks the start of the Christmas shopping season for retailers, but many websites offer discounts to their international customers too.

Online retailer Amazon has been offering deals this week to kick-start the Christmas shopping period, while Apple is offering discounts today to Irish shoppers on some of its most popular products, including the iPad, the MacBook Air and iPod.

Holiday periods have traditionally been a time of increased activity for spammers. But the popularity of social networks has given malware a new way to trick unsuspecting people.

Earlier this month, security firm Trend Micro reported a Facebook scam that lured users to click on a link offering a free coffee. A second scam last week enticed users to share a link on Facebook and Twitter for a free $100 voucher for the coffee chain.

"As Facebook users continue to fall for social engineering lures such as the one we reported here, the schemes targeting them are sure to continue," Trend Micro anti-spam research engineer Edista de la Cruz wrote in a blog post.