Christmas-themed malware attacks are doing the rounds security firm Websense has warned.
Websense is warning people abou e-mail messages claiming the link to animated cards.
The messages display an animated Christmas scene and appear to come from postcards.org, but instead link to a malicious file called postcard.exe.
Once executed, the malware enables hackers to take control of the compromised PC.
The file is hosted on various servers, including some in top level domains like .com, the Websense alert said.
The guide said users should be wary of enticing offers, e-card greetings, festive attachments and Christmas videos.
All these are used by cybercriminals to steal credit card details directly or install malware to pass on those details.
If there is any doubt about an e-mail it should be deleted and users should avoid opening any attachments, the guide said.
Google statistics show 77% of people plan to do more than half their Christmas shopping online and 86% will research gift ideas using the web.