Sophos is warning Apple Mac users to "be on their guard" against websites hosting malicious code designed to infect their systems.
This follows the discovery of a new version of the OS X/RSPlug Trojan horse that is being distributed via a legitimate-looking website offering HDTV software.
"There is much less malware for the Apple Mac than there is for Windows, but that doesn't mean that Apple fans can hide their head in the sand like ostriches", said Graham Cluley, senior technology consultant for Sophos.
"Mac users are no different to Windows users when it comes to falling for social engineering tricks like this - they are just as likely to install and run this program on their computer if they believe it will help them watch high definition TV".
There's more info and advice from Sophos on the company's blog.