404 error? Watch out!...

Like many readers of this column, I'm fairly careful about which Web sites I access and what I do there, but occasionally my security software flags up the fact that a nasty bit of trojan code has attempted to invade one of my PCs.

Ever wondered how it happens?

I did, until I discovered that some of the unavailable Web site errors that I encounter on my travels - known as 404 errors in Web parlance - aren't really errors, but traps for the unwary.

It seems that hackers are using common sights such as a 404 errors to encourage users to click-through to a trojan loading routine.

According to Bhaskar Krishna on the McAfee Avert Labs blog, one Web site - http://404dnserror.com - tries to install an ActiveX control and the installation message communicates that page is not available as it's blocked by adware/spyware.

The site asks users to install a security software package called System Doctor to remove the adware and spyware that is preventing the site from opening.

But, yes, you guessed - System Doctor is really part of WinFixer, an adware application that uses deception to encourage people to purchase stuff on t'Internet.

So now you know...