The worst spyware of 2008 (in my experience) is certainly Windows XP Antivirus 2008/2009 or one of its many variations. This malware invades a computer in one of many ways, usually bundled with a video codec, or freeware or shareware, or sometimes when you accidentally go to (drive by) a bad website.
Infected computers display warnings and scans that look like Window alerts. They lead you–the besieged users–to buy the rogue product for $40. If you buy the rogue software then the fraudsters now have access to your credit card. (Call your credit card company immediately if this is the case.) And the purchase of the rogue anti-spyware does nothing to relieve the infection, in fact it takes over your computer to make it part of its botnet. This is the part I don’t understand. From my experience the infection makes the computer so totally crippled it can’t function, and for this reason I question how well it would serve even a botnet. But that according to this article is the intention.
And here’s another article about it.
I find Windows XP Antivirus 2008/2009 extremely difficult to remove. Sometimes it comes back even after a Windows Repair from the cd.
Here’s a post that tells how to remove it.
The spyware that seems to have affected the most readers of this blog, is the Hallmark Card virus. So it is the 2nd Worst Spyware of 2008. Here’s how to remove it.
And here’s a great slideshow by Channel Web showing the top ten malware in the news.