This type of malware is very, very disturbing. One can only wonder how many users have been duped into installing ineffective security software, and what happened to their private information and credit card data when they paid for it. The presence of such software, and the overall very high quality of the ruse it presents, is frightening. More than likely, thousands of people have been fooled. In fact, this type of deception has been around for several years now, and it would not still be here if it did not work well.
This should serve as a dire warning to all: be extremely careful what you trust, and question everything that looks even remotely suspicious. For example, no website can run an anti-malware scan on your computer simply by your visiting the site. Any site that purports to do so is almost certainly run by criminal gangs.
No website should ever offer you to download an anti-malware package as soon as you visit the site. Any site that purports to do so is either run by criminal gangs or by an organization whose business practices are so deceptive that you should never consider doing business with it. A reputable site will present you with product information and then leave the downloading decision up to you, not force it upon you. No software that pushes the purchase decision so heavily in your face is likely to be legitimate.
Finally, learn just a little about how your computer looks normally so you can detect changes. The fake Windows Security Center is a very nice touch that could fool almost anyone except who doesn't pay attention to what the real one looks like and is called.
As for your anti-malware software, yes you need it. We all really do, at least on some computers. Advocating that you should stop using anti-malware software is irresponsible. If people were to actually take that advice, we would be overrun with malware in short order. You should definitely have anti-malware software on any computer that may come into contact with untrusted data and software.
However, do not just pick software because it tells you do pick it. Stick to the trusted brand names when it comes to anti-malware. And, if you get a download shoved down your computer when you visit a website, head over to Virus Total and submit it for a scan. If it proves malicious, they will submit it to the anti-malware vendors for you. ®
Jesper M. Johansson is a Software Architect working on security software and is a contributing editor to TechNet Magazine. He holds a Ph.D. in Management Information Systems, has more than 20 years experience in security, and is a Microsoft Most Valuable Professional (MVP) in Enterprise Security. His latest book is the Windows Server 2008 Security Resource Kit.