People in Australia have been receiving phone calls from someone claiming to be from Microsoft.
He tells people that their PC is infected with malware, and gives them instructions on how to fix it. What really happens is that his instructions actually installs malware on the PC so that he can log into their computer and steal passwords.
And then to make things even worse, the caller asks for a payment for this service, asking for credit card details.
This person has also been impersonating other IT companies, not just Microsoft. This type of scam has been around for a while in other countries.
If you receive an unsolicited call from a random stranger claiming to help you with a problem you didn’t know you had, challenge them, insist they’re wrong, and basically ignore their advice. If there was a real problem on your PC you should be the one initiating a phone call, not the other way around.
If you feel you’ve been victimised by this, or have information to share, you can call the Australian Competition & Consumer Commission, details here.
Update 4 Oct 2012:
The US FTC has been investigating the problem with cooperation with Australia’s ACMA and several other agencies around the world and has taken some action. They identified 14 overseas companies involved in the scam, and have had the assets frozen for 6 of them. It’s a good attempt to stop the scam, but doesn’t make it go away completely. More info here.