New Trojan Mimics Windows Activation Interface
What they are calling Trojan.Kardphisher doesn’t do most of the technical things that Trojan horses usually do; it’s a pure social engineering attack, aimed at stealing credit card information. In a sense, it’s a standalone phishing program.
Once you reboot your PC after running the program, the program asks you to activate your copy of Windows and, while it assures you that you will not be charged, it asks for credit card information. If you don’t enter the credit card information it shuts down the PC. The Trojan also disables Task Manager, making it more difficult to shut down..
Running on the first reboot is clever. It inherently makes the process look more like it’s coming from Windows itself, and it removes the temporal connection to running the Trojan horse. The program even runs on versions of Windows prior to XP, which did not require activation.
More info here.