Windows Calc.exe Denial of Service Attack
I couldn’t find this interesting bit of behavior documented anywhere on the Internets, so I figured I’d share. Virtual Server is a Microsoft product that is basically just Virtual PC for server operating systems, and allows you to connect to your virtual machines from any workstation on your network. This is all fine and good, and very useful. However, a very interesting event occurs if you happen to have the following circumstances:
- You have one of those “Internet” keyboards with the special buttons to get E-mail, web, etc.
- One of those special buttons is for the calculator.
- You are connected to a Virtual Server VM and you press the aforementioned special calculator button
What happens is that your virtual machine will try to open, oh, about a million instances of calc.exe, and there’s really no way to stop it. The virtual machine spirals out of control, repeatedly spawning new calc.exe processes.
(click for a bigger version)
This is vastly entertaining when someone else is using the VM at the same time. Even better, if you are connected to another machine via remote desktop from inside your virtual machine, the calc.exe denial-of-service bomb will be passed on to the remote server as well.
The only solution I’ve been able to find is to kill the VM from the Virtual Server console. This is the virtual equivalent of pulling the plug out of the wall.
