Im running dual boot windows and ubuntu..windows for gaming, ubuntu for Virtualbox.Now I was wondering say the virus leaks from Vbox to ubuntu (i heard the chances are REALLY low) would it be able to travel over to the other OS (Windows)
Any virus, or malware will easily cross over via any shared files or executables.
The file is already on the hard drive regardless if his PC is infected. However it won't be able to operate in another system.
IE: You can't run the Cats.exe virus on a mac, since .exe is only windows. Therefore the virus is just another junk file that can't do anything.
Edit: By system I don't mean a physical system but an OS
Uh, yes it will. VMWare (or VirtualBox) running Windows, sharing a common directory with another copy of Windows installed as dual boot. Or, Linux side running WINE, also sharing a common directory with a dual booted Windows installation. In either case an infected file or executable can carry that virus/malware across to the other side quite easily. Been there, done that, got a closet full of T-shirts. WINE long ago reached a level of compatibility that viruses are a real threat, and I've seen one or two break out of the sandbox and cause some issues in ~.
For the record, I have seen (though it's been a long, long time) a cross platform virus.