Suppose I have two users accounts on a Windows XP Professional machine: user X and Y. Suppose also that both of these accounts are members of the Restricted Users group (instead of being members of the Administrators/Power Users groups).
Suppose user X is interactively logged in and he runs process FOO under his credentials. Assume also that he runs process BAR under Y's credentials (with, for example, the command: runas /user:computername\Y BAR.exe).
Here's the question: can process FOO (started by user X and running as X) communicate with process BAR (started by X but running as user Y) with any sort of inter-process communication? Can BAR communicate with FOO?
If yes, under what circumstances and how? I would assume that because user X has no read permissions over Y's directory (and vice versa), that X's processes would not be able to communicate with Y's processes, but I'm suspicious that it may be otherwise.