I appreciate the answers I've gotten so far, but I might not have worded the question clearly enough.
Is the Windows 7 side of the machine running in XP Mode exposed to any dangers it would not be if it were not running a VM in XP Mode? And are Windows 7+ machines on the network exposed to additional vulnerabilities if a machine boots up an XP VM anywhere on the network?
I realize there is no way to predict specific vulnerabilities that might arise after April 8, 2014. I appreciate the explanations that I've gotten on that, as they're well-written and straightforward. I can use the language there to impress upon our stakeholders why getting everything off of XP ASAP needs to be high on our list of priorities.
What I'm especially curious about, though, is if we can't get off of XP by the end of support, what's the risk to the machines in our environment that aren't on XP? If a virus, worm, or other compromising piece of software gets into the XP VM, is the Windows 7 side infected, too? Or can I wipe out the XP VM and wipe the sweat off of my brow?
Or is that the point? Without being able to foresee what vulnerabilities will arise, we can't really know what the impact might be outside of the XP VM itself.
Our firm is working on migrating everyone from Windows XP to Windows 7, but we have some software that still requires XP. What dangers, if any, will we face in running Windows Virtual Machines in XP Mode after April 8th, 2014?
I know the XP VM would be vulnerable to basically anything that a physical XP machine would be. So I guess what I'm really asking is, what vulnerabilities will my Windows 7 machine be open to when I open a VM in XP mode on April 8th, 2014? Is the Virtual PC an effective sandbox? Or should we try to keep machines running in XP mode off the network if possible?