VMs + Viruses on a network

[Andinel]

I've been considering installing Windows XP on my Mac so I can run some apps that I wouldn't be able to otherwise, but I'm concerned about viruses. If my VM gets a virus from a website or email, is there any chance that it could affect my underlying Mac OS or the network that I am on, or is it limited to affecting the VM only?

[admin]

If you have Shared Folders or a network share set up on the Mac, a virus in the guest could affect the host. If your guest has network access, a virus could also affect the network. If you want to be safe, keep the guest isolated from the network and make sure shared folders are not enabled.

If you want slightly more functionality, host-only allows the guest to talk to the host, and NAT allows it to talk to the host and the internet relatively safely. Shared folders should be limited

to what you need to share (create a folder just for this!) and can be read-only if appropriate.

[Andinel]

Considering that my entire network at home is on Mac OS X (10.3 or 10.4), is there still a significant risk? Also, I have my firewall enabled and no sharing settings set.

[admin]

I'm not sure that a host firewall protects the guest, especially if the guest is using Bridged mode (you can of course run a firewall in the guest). The network concern would also apply to the internet at large - an infected guest could be pumping out spam or be part of a botnet, as well as just causing slowdown because of heavy traffic. Your other computers at home wouldn't have to worry about being infected, but they could still be impacted.