I have a windows 7 64-bit host (all outbound connections generally blocked) and run virtualbox (5.0.1) with an opensuse 13.2 guest and need to create a firewall rule on the host to allow access from the linux guest to the internet.
Either NAT or Bridged Connection would be fine, as long as all outbound connections on the host system can remain blocked.
Everything I tried so far (trying NAT, Bridged Connection or allowing virtualbox.exe, vboxsvc.exe, vboxnetnat.exe, vboxnetdhcp.exe, etc.) did not work. I only got an internet connection in the guest when I generally allowed outbound connections.