It is possible to remove networking modes from Oracle VM VirtualBox GUI. To do this, use the following command:

VBoxManage setextradata global GUI/RestrictedNetworkAttachmentTypes property[,property...]

property is one of the following:

NAT

Remove the NAT option from the GUI.

NATNetwork

Remove the NAT network option from the GUI.

BridgedAdapter

Remove the Bridged networking option from the GUI.

InternalNetwork

Remove the Internal networking option from the GUI.

HostOnlyAdapter

Remove the Host Only networking option from the GUI.

GenericDriver

Remove the Generic networking option from the GUI.

This is a global setting. You can specify any combination of properties. To restore the default behavior, use the following command:

VBoxManage setextradata global GUI/RestrictedNetworkAttachmentTypes