VirtualBox - Install, Upgrade
The EXE installer of VirtualBox doesn't appear to support silent installation or upgrading. However, it does contain an MSI which can be extracted like this:
For some reason it will prompt for elevated privileged even though it merely extracts an MSI to the current users
Once the MSI is extracted you just need to upload it and add the usual
/qnparameter to make MSI silent.
You are now ready to deploy or upgrade VirtualBox.