Malware is often also executed in a sandbox, which is how most of the online scanning solutions are analyzing malware. This happens in a matter of minutes, but imagine how long it would take to reinstall a system or restore from the last image when a physical host is involved. One great feature of virtual machines is that they provide snapshots where we can create a snapshot, install malware and infect the whole system, and later revert the snapshot to restore the system to the old state (without malware infection).

There are a lot of options regarding networking, where we can use host-only, internal, NAT or bridged networking that enables virtual machines to have full, partial or none access to the network.

It will be slower than it would be if installed directly on the hardware but depending on what programs you use this may not matter to you.Malware analysis today depends on a great deal of factors, but we’re often using a virtual machine in order to analyze malware: this is because virtual machines are easy to reinstall and configure. There is a downside to virtualisation software however. If you are running Windows make sure it adequate protection whether host or guest OS. Any malware in your Windows host is just as capable of trashing your Ubuntu guest as it is of trashing any other part of Windows. If your host operating system: Windows gets infected however this does not protect the guest OS Ubuntu.

I am not aware of any real world examples of such a threat however. There is a theoretical risk but any malware would need to know that it was running on VMWare which was running on a Windows host. VMware, Virtualbox and similar products are an effective jail for the guest system so if the guest system becomes infected it's unlikely to be able to infect the host. Using Ubuntu through virtualisation software such as Virtualbox or VMware should provide reasonable protection to the host from any malware in the guest system provided you have are not sharing resources such as folders between the two systems.

How to use virtualbox for virus testing