This question already has an answer here:
I'm dealing with a hypothetical infrastructure for enabling workers to use RDP for remote access to their work PCs. These would be virtualized Win7 machines within a VMWare vSphere environment. Workers would have to use a VPN client installed on their PCs/notebooks at home to connect to a VPN gateway and traffic is then routed through a firewall to the LAN where the vSphere environment is situated.
What are the most common security threats that have to be considered when doing a security analysis and/or risk analysis?
I just found this question which answers mine as well partly, but I would also like to know more about threats concerning RDP when used to connect virtual machines.