Remote login to all servers must only permit the use of encrypted communications such as ssh. Windows servers must enforce a minimum of 128-bit encryption for Terminal Services and Remote Desktop communication. All servers running SSH must use a minimum of protocol version 2. Use 2-factor VPN to connect through the firewall first.
Servers storing or processing information belonging to more than one classification must meet the requirements associated with the highest classification. If you aren't able to identify whether or not a server may have HRCI, apply the level 4 controls.