Adversaries may use Valid Accounts to remotely control machines using Virtual Network Computing(VNC). The adversary may then perform actions as the logged-on user.
VNC is a desktop sharing system that allows users to remotely control another computer's display by relaying mouse and keyboard inputs over the network. VNC does not necessarily use standard user credentials. Instead, a VNC client and server may be configured with sets of credentials that are only for VNC connections.
We will encounter sometimes options where RDP is not available but we do have another form of GUI interface named VNC.
Above we require to have credentials (TIGHTVNC requires Remote Credentials only No username)