VNC (Virtual Network Computing)
VNC is a cross-platform protocol for remotely viewing and controlling another computer's graphical desktop, built on the RFB (Remote Framebuffer) protocol (RFC 6143) and typically reachable on port 5900. Like RDP, it sends the full screen image and keyboard/mouse input over the network, letting a user operate a remote machine as if sitting in front of it, with implementations available across Windows, macOS, Linux and embedded systems. VNC's original "classic" authentication scheme has a legacy weakness RFC 6143 itself documents: the password is truncated to 8 characters and used as a DES key, which the RFC calls "known to be cryptographically weak." Modern VNC servers can run over TLS or inside an SSH tunnel instead, but a server left on classic authentication and exposed directly to the internet is a well-documented ransomware entry point, the same risk category as an exposed RDP port.
By AdminKit team, Netbase JSC · Updated