VNC is a well-known protocol for remote desktop sharing. This blog post is the story of a web project that led to the creation of a

A Vanity VNC server (or Joke over RFB)

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2024-11-26 12:00:05

VNC is a well-known protocol for remote desktop sharing. This blog post is the story of a web project that led to the creation of a "vainity" VNC.

As a matter of fact, there's a project called VNC Resolver that scans all publicly available VNC servers on the Internet (IPv4). One evening, I stumbled upon one of their Mastodon posts publishing a Nyan Cat in full screen, likely a victim of the Trojan horse MEMZ, which replaces an computer's MBR sector with a program displaying an animated Nyan-cat in full screen. I then had the idea to create a small VNC server that would display a joke.

The goal isn't to increase the attack surface of my personal server (or at least, not significantly), nor consume too many resources. I then became interested into the VNC protocol with the aim of displaying a fixed image from a Rust-written VNC server.

VNC is based on the RFB (Remote FrameBuffer) protocol, which is extremely simple and defined in the RFC6143. This simplicity also makes it powerful. It's relatively efficient because it supports partial updates of the "desktop".