Reading a dead game's mind: reconstructing Survarium's login

One of our long-running side projects is bringing back the servers for Survarium, a tactical FPS whose official servers went dark in 2022. There's no source and no protocol documentation, just the game client. The good news is that the client is the spec, if you're willing to read it.

The lucky break

The client binary shipped un-stripped: full symbols and RTTI intact. That's the difference between staring at a wall of anonymous functions and opening a binary where the network classes are still named. Loaded into Ghidra, the login and lobby code reads almost like documentation written by the original developers. Because, in a sense, it is.

From symbols to a handshake

We worked outward from the named networking classes to map the login flow: how the client frames a TCP message, what fields the auth packet carries, and what the server is expected to send back. Each guess gets tested against the real client: if our stub responds wrong, the client disconnects or throws a parse error, and that failure tells us exactly which field we got wrong.

Where it stands

We have Python stubs standing in for the original servers: a TCP service for login and a UDP service for the lobby. The client now authenticates against our server and sits in a stable in-game menu and lobby, with no disconnects and no parse errors, through long unattended runs. The next milestone is matchmaking and the first match-state sync, which is where the genuinely hard part begins.

Why bother

Partly because it's a great game that didn't deserve to vanish. Mostly because this is the most honest kind of engineering there is: the system already works, you just have to understand it well enough to talk to it. It's slow, milestone-gated, and exactly our kind of fun.