Valve's anti-cheat team have responded to a Reddit post on the CS:GO subreddit, talking about how they won't automatically detect cheaters, because it can lead to an "arms race" with the people that make these cheats.
The post came in response to a post asking "why are spinbots not auto-detected or at least kicked for improper play." Spinbots are a particularly obvious type of hack which spins the player around incredibly fast that is used in conjunction with an aim-bot — which does exactly what you might think — to allow the aim-bot to acquire targets behind the user.
It's particularly obvious in play, and as such many players have been asking Valve why they can't tackle hackers directly, instead of their current method of a system of using player reports to tackle cheaters.
Valve's response is useful for any developer of an online game, and for those interested in the constant fight to stop hacks and those that create them.
"So some bad news: any hard-coded detection of spin-botting leads to an arms race with cheat developers – if they can find the edges of the heuristic you’re using to detect the cheat, the problem comes back. Instead, you’d want to take a machine-learning approach, training (and continuously retraining) a classifier that can detect the differences between cheaters and normal/highly-skilled players.
The process of parsing, training, and classifying player data places serious demands on hardware, which means you want a machine other than the server doing the work. And because you don’t know ahead of time who might be using this kind of cheat, you’d have to monitor matches as they take place, from all ten players’ perspectives.
There are over a million CS:GO matches played every day, so to avoid falling behind you’d need a system capable of parsing and processing every demo of every match from every player’s perspective, which currently means you’d need a datacenter capable of powering thousands of cpu cores.
The good news is that we’ve started this work. An early version of the system has already been deployed and is submitting cases to Overwatch. Since the results have been promising, we’re going to continue this work and expand the system over time."
For clarity, it seems this system is automatically reporting cheats to Overwatch — Valve's system of flagging footage of cheaters and asking other players to watch it to verify whether or not a player is hacking — instead of immediately bringing down the banhammer. It's interesting to see this semi-automated approach take hold.