Valve has announced that it is now mandatory for game developers to explicitly declare whether their game(s) use any anti-cheat technology in kernel mode, in a new Steamworks Developer post. Steam Pages for games utilizing kernel-level anti-cheat tools will share this information available for greater transparency - side by side with the already existing DRM warnings, Denuvo for instance.
For the uninitiated, your Operating System has two distinct modes, user mode, and kernel mode - divided based on privileges and permissions. Whatever is happening right now on your screen, that's the user mode. For direct hardware access and interaction, the OS has a kernel baked in, which acts as a supervisor for your system. Software present at the kernel level or ring 0 manages memory, performs context switches, and interacts with the hardware through drivers and whatnot. If any unforeseen error occurs at the user-mode level; fine and dandy. However, if kernel-level software fails - say your GPU's drivers, then your PC may halt and is likely to crash.
Valve has now made it compulsory for game developers to state if their games feature kernel-level anti-cheat utilities. Please note that disclosure is optional if the anti-cheat works in user mode, but this is still a positive change nonetheless. Valve states, "Going forward, when you submit a new game to Steam, if your game installs a client-side, kernel mode anti-cheat, you will need to fill out this new field. We will be going through old games and contacting partners with games that fall into this category." Developers also have to specify if the anti-cheat modifies OS files and if it can be fully uninstalled using the provided script.
Games use kernel mode software more than you'd think; Apex Legends, Fortnite, Paladins, Rainbow Six: Siege, Valorant, H1Z1, and Day-Z to name a few. The argument is that hacking and cheating tools nowadays are built to function at ring 0. Effectively warding them off is only achievable with anti-cheat technology that also operates in kernel mode. But that begs the question, would you allow proprietary software to run on your system's most vulnerable and authorized level just to play a game?
In the end, both sides have valid points but a transparent disclosure looks like a good policy. Users must be informed beforehand if the game they're about to play requires software that runs with ring 0 privileges and that is exactly what Valve is trying to accomplish.
