Anti-cheat

Online games use anti-cheat to keep matches fair. The software looks for programs that give one player an unfair advantage, and the game’s operator acts on what it finds, usually with a ban.

Valve’s own system, VAC (Valve Anti-Cheat), is a well-documented example. Valve describes it as an automated system that detects cheats installed on a player’s computer by their signatures. Any third-party change to a game meant to give an advantage counts as a cheat, including changes to the game’s own executable files and libraries. If a player connects to a VAC-secured server with detectable cheats installed, they are banned from that game’s VAC-secured servers. Valve says hardware configurations and updated drivers, such as graphics drivers, do not trigger bans, and that players are not banned on the strength of reports alone.

VAC bans are permanent and cannot be removed by Steam Support, although Valve says a ban found to be wrong is lifted automatically. A banned player can still play the game on servers that are not VAC-secured, where the game has them. Valve also warns that Family Sharing can be revoked, and the account banned, if someone uses a shared library to cheat.

Anti-cheat has knock-on effects beyond cheating. A game in which your account has a VAC ban cannot be refunded on Steam; see our guide to Steam refunds. And on Steam Deck, a game’s anti-cheat must work through Proton for the game to be rated Verified, as our explainer on Steam Deck Verified sets out.