Valve Anti-Cheat (VAC)

Valve publishes only a general description of VAC's methods. It declines to say which cheat produced any given ban, on the grounds that "releasing this information would only benefit cheat developers". What follows is limited to Valve's own public statements.

Signature matching. Valve states that "The VAC system reliably detects cheats using their cheat signatures." The trigger condition is connecting to a protected server while cheat software is present: Valve writes that "VAC bans are applied when an account, or an account using the phone number tied to other accounts, connects to a VAC-secured server while running cheat software."

File checks. Valve's ban article says "Valve Anti-Cheat regularly checks the game files of all users connected to Valve's servers to ensure third party software is not being used which gives players an advantage."

What counts as a cheat. "Any third-party modifications to a game designed to give one player an advantage over another is classified as a cheat or hack and will trigger a VAC ban," including "modifications to a game's core executable files and dynamic link libraries."

What does not trigger it. Valve lists "System hardware configurations." and "Updated system drivers, such as video card drivers." as things that will not cause a VAC ban.

Player reports. Valve says users "are not VAC banned based on reports alone" and that other factors are taken into account. New cheats can be emailed to Valve, and "All emails are read and reviewed by the VAC development team."

For Counter-Strike 2, Valve also operates an invitation-only review site that identifies itself as "the Counter-Strike 2 VacNet labeling portal".

Per game, recorded on the Steam account. One ban blocks play on VAC-secured servers for the affected title; legacy groupings mean a ban in any one Source title covers all of them, and likewise across the GoldSource list. Bans are also applied to every account sharing the same phone number at the time of the infraction (a feature enabled at the developer's discretion), and can reach the library owner through Family Sharing. Single-player, LAN and non VAC-secured servers remain playable.

Scope. A VAC ban is recorded against the Steam account. Valve states that "VAC bans prevent you from playing on secured servers across all of Steam", while also confirming that banned accounts "can still play single-player games, local LAN games, and multiplayer on non VAC-secured game servers." Two legacy groupings widen the reach: cheating in one Source title results in a ban across the listed Source games, and the same applies across the GoldSource list. Bans are further "applied to all accounts sharing a phone number at the time of the infraction", a feature Valve says is used at the developer's discretion, and Family Sharing can extend a ban to the library owner.

Appeals. There is no appeal route. Valve states "VAC bans cannot be appealed" and that they are "permanent, non-negotiable, and cannot be removed by Steam Support." Bans issued incorrectly are removed automatically after investigation, but Steam Support will not remove one manually, and Valve will not disclose which cheat was detected. Game bans are handled differently: for those, Valve directs players to contact the game developer.