Nitro Anti Cheat - Well

July 27, 2026 · View on GitHub

A host-side moderation mod for Among Us. It protects your lobby, does nothing unless you are the host, and never acts against you.

Features (every one has its own on/off toggle)

Cheat-client detection — kicks known hack clients on sight by fingerprinting the custom RPCs they broadcast: SickoMenu, AmongUsMenu (AUM), and KillNetwork (plus their chat channels).

Name filter — leetspeak-aware. Includes Antipride plus a slur list; catches n1gg3r, n i g g e r, niiigger, etc. Editable blocklist file, no recompile.

Crash / flood protection (individually toggleable):

  • malformed / too-short RPC payloads
  • RPC flooding (tunable threshold)
  • unregistered / unknown RPCs (auto-off in modded lobbies)
  • oversized chat messages

Chat spam — kicks players sending too many messages in a short window.

State checks (individually toggleable):

  • host-only RPCs sent by a non-host
  • cosmetic changes during gameplay
  • gameplay RPCs (murder, vent, vote, meeting, roles...) fired while in the lobby

RPC anti-cheat — illegal vents, teleports in lobby, impostors completing tasks, start-counter spoofing, early meetings, plus role-exploit checks: invalid kills, shapeshifting without being a Shapeshifter, vanishing without being a Phantom, protecting without being a Guardian Angel.

Sabotage / system protection (from Hydra) — validates UpdateSystem: blocks reactor force-fix and force-call crashes, mushroom-mixup spoofing, switch-panel crash payloads, sabotaging as a non-impostor, and sabotage during Hide and Seek. Also door-close in Hide and Seek.

More RPC exploit checks (from Hydra) — fake visual-task animations (PlayAnimation), the never-legitimate Exiled RPC, invalid colour / net-id (SetColor), fake medbay scans (SetScanner), airship platform misuse (UsePlatform), and level spoofing (SetLevel).

Votekick abuse — blocks votekicks from unknown clients, dead players, or outside a meeting.

Banned players (notepad) — an editable list in the panel (also BepInEx/config/NitroAntiCheat_banned.txt). One player name or friend code per line; matches are auto-kicked while you host. Editable even when you're not host.

Auto-mute (meeting) — optional, off by default. "Mute" = the host silently drops the player's chat RPCs for the rest of the meeting (Among Us has no native mute). Two triggers: mute a player once they hold a majority of votes (stops a dying impostor leaking), or mute the player of a colour a majority of living players name in chat.

Exploit protection (self-defense, works even when you're not host) — blocks known mass-grief attacks aimed at you:

  • Ventilation kick/ban exploit — the "everyone gets banned by InnerSloth" attack (forged UpdateSystem(Ventilation) to non-host clients). Blocked.
  • Forced teleport / mass-vent — forged SnapTo aimed at your own player. Blocked.
  • Voting-overload crash — VotingComplete with a huge array length that forces gigabytes of allocation. Blocked.
  • Oversized messages — game-data messages over 1400 bytes dropped. Forgeable vent/movement/teleport checks are discard-only (they block the bad effect but never kick the apparent sender, so a forged mass-vent can't make Nitro kick the victims).

Meeting grace — blocks meetings called before a configurable window (default 10s) after each round starts. Catches modded clients that fire the meeting RPC directly.

Modded lobby toggle — one switch loosens role/gameplay-semantic checks so role mods don't false-positive; name, spam, cheat-client, and crash detection stay active.

Host tools — live map hotswap (Skeld/Mira/Polus/Dleks/Airship/Fungle), lobby spawn/despawn, force crew/impostor win.

GUI — press F8; the window frame cycles through colours (toggle "Rainbow GUI" off if you prefer). Green/orange status line shows host state.

Safety design

  • You are exempt. Your own RPCs are never inspected, flagged, blocked, or punished (player.AmOwner check runs before everything). Using any feature can't kick or ban you.
  • Nothing happens when you're not host. Detection runs and notifies, but no RPC is discarded and nobody is kicked; every control is grayed out and won't toggle.
  • Kick/ban is host-only, gated twice.

Build (you compile it yourself)

IL2CPP BepInEx plugins must be built against your game's interop assemblies.

Prerequisites: .NET 6 SDK; BepInEx 6 (IL2CPP) installed in your Among Us folder (run the game once so interop assemblies generate).

The three build packages live on the BepInEx feed, not nuget.org. The included nuget.config (next to the .csproj) points there. Build from inside the project folder.

  1. Set AmongUs.GameLibs.Steam in NitroAntiCheat.csproj to your game version.
  2. From the project folder: dotnet build -c Release
  3. Output: bin/Release/net6.0/NitroAntiCheat.dll → copy into <Among Us>/BepInEx/plugins/.

Use

  • F8 opens the panel. Host a lobby to activate it.
  • Every check has its own toggle; set punishment (None/Kick/Ban) and thresholds.
  • Name blocklist: <Among Us>/BepInEx/config/NitroAntiCheat_blocklist.txt (one term per line, plain lowercase). Click Reload blocklist file after editing.
  • Settings persist in <Among Us>/BepInEx/config/com.well.nitroanticheat.cfg.

Notes & limits

  • Detection is heuristic; it raises the cost of cheating a lot but can't catch a mod that only does legit-looking things.
  • Map hotswap is the least-tested feature — mid-game ShipStatus swaps can desync in edge cases.
  • Cheat-client fingerprints (Sicko/AUM/KillNetwork) match the RPC IDs those clients used as of this build; a client that changes its IDs would evade that specific check (the behavioural checks still apply).
  • On a game update, if the build errors the likely culprits are the Harmony targets or an RpcCalls/RoleTypes member. Update the game libs.