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GrimAC Anticheat

GrimAC Anticheat

ViaVersion Notice

While we usually recommend that you install ViaVersion on your proxy, GrimAC requires ViaVersion to be installed on the backend servers where GrimAC is installed. ViaVersion must not be installed on the proxy, when using GrimAC. Other Via plugins should also be installed on the backend.

Overview​

This guide will explain the install process and the basic configuration of GrimAC. GrimAC is an open source project, meaning you can review the code on their GitHub.

Besides being a standalone Anticheat, GrimAC is also commonly used along with Vulcan Anticheat for a more comprehensive approach to hacking prevention and punishment.

Usually GrimAC is used to handle the following hacking methods, while Vulcan is usually used to cover combat specific hacks:

  • Movement Hacks: GrimAC has a sophisticated movement mirroring system that allows the plugin to detect movements that shouldn't be possible.
  • Network Auditing: GrimAC is especially good at compensating for latency and other packet tweaking methods due to its ability to predict what a right packet (and order) should look like.

Prerequisites​

Before following this guide, make sure you have:

  • GrimAC has PacketEvents as a dependency. However, GrimAC now includes PacketEvents by default. You might need to add PacketEvents if you try to use older versions.

Installation & Setup:​

You can grab the GrimAC Jar from their Modrinth page. Once you have the plugin's .jar file you can drag and drop it on your server's plugins directory via the File Manager. The plugin will load and generate its config file upon restarting. Keep in mind GrimAC must go on each of your backend servers if you have a proxy based network.

GrimAC is pretty much "plug and play", providing some pretty decent defaults. However, if you notice issues or the protection isn't quite up to spec, keep reading. Likewise if you have a network continue onto the following section to learn about the database options available.

Configuration​

In the GrimAC folder within plugins we'll find 2 main config files which are of interest to us, and a directory:

  1. config.yml: Here we'll find the bulk of the configuration options we care about. Mainly, it includes everything detection related, meaning the triggers that cause GrimAC to act.
  2. database.yml: Where we'll be able to pick and configure which storage system we wish to use for GrimAC.
  3. databases (directory): The databases directory holds config files for each storage type, including both credentials and general database settings.

Database​

First we'll deal with database.yml. This is pretty simple, the development team recommends that anyone who is not running a network stay on the default, SQLite. However, if you are running a network (with multiple backends) or plan to do so eventually, you should use mysql. To start using MariaDB/MySQL, you need to change the first part of database.yml to look like the example below:

database:
  enabled: true
  routing:
    violation: mysql
    session: mysql
    player-identity: mysql
    setting: mysql
    blob: none

Now, you'll need to create a new database following our Database Guide. After creating a database, you'll need to edit the mysql.yml file which we'll find within the databases directory. You'll only need to edit the credentials so they look like the example below, using your own credentials as seen in the guide linked previously:

mysql:
  # Connection target.
  host: "ash-ppg-1020.bloom.host"
  port: 3306
  database: "s114029_GrimAC"
  user: "u114029_arhGJnqVKC"
  password: "jg3NQXbhDPDYXSdYqMB0gAdJ"

Config​

The GrimAC config is pretty straightforward. If you ever have issues with a specific check, you can try to either lower or increase the detection value (depending on if you get false positives or false negatives) to your liking.

If you have issues with too many misses or too many undue kicks, we recommend contacting the GrimAC community over on their Support Discord.

You can review the default config and its comments on their GitHub.

Info​