Kinetic Anti-Cheat is a very simple Anti-Cheat mod to stop people with unwanted mods joining a server.
How does it work?
Kinetic Anti-Cheat scans a player's mods folder and checks it against a whitelist that can be modified by you. If it finds a mod that is not on the whitelist, it will kick them from the server. After kicking the player, the anti-cheat will then print a log with the mods the player tried to join with and their name.
All logs will be saved in the illegal client folder. You can then chose to add the mod to your whitelist to allow the player to join with that mod.
It will also block liteloader mods and pixel/poke radar.
Is it foolproof?
Not by any means, but it will be a huge help in stopping people from joining your server with a mod such as X-Ray. It will block any unknown Forge mod and the 1.12 version will also block lite loader mods.
It has no way of knowing if someone is using an X-Ray Texture Pack. These should be able to be blocked by a simple plugin. Mirage if you're using Sponge and Anti Xray or Orebfuscator for Bukkit/Spigot.
You will need Modchecker to be both server-side and on the client. This video will guide you through how to get the mod working.
You can use this mod in your modpack, but you must give credit to GameGunner5 and myself (SleepingTea) and link back to this page.