AntiCheat Plugin - Minecraft 🚀

Basic 1.8x plugin to detect cheaters in Minecraft Java Edition using the PacketEvents library.

📖 The original YouTube series can be found on YouTube

Supported Checks 🏹

The following checks below have been implemented:

⚔️ Combat	📦 Packet	🏃 Movement
AimA	Timer	NoFallA
KillauraA	Blink	NoFallB
KillauraB	Invalid Pitch	SpeedA
ReachA	PingSpoof
ReachB

Check Explanations ❓

Below check explanations for the first few episodes (the later episodes go more in-depth into explanation) can be found:

KillauraA:

• In vanilla Minecraft (1.8x), when a player moves or looks around, the client sends packets such as:

  • PLAYER_FLYING
  • PLAYER_POSITION
  • PLAYER_ROTATION to update its position and orientation.

• When players attack, the client sends an INTERACT_ENTITY packet. Due to:

  • Human reaction times
  • Network latency (lag)
  • The game's tick rate

  there is usually a delay of more than a few milliseconds between a movement update (PLAYER_FLYING) and an attack (INTERACT_ENTITY) packet.

• Many killaura cheats are designed to send attack packets almost immediately after the last movement update.

• This creates an abnormally short interval between:

  • The last PLAYER_FLYING packet
  • The INTERACT_ENTITY packet

• Our check detects this abnormally short interval to identify potential killaura behavior.

NoFall (A):

• Cheat clients can avoid taking fall damage by telling the server that they are on the ground, even when they aren't.

  • This is done by using the clientGround state.

• As the server, we can calculate a serverGround state by looking at the player's y position.

  • Finding a mismatch between clientGround and serverGround (while maintaining a buffer and 1-tick desync to avoid false flags) allows us to catch the cheater.

NoFall (B):

• Check for the default behavior of taking fall damage when falling from over 3 blocks.
  • If the player doesn't take fall damage and didn't land on a soft block like slime or water, then flag them.

Why does NoFall (A) detect Flight hacks sometimes?

• When flying off a solid block, our serverGround calculation (which checks if player's Y % 1/64 roughly = 0) remains true, while the clientGround becomes false because the player is now flying in the air. This causes NoFall (A) to flag.
• When falling a bit or jumping first before beginning to fly, NoFall (A) is not triggered because the player's Y becomes a weird decimal, so serverGround becomes false, which matches the clientGround. Thus, NoFall (A) is not an actual robust fly check, but the fly detection is simply a weird side effect of how we did our check.