This tool is no longer necessary mojang has released its own patch which should cover everyone who is affected https://www.minecraft.net/en-us/article/important-message--security-vulnerability-java-edition

THIS EXPLOIT EFFECTS BOTH CLIENTS AND SERVERS

There is currently a exploit going around that affects all versions of Minecraft this exploit abuses log4j deserialization in order to achieve remote code execution this exploit is not new but has only just recently come to light because of paper mc and spigot etc patching and announcing this exploit

Only use this tool if the client you use hasnt already been patched as this may make clients like Lunar client not work

Currently the only available releases for this patcher are Jar releases but binaries will be available soon

Please update your servers to the latest version to help protect against this most major providers have already patched this vulnerability HOWERVER this is still unpatched on all minecraft clients

This tool is too help patch clients and protect them against the vuln because they are all vulnerable all an attack has to do is put a payload in the game chat an all connected clients will be affected

THIS IS NOT A PERMANENT SOLUTION THIS ONLY IS A ONE TIME PATCH ON EACH CLIENT JAR UPDATING YOUR MC VERSIONS OR INSTALLING NEW ONES WILL NOT BE AFFECTED BY THIS PATCH AND YOU WILL NEED TO RUN IT AGAIN

This patch modifies each of the log file configurations in your mc jars replacing

%msg with %msg{nolookups}

Releases will be available in the releases tab