MC-Log4J-Exploit-Checker

Checks your Minecraft logs folder (including zipped logs) to potentially see if you've been a victim of the recent Log4J exploit!
You can now also check your MultiMC logs on all platforms alongside Badlion & Lunar client logs on Windows!

See how to use this, capabilities and more in this README.

Please also read the disclaimer at the bottom of this README file.

Capabilities

What can this do?

This tool it capable of detecting if someone has attempted to use this exploit on you.
This tool can go through your logs, and it does unzip any zipped (.gz) logs automatically in order to check them aswell.
This tool is also able to tell you what files the exploit was detected in and tells you the lines that it detected the exploit on.

What can't this do?

This tool can not determine for certain that you were not a victim of the exploit.
This tool also can not determine, if any, what code was run by the exploit nor the severity of it.

So what is the purpose of this tool?

Just because this tool can not certainly tell you if you were affected, it can tell you if any attempts were made whether or not they were successful.
This tool allows you to take action now instead of waiting for something bad to potentially happen.

Usage

Compiled Jar and other files can be downloaded from Releases

Windows

If on Windows you can run this two separate ways:
Method 1: Downloading LogChecker.exe from Releases and run it

OR if you don't trust random .exe files, and you shouldn't, you can use Method 2.

Method 2: Download LogChecker.jar and start.bat from Releases, make sure they're both in the same folder, then run start.bat

Mac/Linux

Simply download LogChecker.jar and run it in a terminal/console/whatever you guys call it!
I haven't tested this on either platform but, I added premade selections for both platforms as follows.
~/Library/Application Support/minecraft Mac Default
~/.minecraft Linux Default

Notes

1. I put this together fairly quickly, if you have any suggestions or issues then please open an Issue on GitHub or contact me via Discord (Koupah#5129)
2. The LogChecker.exe is just a wrapped Jar file, you still need Java to run it
3. You do not have to run my compiled jar file. I encourage you to look through the source and compile it yourself. It's all here.
4. You may also run LogChecker.jar with an additional argument to specify your .minecraft folder location

Disclaimer

If there are no results it doesn't guarantee you were not affected as some attackers could have modified your logs.
You have to remember that this is Minecraft, most attackers are more than likely script kiddies copy and pasting an exploit someone else has provided them. In a lot of cases they won't clear/modify your logs.

If attempts at the exploit are found, it is your duty to investigate them and determine if they were successful, malicious, etc.

I am not responsible for any actions you may or may not take after using my tool.
It is not my responsibility if you rely solely upon this tool to determine if you were affected.