# 🪡 jNeedle (or Needle)

Yet another jar malware detection tool

Quickstart / How to use

If you came from MMPA or already know what this program does, look here to see how to use jNeedle.

GUI (Graphical) mode

The easiest way to use jNeedle is to use the GUI version. Just download the jneedle-gui-xxx.jar from the release page and double click on it.

Help, it won't start!

There currently is a bug with Java 1.8, which won't let the program start. This is known and will be fixed in the future.

CLI mode

If you want to use the CLI version, you have to download the jneedle-xxx-fat.jar from the release page and run it with the following command:

java -jar jneedle-xxx-fat.jar -f <path to jar or directory>

JNeedle will then check the given file or directory for malicious code. It gives a summary of the results at the end.

Help, where do I need to put that command?
On Windows, open the file explorer, navigate to the folder where you downloaded the jar file. Hold Shift and right click on empty space. Select Open PowerShell window here and type the command above.

Help, it won't start!
See the GUI section for more information.

For more CLI arguments, type the command without -f:

> java -jar .\jneedle-1.0.0.jar
Value for option --file should be always provided in command line.
Usage: jNeedle options_list
Options:
    --file, -f -> file or directory (always required) { String }
    --url, -u [https://maven.kosmx.dev/dev/kosmx/needles] { String }
    --dblocation [C:\Users\kosmx\.jneedle] { String }
    --threads [16] { Int }
    --help, -h -> Usage info

How to find the needle in a haystack? - Use a strong enough magnet

The detection tool is parsing jar .class files looking for signature instruction sequences. It is actually similar to string search:

Is the following sequence: "jump into the well" in the program:

exit house and lock door,
get the bus and to the shop to buy milk
jump into the well then get the bus
come home

See the light at the end of the tunnel

Attention! These are advanced options, which you probably won't need!
For an easy setup, look at the Quickstart section.

Add to PrismLauncher

Extra jar // recommended but harder to set-up

1. Check current launch classpath in the Version menu:
   Select the Fabric/Forge/Quilt/Minecraft (most bottom of these) and on the right menu, click Customize then Edit
2. This will open a text-editor, look for the mainClass entry in the class
   Fabrc for example: "mainClass": "net.fabricmc.loader.impl.launch.knot.KnotClient",
3. Save (copy) the entry value: net.fabricmc.loader.impl.launch.knot.KnotClient
4. close the editor and optionally click Revert in Prismlauncher
5. click Add to Minecraft.jar button and select jneedle.jar
6. Click edit while jneedle.jar is selected
7. Add the following to the json:
   "+jvmArgs": ["-Ddev.kosmx.jneedle.launchClass={launchClass}"], where you replace {launchClass} with the earlier saved class.
8. Add the following to the json:
   "mainClass": "dev.kosmx.needle.launchWrapper.ParameterizedWrapper",
9. Save the file and have fun!

The lines for specific launchers:
Quilt: "+jvmArgs": ["-Ddev.kosmx.jneedle.launchClass=org.quiltmc.loader.impl.launch.knot.KnotClient"],
Fabric: "+jvmArgs": ["-Ddev.kosmx.jneedle.launchClass=net.fabricmc.loader.impl.launch.knot.KnotClient"],
Forge up to 1.12.2: "+jvmArgs": ["-Ddev.kosmx.jneedle.launchClass=net.minecraft.launchwrapper.Launch"],
Forge from 1.13.2: "+jvmArgs": ["-Ddev.kosmx.jneedle.launchClass=io.github.zekerzhayard.forgewrapper.installer.Main"],

Easy path // slow but easy-to-setup

1. In the game version menu, click Add agents:
2. Select jneedle.jar
3. Done. (It will be slow in large modpacks)

JVM properties

Some parameter can be set as a JVM property:
-Ddev.kosmx.jneedle.remoteDatabase to set online database location.
-Ddev.kosmx.jneedle.remoteDatabase=https://maven.kosmx.dev/dev/kosmx/needles is default.

-Ddev.kosmx.jneedle.databasePath to set local database cache.
-Ddev.kosmx.jneedle.databasePath=${user.home}/.jneedle by default.

If using -cp jneedle.jar dev.kosmx.needle.launchWrapper.ParameterizedWrapper
-Ddev.kosmx.jneedle.launchClass to set the start class after checking is completed. The application has to be in classpath.
(This is for Minecraft wrapper use)

API usage:

<not yet in maven, I'll change that soon>
dev.kosmx.needle.CheckWrapper object (static class) has API functions:
These can be used from any JVM interop language (ideally Kotlin)
First call CheckWrapper.init() to initialize database. Optionally database location and file location can be specified

Then the program state is effectively immutable, calling check function is safe from any thread anytime.

CheckWrapper.checkJar() to check a single jar file (extension doesn't have to be jar)
CheckWrapper.checkPathBlocking() to check jar file or walk directory. Function will return with results once completed.

CheckWrapper.checkPath() with parameters to check path as a coroutine function. It can have feedback while running.
This function is kotlin only.