Unknown Detection Party

A Minecraft Cheat in NodeJS

Nothing big, just a small intro for (s)kids wanting to make NodeJS clients (and no, this doesn't involve any Java code)

The code is a mess, mainly cause it's more of a POC to myself more than anything. I'll probably clean it up over the next few weeks, but don't hold me to that, cause there's a 50% chance it won't happen.

Happy skidding!

Requirements

• Python 2.x (! Not 3.x !)
• NodeJS and NPM
• JDK
• Minecraft 1.12 or 1.11 (Current mappings are for 1.11-1.12) (Or provide mappings in the correct format for other versions)

Getting Started

• If you haven't already, install NodeJS, NPM, and Python 2.x
• Create a new directory for the project
• Open a terminal in the root of your project (cmd, bash, whatever)
• Run npm install
• Create a new file called app.js, this will be the main file, and put the following inside:

  const fs = require('fs');
  const Util = require('./modules/util')();
  
  var running = true;
  
  var getShutdownThread = () => {
      var proxy = Util.getJvm().newProxy('java.lang.Runnable', { run: () => { running = false; } });
      return Util.getJvm().newInstanceSync('java.lang.Thread', proxy);
  };
  
  var startClient = () => {
      var Runtime = Util.importClass('java.lang.Runtime');
      var Main = Util.importClass('net.minecraft.client.main.Main');
      
      Runtime.getRuntimeSync().addShutdownHook(getShutdownThread());
      
      Main.main(Util.getJvm().newArray('java.lang.String', ['--version', 'udp', '--accessToken', '0', '--assetsDir', 'assets', '--assetIndex', Util.VERSION, '--userProperties', '{}']));
  };
  
  var launch = () => {
      Util.setupJVM();
      
      if (!fs.existsSync(Util.ABSOLUTE))
          return;
      
      process.chdir(Util.ABSOLUTE);
      
      startClient();
  };
  
  launch();

• Create a new directory called modules
• Create a new file in the modules directory called util.js, and put the following inside:

  const fs = require('fs');
  const appdata = require('appdata-path');
  const java = require('java');
  const Zip = require('adm-zip');
  
  module.exports = () => {
      var module = {};
      var classes = {};
      
      module.ABSOLUTE = `${appdata.getAppDataPath()}/.minecraft`;
      module.VERSION = '1.12';
      module.LIB_DIR = 'libraries';
      module.VER_DIR = `versions/${module.VERSION}`;
      module.NAT_DIR = `${module.VER_DIR}/${module.VERSION}-natives`;
      module.MAP_FILE = `./mappings/${module.VERSION}.json`;
      
      module.getAbsolute = (dir) => {
          return `${module.ABSOLUTE}/${dir}`;
      };
      
      module.setupJVM = () => {
          if (fs.existsSync(module.MAP_FILE))
              mapping = JSON.parse(fs.readFileSync(module.MAP_FILE));
  
          java.options.push(`-Djava.library.path=${module.NAT_DIR}`);
          java.classpath.push(`${module.getAbsolute(module.VER_DIR)}/${module.VERSION}.jar`);
  
          var json = JSON.parse(fs.readFileSync(`${module.getAbsolute(module.VER_DIR)}/${module.VERSION}.json`))
          if (json.libraries)
              json.libraries.forEach((lib) => {
                  if (lib) {
                      if (lib.downloads && lib.downloads.artifact && lib.downloads.artifact.path)
                          if (fs.existsSync(`${module.getAbsolute(module.LIB_DIR)}/${lib.downloads.artifact.path}`))
                              java.classpath.push(`${module.getAbsolute(module.LIB_DIR)}/${lib.downloads.artifact.path}`);
                      if (lib.extract && lib.natives) {
                          var natives = [lib.natives.linux, lib.natives.osx, lib.natives.windows];
                          natives.forEach((native) => {
                              if (native && lib.downloads && lib.downloads.classifiers && lib.downloads.classifiers[native] && lib.downloads.classifiers[native].path && fs.existsSync(`${module.getAbsolute(module.LIB_DIR)}/${lib.downloads.classifiers[native].path}`))
                                  new Zip(`${module.getAbsolute(module.LIB_DIR)}/${lib.downloads.classifiers[native].path}`).extractAllTo(`${module.getAbsolute(module.NAT_DIR)}`, true);
                          });
                      }
                  }
              });
      };
  
      module.getJvm = () => {
          return java;
      };
  
      module.importClass = (cls) => {
          if (classes[cls])
              return classes[cls];
          return classes[cls] = java.import(cls);
      };
      
      return module;
  }

After following the above, open a terminal in the directory of your app.js or whatever you desired to call it, and run node app, and watch the magic unfold!

Disclaimer

This does not currently allow you to log in with your Minecraft account, so for now it is just a proof of concept, but will eventually be more. It also doesn't run off your current install of Minecraft (it only requires specific files), so if you're wanting your saves, options, texturepacks, multiplayer stuff, then copy that over to your projects root directory