Krunker Decompiler

See an example

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Quickstart

1. Get the repository & dependencies

git clone https://github.com/e9x/krunker-decompiler.git
cd krunker-decompiler
npm install

2. Build the decompiler

npm run build

2. Get the game source

   [user@linux krunker-decompiler]$ cat ../krunker.05.12.23.js
   (function(iÌïiîií,iÏïïîiî){var iIiííìi=a3iíiíîiî,iÎìîìíì=iÌïiîií();while(!![]){try{var iIiiîîí=-parseInt(iIiííìi(0xc99))/0x1*(-parseInt(iIiííìi(0x172c))/0x2)+parseInt(iIiííìi(0xc3e))/0x3*(parseInt(iIiííìi(0x1623))/0x4)+-parseInt(iIiííìi(0x40a))/0x5+parseInt(iIiííìi(0x19b1))/0x6+-parseInt(iIiííìi(0x4888))/0x7+-parseInt(iIiííìi(0x45f8))/0x8*(-parseInt(iIiííìi(0xc7d))/0x9)+-parseInt(iIiííìi(0x2d1a))/0xa*(parseInt(iIiííìi(0x2699))/0xb);if(iIiiîîí===iÏïïîiî)break;else iÎìîìíì['push'](iÎìîìíì['shift']());}catch(iÏiîiií){iÎìîìíì['push'](iÎìîìíì['shift']());}}}(a3iìiìïìi,0x7bbf4),function(iïíîïii){var iiïîììí=(function(){var iiíiìií=!![];return function(iîìiíiì,iîiìiìî){var iiïîiìí=iiíiìií?function(){if(iîiìiìî){var iíïîïïí=
   

   Make sure your source:

   • Is not wrapped in an anonymous function You can modify the source to remove the wrapper.

   (function anonymous(b475796ed633d5fd0485
   ) {
   
   (/* source goes here */)
   })

• Starts with a newline This is to match the real bundle. The bundle itself starts with a newline. However, this is optional.

3. Deobfuscate the source

   This will deobfuscate the soruce and split each module into an individual file.

   npm run deobfuscate ../krunker.js

4. Process the modules

   This will undo all minifications to the source and rename the variables.

   npm run process

You can find the result in the processed directory.

Get the game source (Chromium)

1. Go to Krunker
2. Open devtools
3. Refresh the tab
4. Click on "Network"
5. Find "seek-game?hostname=krunker.io..."
6. Click on "Initiator"
7. Click on the link to "VM XXX:X" A VM is a JavaScript virtual machine. It's assigned a number for debugging.
8. Wait for the VM's source to load. This may take up to 5 minutes depending on your machine.
9. Right click the tab in the source viewer. It should be named "VM XXX"
10. Select "Save as..."
11. Enter a name that ends with .js, like krunker.js
12. Close Devtools and Krunker

Fixing the source for use in the decompiler

Because the source is wrapped in a way that the decompiler doesn't understand, you'll have to modify it.

1. Open the source in an editor capable of handling an 8 MB file Like VS Code.

2. Remove the first 2 lines:

   (function anonymous(b475796ed633d5fd0485
   ) {

3. Remove the last line:

   })

4. Save

How to find the Webpack entry point

Entry point is named index.js in the processed folder.

How to decompile other files (Not Krunker/Webpack)

This tool can be used against other scripts that aren't bundled with Webpack. For example, you might want to use this to rename variables or deobfuscate code in a script.

1. Build the program (if you haven't already)

   npm install
   npm run build

2. Run the processCode script

   npm run processCode "function _0x1e3586(x,y){return x+y}exports.test = _0x1e3586;"

   Ideally, the output should go to a file.

   npm run processCode "..." output.js

   See output.js in the folder.

For additional usage, run npm run processCode without any parameters.