wkrakmi

A Rust program to generate lightweight and standalone WebAssembly crackmes for Capture The Flag platforms.

Usage

Modify the challenge function in challenge.rs in order to choose your own challenge difficulty.

Make sure you have rust toolchain installed and up to date.

If not, install Rust toolchain:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Download the wasm-bindgen-cli and basic-http-server crates.

cargo install basic-http-server wasm-bindgen-cli

wasm-bindgen and cargo versions must match, make sure cargo is up to date:

cargo update

Add wasm to rustup targets:

rustup target add wasm32-unknown-unknown

Then, run the build.sh script. It will compile the Rust code to WebAssembly, and run the challenge on 127.0.0.1:4000.

If you don't want to download basic-http-server with cargo, you can still run the challenge with the following Python script:

import http.server
import socketserver

PORT = 4000

Handler = http.server.SimpleHTTPRequestHandler
Handler.extensions_map.update({
    '.wasm': 'application/wasm',
})

socketserver.TCPServer.allow_reuse_address = True
with socketserver.TCPServer(("", PORT), Handler) as httpd:
    httpd.allow_reuse_address = True
    print("serving at port", PORT)
    httpd.serve_forever()

Tips for sharing the challenge online

Using ngrok, you can share the challenge online:

ngrok http 4000

It will generate a link on which the challenge will be hosted publicly.