eth-challenge-base

xinetd docker for building ethereum contract challenges in capture the flag (CTF).

Getting Started

Quick Demo

Use the following command to run a quick demo:

docker run -it -p 20000:20000 -e WEB3_PROVIDER_URI=https://rpc.sepolia.org chainflag/eth-challenge-base
nc 127.0.0.1 20000

Usage

Create challenge project based on example

• The contracts directory is where you should code the challenge contract, specifically, you need to implement isSolved() function to check if it is solved.
• The challenge.yml file is the config for specifying challenge description, flag, contract name, constructor, gas limit etc. Refer to the comments in this file for more details.
• The .env file is used to set environment variables of docker container, including web3 provider, token secret and proof of work difficulty.

You can build multi-contract challenges by deploying contracts in a setup contract's constructor

Start serving your contract challenge

Use the following command to start serving the contract challenge:

docker run -d -p 20000:20000 --env-file .env -v `pwd`/contracts:/home/ctf/contracts -v `pwd`/challenge.yml:/home/ctf/challenge.yml chainflag/eth-challenge-base:0.9.3

Alternatively, you can use docker-compose:

docker-compose up -d

Advance

Use private PoA Ethereum network as challenge environment

1. Launch an anti-plagiarism PoA network by following the instructions here.
2. Keep the web3 provider defaults in the .env file.
3. Run the docker container using the following command:

docker run -d -p 20000:20000 --network geth_default --env-file .env -v `pwd`/contracts:/home/ctf/contracts -v `pwd`/challenge.yml:/home/ctf/challenge.yml chainflag/eth-challenge-base:0.9.3

Development

Prerequisites

Before you start, make sure you have the following installed:

• Docker
• Python3
• Required packages (pip install -r requirements.txt)

Run in development mode

1. Generate protobuf code and run server

make protoc
export WEB3_PROVIDER_URI="your web3 provider"
make dev

2. Open another terminal to run client

python run.py

Format python source

To format the Python source code, you will need to install additional packages (pip install -r requirements-dev.txt) and run the following command:

make format

License

Distributed under the MIT License. See LICENSE for more information.

Acknowledgements

• https://github.com/eth-brownie/brownie
• https://github.com/hitcxy/blockchain_template
• https://github.com/paradigm-operations/paradigm-ctf-2021
• https://github.com/balsn/proof-of-work