基于符号执行的智能合约漏洞检测方案

随着区块链技术的应用推广，智能合约的数量呈现爆发式增长，而智能合约的漏洞将给用户带来巨大损失。但目前研究侧重于以太坊智能合约的语义分析、符号执行的建模与优化等，没有详细描述利用符号执行技术检测智能合约漏洞流程，以及如何检测智能合约常见漏洞。为此，在分析以太坊智能合约的运行机制和常见漏洞原理的基础上，利用符号执行技术检测智能合约漏洞。首先基于以太坊字节码构建智能合约执行控制流图，再根据智能合约漏洞特点设计相应的约束条件，利用约束求解器生成软件测试用例，检测常见的整型溢出、权限控制、Call注入、重入攻击等智能合约漏洞。实验结果表明，所提检测方案具有良好的检测效果，对Awesome-Buggy-ERC20-Tokens漏洞库中70份含漏洞的智能合约的漏洞检测正确率达85%。

Smart contract vulnerability detection scheme based on symbol execution

Smart contract is one of the core technologies of blockchain,and its security and reliability are very important. With the popularization of blockchain application,the number of smart contracts has increased explosively. And the vulnerabilities of smart contracts will bring huge losses to users. However,the current research focuses on the semantic analysis of Ethereum smart contracts,the modeling and optimization of symbolic execution,and does not specifically describe the process of detecting smart contract vulnerabilities using symbolic execution technology,and how to detect common vulnerabilities in smart contracts. Based on the analysis of the operation mechanism and common vulnerabilities of Ethereum smart contract,the symbol execution technology was used to detect vulnerabilities in smart contracts. Firstly,the smart contract control flow graph was constructed based on Ethereum bytecode,then the corresponding constraint conditions were designed according to the characteristics of smart contract vulnerabilities,and the constraint solver was used to generate software test cases to detect the common vulnerabilities of smart contracts such as integer overflow,access control,call injection and reentry attack. The experimental results show that the proposed detection scheme has good detection effect, and has the accuracy of smart contract vulnerability detection up to 85% on 70 smart contracts with vulnerabilities in Awesome-Buggy-ERC20-Tokens.