Towards Automated Security Analysis of Smart Contracts based on Execution Property Graph

2023  |  Kaihua Qin* · Zhe Ye* · Zhun Wang · Weilin Li · Liyi Zhou · Chao Zhang · Dawn Song · Arthur Gervais  |

Identifying and mitigating vulnerabilities in smart contracts is crucial, especially considering the rapid growth and increasing complexity of DeFi platforms. To address the challenges associated with securing these contracts, we introduce a versatile dynamic analysis framework specifically designed for the EVM. This comprehensive framework focuses on tracking contract executions, capturing valuable runtime information, while introducing and employing the EPG to propose a unique graph traversal technique that swiftly detects potential smart contract attacks. Our approach showcases its efficacy with rapid average graph traversal time per transaction and high true positive rates. The successful identification of a zero-day vulnerability affecting Uniswap highlights the framework's potential to effectively uncover smart contract vulnerabilities in complex DeFi systems…

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SoK: Decentralised Finance (DeFi) Attacks

2023  |  Liyi Zhou · Xihan Xiong · Jens Ernstberger · Stefanos Chaliasos · Zhipeng Wang · Ye Wang · Kaihua Qin · Roger Wattenhofer · Dawn Song · Arthur Gervais  |  |  IEEE S&P 2023

We investigate 77 academic papers, 30 audit reports, and 181 real-world incidents. Our open data reveals several gaps between academia and the practitioners' community. For example, few academic papers address "price oracle attacks" and "permissonless interactions", while our data suggests that they are the two most frequent incident types (15% and 10.5% correspondingly). We also investigate potential defenses, and find that: (i) 103 (56%) of the attacks are not executed atomically, granting a rescue time frame for defenders; (ii) SoTA bytecode similarity analysis can at least detect 31 vulnerable/23 adversarial contracts; and (iii) 33 (15.3%) of the adversaries leak potentially identifiable information by interacting with centralized exchanges…

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Blockchain Large Language Models

2023  |  Yu Gai* · Liyi Zhou* · Kaihua Qin · Dawn Song · Arthur Gervais  |

This paper presents a dynamic, real-time approach to detecting anomalous blockchain transactions. The proposed tool, BlockGPT, generates tracing representations of blockchain activity and trains from scratch a large language model to act as a real-time Intrusion Detection System. Unlike traditional methods, BlockGPT is designed to offer an unrestricted search space and does not rely on predefined rules or patterns, enabling it to detect a broader range of anomalies. We demonstrate the effectiveness of BlockGPT through its use as an anomaly detection tool for Ethereum transactions. In our experiments, it effectively identifies abnormal transactions among a dataset of 68M transactions and has a batched throughput of 2284 transactions per second on average. Our results show that, BlockGPT identifies abnormal transactions by ranking 49 out of 124 attacks among the top-3 most abnormal transactions interacting with their victim contracts. This work makes contributions to the field of blockchain transaction analysis by introducing a custom data encoding compatible with the transformer architecture, a domain-specific tokenization technique, and a tree encoding method specifically crafted for the Ethereum Virtual Machine (EVM) trace representation…

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