Paper 2023/1855

Demystifying DeFi MEV Activities in Flashbots Bundle

Zihao Li, Hong Kong Polytechnic University
Jianfeng Li, Xi'an Jiaotong University
Zheyuan He, University of Electronic Science and Technology of China
Xiapu Luo, Hong Kong Polytechnic University
Ting Wang, Pennsylvania State University
Xiaoze Ni, University of Electronic Science and Technology of China
Wenwu Yang, University of Electronic Science and Technology of China
Xi Chen, University of Electronic Science and Technology of China
Ting Chen, University of Electronic Science and Technology of China

Decentralized Finance, mushrooming in permissionless blockchains, has attracted a recent surge in popularity. Due to the transparency of permissionless blockchains, opportunistic traders can compete to earn revenue by extracting Miner Extractable Value (MEV), which undermines both the consensus security and efficiency of blockchain systems. The Flashbots bundle mechanism further aggravates the MEV competition because it empowers opportunistic traders with the capability of designing more sophisticated MEV extraction. In this paper, we conduct the first systematic study on DeFi MEV activities in Flashbots bundle by developing ActLifter, a novel automated tool for accurately identifying DeFi actions in transactions of each bundle, and ActCluster, a new approach that leverages iterative clustering to facilitate us to discover known/unknown DeFi MEV activities. Extensive experimental results show that ActLifter can achieve nearly 100% precision and recall in DeFi action identification, significantly outperforming state-of-the-art techniques. Moreover, with the help of ActCluster, we obtain many new observations and discover 17 new kinds of DeFi MEV activities, which occur in 53.12% of bundles but have not been reported in existing studies.

Note: This submission serves as our full paper version with the appendix.

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Publication info
Published elsewhere. Major revision. Proceedings of the 2023 ACM SIGSAC Conference on Computer and Communications Security
DeFiSmart contractMiner Extractable ValueFlashbots Bundle
Contact author(s)
cszhli @ comp polyu edu hk
2023-12-04: approved
2023-12-03: received
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Creative Commons Attribution-NonCommercial-NoDerivs


      author = {Zihao Li and Jianfeng Li and Zheyuan He and Xiapu Luo and Ting Wang and Xiaoze Ni and Wenwu Yang and Xi Chen and Ting Chen},
      title = {Demystifying DeFi MEV Activities in Flashbots Bundle},
      howpublished = {Cryptology ePrint Archive, Paper 2023/1855},
      year = {2023},
      doi = {10.1145/3576915.3616590},
      note = {\url{}},
      url = {}
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