Impact of Proposer-Builder Separation Paradigm on Sandwich Attacks in Ethereum Blockchain

• Josué N. Campos UFV http://orcid.org/0000-0001-9630-0064
• Isdael R. Oliveira UFPI
• Alexandre Fontinele UFPI
• Glauber D. Gonçalves UFPI
• Alex B. Vieira UFJF https://orcid.org/0000-0003-0821-126X
• José Augusto M. Nacif UFV https://orcid.org/0000-0003-0703-5620

DOI: https://doi.org/10.5753/sbrc.2025.6357

Abstract

Maximal Extractable Value (MEV) has emerged as a important practice in Ethereum DeFi ecosystem. MEV practices allow traders to maximize their profits by reordering, inserting, or blocking transactions within a block. Recently, the Ethereum implemented the Proposer-Builder Separation (PBS) paradigm, splitting the role of miners into builder and validator nodes. Despite this new design, the MEV phenomenon persists. In this paper, we investigate the sandwich attack, a special MEV practice based on price manipulation through front-running techniques, in Ethereum Blockchain under the PBS paradigm. Our analysis covered over 1 million blocks throughout 2023, where we identified approximately 1.5 million sandwich attacks, with an average profit of $3.2K for the attackers. Our results show that PBS has contributed to encouraging sandwiching activities, as attackers typically pay the highest fees to block builders, around 60% of blocks according to our measurements. Furthermore, we found that few builders benefit from sandwich attacks. In this case, only 4 builder nodes received more than 70% of the attackers’ fees in 2023.

Keywords: Sandwich Attack, Blockchain, Ethereum, MEV, PBS

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