Securing Decentralized Finance: A Comprehensive Survey of Maximal Extractable Value and Its Countermeasures

The rapid advancement of blockchain network protocols has positioned decentralized finance (DeFi) as a key distributed application ecosystem in modern digital infrastructure. These distributed network systems are reshaping traditional financial paradigms by leveraging peer-to-peer protocols for accessible, transparent, and efficient services. However, the underlying network infrastructure faces significant security challenges, particularly concerning transaction manipulation within the framework of Maximal Extractable Value (MEV). MEV has emerged as a critical network security vulnerability due to its exploitation of transaction-ordering mechanisms in blockchain consensus protocols. Despite extensive research on MEV, critical gaps remain in understanding and securing distributed ledger networks against these vulnerabilities across various blockchain platforms. In this paper, we present a comprehensive survey of MEV within DeFi ecosystems through a multi-faceted approach. We provide a detailed taxonomy of MEV attack strategies targeting network protocol vulnerabilities. Furthermore, we offer a categorization of security countermeasures spanning consensus protocols, base-layer network design, and application-level defenses. Additionally, we present an empirical analysis of MEV dynamics across different blockchain networks, quantifying their impact on network performance, security, and fairness. This study contributes to enhancing the security of distributed network applications and advancing more robust and equitable network protocols for decentralized systems.