Decentralized finance (DeFi) in Ethereum is a financial ecosystem built on the blockchain that has locked over 200 billion USD until April 2022. All transaction information is transparent and open when transacting through the DeFi protocol, which has led to a series of attacks. Several studies have attempted to optimize it from both economic and technical perspectives. However, few works analyze the vulnerabilities and optimizations of the entire DeFi system. In this paper, we first systematically analyze vulnerabilities related to DeFi in Ethereum at several levels, then we investigate real-world attacks. Finally, we summarize the achievements of DeFi optimization and provide some future directions.

翻译：Etheum的分散化金融(DeFi)是一个金融生态系统,其基础是直到2022年4月之前锁定了2 000多亿美元的链条。所有交易信息在通过DeFi协议进行交易时都是透明和公开的,这导致了一系列攻击。一些研究试图从经济和技术角度优化它。然而,很少有工作分析整个DeFi系统的脆弱性和优化。在本文中,我们首先系统分析与Etheum DeFi有关的几个层次的脆弱性,然后调查真实世界的攻击。最后,我们总结了DeFi优化的成就并提供了一些未来方向。