[Paper Review] A Survey on Ethereum Systems Security: Vulnerabilities, Attacks and Defenses

Huashan Chen, Marcus Pendleton+2 more|arXiv (Cornell University)|Aug 13, 2019

Blockchain Technology Applications and Security96 references115 citations

TL;DR

A systematic survey that classifies Ethereum security into 44 vulnerabilities, 26 attacks, and 47 defenses across Ethereum’s layered architecture and environment, with root-cause analysis and future directions.

ABSTRACT

The blockchain technology is believed by many to be a game changer in many application domains, especially financial applications. While the first generation of blockchain technology (i.e., Blockchain 1.0) is almost exclusively used for cryptocurrency purposes, the second generation (i.e., Blockchain 2.0), as represented by Ethereum, is an open and decentralized platform enabling a new paradigm of computing --- Decentralized Applications (DApps) running on top of blockchains. The rich applications and semantics of DApps inevitably introduce many security vulnerabilities, which have no counterparts in pure cryptocurrency systems like Bitcoin. Since Ethereum is a new, yet complex, system, it is imperative to have a systematic and comprehensive understanding on its security from a holistic perspective, which is unavailable. To the best of our knowledge, the present survey, which can also be used as a tutorial, fills this void. In particular, we systematize three aspects of Ethereum systems security: vulnerabilities, attacks, and defenses. We draw insights into, among other things, vulnerability root causes, attack consequences, and defense capabilities, which shed light on future research directions.

Motivation & Objective

• Systematically categorize Ethereum security issues into vulnerabilities, attacks, and defenses across the Ethereum architecture and its environment.
• Identify root causes of vulnerabilities and map how attacks exploit them.
• Analyze the effectiveness and limitations of existing defenses and outline future research directions.
• Summarize practical best practices and design considerations for secure Ethereum-based systems.

Proposed method

• Adopts a layered Ethereum architecture (application, data, consensus, network, environment) to organize security topics.
• Enumerates 44 vulnerability types (V1–V44) and analyzes their root causes and current status (eliminated, best-practice avoidable, or open).
• Enumerates 26 attacks (A1–A26) and links them to associated vulnerabilities and consequences.
• Enumerates 47 defenses (D1–D47) and classifies them as proactive or reactive, with analysis of their capabilities and required investments.
• Uses Solidity, Solidity code practices, and client implementations (e.g., Geth, Parity) as focal technologies for security discussion.

Experimental results

Research questions

• RQ1 What are the major vulnerability classes in Ethereum and their root causes across architectural layers?
• RQ2 What attack techniques exploit these vulnerabilities and what are their consequences?
• RQ3 What defense mechanisms exist, how effective are they, and what gaps remain for securing Ethereum systems?
• RQ4 How can Ethereum security practices be structured to aid researchers and practitioners in preventing and mitigating attacks?

Key findings

• Ethereum introduces new vulnerability types not seen in traditional applications, driven by smart contracts and Ethereum design.
• There exists a broad set of 44 vulnerabilities, 26 attacks, and 47 defenses identified and analyzed.
• Vulnerabilities in the Ethereum environment are largely influenced by human, usability, and networking factors.
• Proactive defenses can mitigate many vulnerabilities, but reactive defenses cover fewer, with gaps in front-end and front-end–back-end interactions.
• Industry best practices can prevent many vulnerabilities if adequately applied.
• Attacks at the application layer (DApps) have caused significant financial losses, though some DoS-style and centralized-front-end issues also contribute to impact.