[Paper Review] Exploring the Attack Surface of Blockchain: A Systematic Overview

Muhammad Saad, Jeffrey Spaulding+5 more|arXiv (Cornell University)|Apr 6, 2019

Blockchain Technology Applications and Security148 references103 citations

TL;DR

This paper systematically surveys the public blockchain attack surface, categorizing attacks by blockchain design, peer-to-peer architecture, and application context, and discusses defenses and inter-attack relationships.

ABSTRACT

In this paper, we systematically explore the attack surface of the Blockchain technology, with an emphasis on public Blockchains. Towards this goal, we attribute attack viability in the attack surface to 1) the Blockchain cryptographic constructs, 2) the distributed architecture of the systems using Blockchain, and 3) the Blockchain application context. To each of those contributing factors, we outline several attacks, including selfish mining, the 51% attack, Domain Name System (DNS) attacks, distributed denial-of-service (DDoS) attacks, consensus delay (due to selfish behavior or distributed denial-of-service attacks), Blockchain forks, orphaned and stale blocks, block ingestion, wallet thefts, smart contract attacks, and privacy attacks. We also explore the causal relationships between these attacks to demonstrate how various attack vectors are connected to one another. A secondary contribution of this work is outlining effective defense measures taken by the Blockchain technology or proposed by researchers to mitigate the effects of these attacks and patch associated vulnerabilities

Motivation & Objective

• Survey the security vulnerabilities of blockchain systems across design constructs, architecture, and applications.
• Explain how attacks originate and propagate through interconnected vectors.
• Map relationships between different attacks to reveal compound risks and defense points.
• Summarize defense strategies proposed in the literature and identify open problems and future directions.

Proposed method

• Classify attack vectors into three broad categories: design constructs (forks, stale/orphaned blocks), peer-to-peer architecture (51% attack, DDoS, DNS/BGP/eclipse attacks, consensus delays), and application context (wallet theft, smart contract DoS, double-spending).
• Analyze causal relationships to show how one attack can enable others.
• Survey existing defense mechanisms proposed in the literature corresponding to each attack class.
• Present an integrated view of the attack surface and discuss combined countermeasures and future research directions.

Experimental results

Research questions

• RQ1 What are the primary attack classes in public blockchain systems stemming from design, network, and application contexts?
• RQ2 How do attacks in one class enable or influence other attack vectors across the blockchain stack?
• RQ3 What defense strategies have been proposed for each attack class, and where are the open problems?
• RQ4 How do forks and consensus dynamics impact security and reliability of blockchain applications?

Key findings

• Attacks are organized around three factors: blockchain cryptographic constructs, distributed architecture, and application context.
• Notable attacks include forks, orphaned and stale blocks, 51% majority attacks, DDoS, DNS/BGP/eclipse attacks, consensus delay, wallet theft, smart contract DoS, and replay/reentrancy/overflow attacks.
• There are causal links showing how certain attacks can facilitate others, highlighting the value of unified defense strategies.
• Public blockchains face higher attack opportunities due to a weak trust model, whereas private/permissioned blockchains reduce exposure but have different performance and security trade-offs.
• The paper compiles defense measures proposed in prior work and discusses combined countermeasures and directions for secure, scalable blockchain designs.