A Novel Classification of Attacks on Blockchain Layers: Vulnerabilities, Attacks, Mitigations, and Research Directions (2404.18090v1)

Abstract: The widespread adoption of blockchain technology has amplified the spectrum of potential threats to its integrity and security. The ongoing quest to exploit vulnerabilities emphasizes how critical it is to expand on current research initiatives. Thus, using a methodology based on discrete blockchain layers, our survey study aims to broaden the existing body of knowledge by thoroughly discussing both new and known attack vectors inside the blockchain ecosystem. This survey proposes a novel classification of blockchain attacks and an in-depth investigation of blockchain data security. In particular, the paper provides a thorough discussion of the attack techniques and vulnerabilities that are specific to each tier, along with a detailed look at mitigating techniques. We reveal the deep dynamics of these security concerns by closely investigating the fundamental causes of attacks at various blockchain tiers. We clarify mitigation methods for known vulnerabilities and offer new information on recently developed attack vectors. We also discuss the implications of quantum computing in blockchain and the weaknesses in the current technology that can be exploited in the future. Our study advances the field of blockchain security and privacy research while also contributing to our understanding of blockchain vulnerabilities and attacks. This survey paper is a useful tool for readers who want to learn more about the intricacies of blockchain security. It also invites researchers to help strengthen blockchain privacy and security, paving the way for further developments in this dynamic and ever-evolving field.

• The paper classifies attacks across blockchain layers, identifying vulnerabilities in the Application, Contract, Consensus, Network, and Data layers.
• The paper highlights mitigation strategies such as reentrancy safeguards, decentralized consensus improvements, and robust cryptographic measures against quantum threats.
• The paper proposes future research directions focusing on quantum-resistant algorithms and integrated security protocols to future-proof blockchain systems.

A Novel Classification of Attacks on Blockchain Layers

Introduction

Blockchain technology has emerged as a transformative element of the digital space, integrating cryptography, consensus mechanisms, and decentralized networking to enhance the security and transparency of transaction logs. While mostly adopted in cryptocurrencies, blockchain is gaining traction across diverse industries such as healthcare, supply chain logistics, and digital identity management. Despite these promising applications, blockchain faces a multitude of security challenges, including attacks targeting various layers of its architecture. This paper categorizes and analyzes these attacks based on their targeted blockchain layers, suggesting mitigation strategies to enhance system resilience.

Overview of Blockchain

Blockchain is a decentralized ledger that records transactions across multiple computers. It guarantees the immutability and security of transaction data by utilizing peer-to-peer networks and consensus mechanisms. Each transaction is stored in a 'block' that forms a chain with other blocks through cryptographic hashes, creating a comprehensive and immutable transaction history. Blockchain networks vary in consensus mechanisms like PoW, PoS, and PBFT, influencing their security and efficiency.

Figure 1: Creation of a new block. After a transaction occurs, it gets submitted to the network. This transaction gets to the blockchain within a new block.

Layered Structure and Attack Classification

Blockchain architecture can be dissected into five layers: Application, Contract, Consensus, Network, and Data. Understanding vulnerabilities across these layers is crucial for categorizing and mitigating attacks efficiently.

Application Layer

The Application Layer involves user interfacing software. Vulnerabilities in the Application Layer often lead to attacks like Race Attack, Vector76, and Finney Attack, exploiting unconfirmed transactions. Mitigation involves ensuring transactions are verified multiple times by trusted miners before confirmation.

Contract Layer

Contracts enable complex interactions on blockchain, such as smart contracts for automated transaction processes. This layer must handle inputs proactively; failures here lead to attacks like Reentrancy and Short Address attacks. Best practices include mutex utilization and strict input validation to resist unauthorized manipulations.

Consensus Layer

The Consensus Layer ensures network-wide agreement on transaction validity and data integrity. Vulnerabilities such as blockchain centralization and forkability can lead to attacks like Selfish Mining and Nothing-At-Stake, suggesting the need for enhanced decentralization and strategic miner allocations as mitigations.

Network Layer

The Network Layer facilitates communication among blockchain nodes. It is prone to attacks through malicious nodes, such as Sybil Attacks and Timejacking. Preventing these attacks involves auditing node connections and using resource validation checks to assure node legitimacy.

Data Layer

Integrity and confidentiality of data stored on the blockchain are maintained using cryptographic signatures. Attacks on this layer include Replay and Dictionary Attacks, which exploit weak credential handling. Effective mitigations involve strong password policies and timestamping, creating cryptographic barriers to unauthorized access.

Figure 2: Attack classification based on different layers.

Attacks Description and Mitigation

Blockchain security threats are reviewed, focusing on their operation at each architectural layer. A tapestry of attacks such as Race, Vector76, Sybil, and Stalking are categorized alongside countermeasures aligned with their layer-specific vulnerabilities. Table \ref{summarytable} comprehensively summarizes this alignment, revealing nuances and interdependencies of blockchain security.

Figure 3: Blockchain forking. Mined blocks from User 1 and 2 get accepted by the blockchain simultaneously, leading to a fork. Subsequently, the longer chain is accepted, and fork is resolved.

Quantum Attacks and Mitigation on Blockchain

Quantum computing poses serious challenges to blockchain security by undermining current cryptographic protocols like RSA and ECDSA. Shor’s and Grover’s algorithms threaten transaction integrity and block validation efficiency. Two avenues exist to overcome these threats: post-quantum cryptography and quantum blockchains. Post-quantum cryptography suggests transitioning to quantum-resistant algorithms, while quantum blockchains could integrate quantum hardware directly into blockchain processes.

Figure 4: Potential quantum attack on a blockchain.

Future Research

While blockchain showed promising application potential, it remains vulnerable at every layer. Sustaining blockchain's growth will require ongoing research into deeper mitigation strategies that enhance security without compromising performance. Furthermore, quantum computing developments necessitate robust cryptographic solutions to address potential threats. Ultimately, proactive research and innovation will be key to securing blockchain's future.

Conclusion

This survey illuminates the complex landscape of blockchain attacks and mitigations, reinforcing understanding and strategic planning for blockchain-based systems. From evolving threats to quantum computing challenges, the paper emphasizes the necessity for comprehensive security protocols that anticipate future developments. Implementing robust measures across all blockchain layers will safeguard its transformative power.

Figure 5: Countermeasures against common attacks.