Security checklists for Ethereum smart contract development: patterns and best practices (2008.04761v1)

Abstract: In recent years Smart Contracts and DApps are becoming increasingly important and widespread thanks to the properties of blockchain technology. In most cases DApps are business critical, and very strict security requirements should be assured. Developing safe and reliable Smart Contracts, however, is not a trivial task. Several researchers have studied the security issues, however none of these provide a simple and intuitive tool to overcome these problems. In this paper we collected a list of security patterns for DApps. Moreover, based on these patterns, we provide the reader with security assessment checklists that can be easily used for the development of SCs. We cover the phases of design, coding, and testing and deployment of the software lifecycle. In this way, we allow developers to easily verify if they applied all the relevant security patterns to their smart contracts. We focus all the analysis on the most popular Ethereum blockchain, and on the Solidity language.

• The paper provides a structured guide with security checklists and best practices for enhancing Ethereum smart contract security across design, coding, and testing phases.
• The paper identifies 16 abstract security patterns, including proxy delegates and authorization models, to exemplify effective vulnerability mitigation.
• The checklists emphasize rigorous testing and cautious handling of external calls to prevent reentrancy and other common security exploits.

Overview of Security Checklists for Ethereum Smart Contract Development

The paper "Security checklists for Ethereum smart contract development: patterns and best practices" addresses an emergent need within the blockchain ecosystem to increase the security and reliability of smart contracts, particularly those on the Ethereum blockchain. As smart contracts and decentralized applications (DApps) become critical components in various sectors like finance, commerce, and supply chains, ensuring their security is paramount. The authors detail a methodological approach to compile a comprehensive set of security patterns and best practices aimed at fortifying smart contract development practices.

Contribution and Scope

The core contribution of this work lies in offering a structured guide for developers, comprising security assessment checklists applicable across different stages of Ethereum smart contract development: design, coding, and testing. The focus is exclusively on Ethereum, mainly because of its prevalent use and implementation of Turing-complete behavior using the Solidity programming language. This paper does not aim to solely enumerate vulnerabilities but goes further to propose actionable security patterns and best practices that can be rigorously applied throughout the development lifecycle of smart contracts.

Key Components

1. Abstract Security Patterns:

The paper identifies 16 abstract security patterns derived from a rigorous survey and synthesis of existing literature and community resources. Notable patterns include:

• Proxy Delegate (PD): Facilitates contract upgradeability by allowing a Proxy contract to redirect calls to different module addresses.
• Oracle (OR) & Reverse Oracle (RO): Adapts mechanisms for validating external data or sending blockchain data externally, ensuring the trustworthiness and reliability of the data input/output.
• Authorization (AU): Ensures that only authorized entities can execute sensitive contract functions, typically controlled through modifiers.

2. Design Phase Checklist:

The authors emphasize the importance of integrating fail-safe mechanisms and avoiding assumptions that a contract would always have zero balance. Emphasizing transaction ordering and multiple inheritance issues highlights the intricacies and potential pitfalls that developers must address in the design phase to prevent vulnerabilities inherently.

3. Coding Phase Checklist:

The checklists advocate for cautious handling of external calls, emphasizing the prevention of reentrancy attacks—a notorious vulnerability exposed by past hacks like the DAO exploit. Recommendations include embedding addresses to manage permissions securely, using hash-based mechanisms for anonymized authorization, and mitigating arithmetic errors through libraries like SafeMath.

4. Testing and Deployment Phase Checklist:

The emphasis on unit testing and deploying on test networks before transferring to the main network is underscored. Rigorous testing frameworks such as Truffle and Etherlime are recommended to ensure contracts are comprehensively vetted before deployment on the live Ethereum network.

Implications and Future Directions

The implications of adopting such structured security checklists in smart contract development are profound. Security incidents can lead to substantial financial losses and reputational damage, reiterating the need for robust security patterns. The patterns and checklists proposed contribute not only to enhancing the security posture of individual DApps but also to the broader security ecosystem of Ethereum smart contracts.

In future research avenues, extending these practices to different blockchain ecosystems outside Ethereum could yield insights into how blockchain-agnostic security frameworks could be established. Additionally, practical feedback from developers in deploying these checklists could refine and optimize the recommendations based on real-world application scenarios.

Conclusion

This paper effectively consolidates theoretical and practical security frameworks into actionable guides, offering a practical tool for developers in the secure development of Ethereum smart contracts. By proposing specific security patterns and checklists, this research work significantly contributes to the safe deployment and maintenance of smart contracts within the Ethereum ecosystem, which will likely have ongoing implications as blockchain technology proliferates.