You’ve Completed a Smart Contract Audit — Now What?

Introduction

Smart contract auditing is a critical part of the development lifecycle, and it plays a crucial role in ensuring the security and integrity of a blockchain application. However, completing an audit is not the final step in securing a project; it’s just the beginning. They are not a “set-and-forget” solution. After an audit, developers and auditors must address audit findings, perform re-audits as needed, and implement ongoing monitoring strategies to ensure the long-term security of the project.

The results of an audit often include a mix of findings, ranging from trivial issues to potentially catastrophic vulnerabilities. How you handle these findings, decide whether to proceed with a re-audit, and implement continuous monitoring all play a significant role in your project’s long-term success and safety.

In this comprehensive guide, we’ll discuss the essential steps for addressing findings from a smart contract audit, re-audit considerations, and strategies for real-time monitoring. It will serve as a one-stop resource for developers and auditors to understand how to handle the post-audit process, ensuring that smart contracts remain secure and effective over time.

Understanding Audit Findings

Audit findings represent the vulnerabilities and issues discovered during the auditing process. They range in severity and require varying levels of action depending on the nature of the finding. Typically, audit findings can be divided into several categories, which help auditors and developers prioritize fixes and address the issues accordingly.

Severity Ratings

Audit firms typically categorize the severity of findings using a standardized rating system. Understanding this severity scale is crucial for developers when deciding which issues to address first.

• Critical: These findings must be fixed before deployment. They expose the contract to exploitation, which could result in significant financial losses or system breaches.
• High: These issues should be addressed as soon as possible. While not immediately exploitable, they can still lead to vulnerabilities compromising the contract’s functionality.
• Medium: These findings are not urgent but should be resolved soon.
• Low: These issues have minimal impact on security but should still be addressed as part of the contract refinement process.
• Informational: These are suggestions for improvement rather than actual vulnerabilities. They should be reviewed but don’t require immediate action.

Severity vs. Risk

While audit findings come with standardized severity ratings, the actual risk to your project depends heavily on context. A vulnerability’s true impact must be evaluated based on multiple factors specific to your project’s unique circumstances and requirements.

The assessment of risk begins with understanding your project’s exposure profile. Asset exposure plays a crucial role — consider not just the total value secured by the contract, but also the nature of these assets and their liquidity characteristics. A vulnerability in a contract handling highly liquid assets like ETH poses different risks compared to one managing locked governance tokens. The contract’s role in your ecosystem also shapes its risk profile. Core contracts that handle critical functionality or hold administrative powers warrant heightened scrutiny compared to peripheral features. Similarly, contracts with frequent user interactions or complex integration dependencies may face elevated risk levels even for seemingly minor vulnerabilities.

A “Medium” finding in a governance contract might be “High” if the contract holds significant treasury funds. Use a risk matrix to map likelihood vs. impact:

Prioritization Frameworks:

• Immediate Action: Critical/High findings with high likelihood.
• Post-Deployment Patches: Low-severity issues in non-core functions.

How to Address Findings

Addressing Critical Findings

Critical vulnerabilities must be addressed immediately, as they could result in significant breaches or financial loss. When encountering essential findings, the following steps should be taken:

1. Prioritize Fixing Critical Issues: Address critical vulnerabilities before deploying the contract. These vulnerabilities could result from logical errors, flaws in the smart contract code, or improper access control.
2. Collaboration with Auditors: Work closely with the auditing team to ensure the fix resolves the vulnerability and doesn’t introduce new problems.
3. Test the Fix: Once a fix is applied, conduct comprehensive testing, including unit testing and integration testing, to ensure that the problem is resolved and no new issues are introduced.
4. Communication: Inform stakeholders, including investors, about the issues and the steps to resolve them. Transparency is key to maintaining trust.

Examples:

• Re-entrancy vulnerabilities allowing unauthorized withdrawals.
• Access control bypasses.
• Integer overflow/underflow in critical functions.

Addressing High and Medium Findings

High- and medium-severity issues should be fixed promptly but do not necessarily require the same urgency as critical findings. These issues might not immediately expose the contract to an attack but could compromise its long-term security and robustness.

1. Address in Order of Priority: Address high and medium-severity issues once critical issues are fixed. Consider the potential impact of these vulnerabilities on the contract’s performance and safety.
2. Code Review: Review the proposed fixes to ensure they do not introduce new vulnerabilities. High and medium-severity issues often result from poor coding or adherence to best practices.
3. Test Thoroughly: After making the fixes, run tests to verify that the vulnerabilities have been addressed without negatively affecting other parts of the contract.

Examples (High Severity):

• Race conditions in DeFi protocols.
• Incorrect decimal handling in token transfers.
• Flawed price oracle implementations.

Examples (Medium Severity):

• Gas optimization issues affecting system usability.
• Inadequate event emissions.
• Minor mathematical precision losses.

Low Severity Findings

Low-severity issues are usually related to code quality, readability, or minor inefficiencies. While they don’t pose an immediate security risk, addressing them improves the codebase’s overall quality and maintainability.

1. Refactor the Code: Refactor the code to improve its readability, efficiency, and adherence to best practices.
2. Optimize Gas Usage: If the low-severity issues include gas optimization opportunities, address them to ensure the contract is as efficient as possible.
3. Review for Best Practices: Ensure the contract follows the latest Solidity best practices and coding standards.

Examples:

• Deprecated Solidity features.
• Incomplete documentation.
• Non-standard naming conventions.

Collaboration Between Developers and Auditors

Collaboration between developers and auditors is essential during the post-audit phase. After receiving the audit findings, developers should:

• Engage with the auditors: Discuss any findings that require clarification, particularly if the auditor’s suggestions conflict with the developer’s understanding or approach.
• Confirm Remediation: After applying fixes, ask auditors to verify the changes before moving to production. Some auditors offer a follow-up review after fixes have been applied.
• Continuous Feedback: Keep a feedback loop between the auditing and development teams to improve both the current contract and future audits.

What are the best practices for addressing audit findings?

Addressing audit findings effectively is crucial for ensuring the security and functionality of smart contracts. Here are some best practices to follow:

1. Thorough Review of Audit Reports

Review the audit report carefully to understand the identified vulnerabilities and their implications. Each finding should be categorized based on severity — critical, high, medium, or low. This prioritization helps in focusing efforts on the most pressing issues first.

2. Assign Responsibilities

Designate specific team members to be responsible for addressing each finding. This ensures accountability and helps streamline the remediation process — clear communication about who is responsible for what can prevent overlaps and gaps in addressing issues.

3. Implement Fixes Promptly

Once responsibilities are assigned, implement the necessary code changes to address the findings. This may involve rewriting sections of the smart contract, optimizing for gas efficiency, or enhancing security measures. It is essential to ensure that the fixes do not introduce new vulnerabilities.

4. Conduct Internal Testing

After implementing fixes, conduct thorough internal testing. This should include unit, integration, and regression tests to ensure the changes work as intended and do not break existing functionality. Testing should also cover edge cases to ensure robustness.

5. Retest and Validate

Once the fixes are implemented and tested, consider having the code reviewed again through a second internal review or by an external auditor. This step is crucial to validate that all identified issues have been adequately addressed and that no new vulnerabilities have been introduced.

6. Document Changes

Maintain detailed documentation of all changes made in response to the audit findings. This documentation should include the original issue, the steps to resolve it, and any testing performed. This not only aids in future audits but also provides a clear record for stakeholders.

7. Plan for Re-Audits

Schedule re-audits, especially after significant changes to the smart contract. Regular audits help maintain a strong security posture and ensure the contract complies with best practices and evolving security standards.

8. Implement Real-Time Monitoring

After addressing the findings, set up real-time monitoring for the smart contract. This allows for ongoing oversight of the contract’s performance and can alert the team to any unusual activities or potential breaches, enabling quick responses to emerging threats.

9. Educate the Team

Ensure all team members know the common vulnerabilities and best practices in smart contract development. Regular training sessions help keep the team updated on the latest security trends and techniques.

Re-auditing a Contract with Major Changes

When making significant changes to a contract that has already been audited, follow these steps:

1. Document Changes Clearly: Provide a clear and comprehensive summary of the changes made to the auditors. Include code diffs and explanations to help the auditors focus on the relevant parts of the contract.
2. Retest the Contract: Run tests on the modified contract to ensure that the changes do not break existing functionality and that the fixes have resolved the original vulnerabilities.
3. Schedule the Re-audit: Once the changes are implemented and tested, schedule a re-audit with the same or a new auditing firm to ensure all new changes are thoroughly checked.
4. Confirm Fixes: After the re-audit, confirm that the previous findings have been addressed and that no new vulnerabilities have been introduced.

Scheduling and Managing Re-audits

Re-audits can be time-consuming and expensive. To manage the process effectively:

• Plan Ahead: Ensure the development team has enough time to make the necessary changes before the re-audit begins.
• Allocate Resources: Consider allocating resources for multiple re-audit rounds if the contract undergoes significant changes.
• Coordinate with Auditors: Keep an open line of communication with the auditors to avoid any delays in scheduling.

How to Ensure Re-audit Efficiency

To make the re-audit process more efficient:

• Clear Documentation: Provide auditors with well-documented code, change logs, and explanations of the changes made.
• Review Recommendations: Before requesting a re-audit, review any findings from the previous audit and fix any remaining issues.

​​Reading Between the Lines

Experienced developers know that audit reports often contain subtle indicators of broader issues:

Pattern Recognition:

• Multiple related findings might indicate systemic architectural problems.
• Similar issues across different components suggest development process gaps.

Context Evaluation:

• Consider findings about your specific use case.
• Evaluate risk levels based on your deployment environment.

Hidden Implications:

• Look for potential interactions between seemingly unrelated findings.
• Consider the second-order effects of proposed fixes.

Conclusion

Post-audit security is a continuous cycle of remediation, vigilance, and adaptation. By institutionalizing rigorous re-audits, real-time monitoring, and a security-first culture, teams can mitigate risks in the fast-evolving Web3 landscape. Remember: An audit is a snapshot; resilience is built daily.

Olympix: Your Partner in Secure Smart Contracts

Olympix provides advanced Solidity analysis tools to help developers identify and fix vulnerabilities before they become critical exploits.

Get started today to fortify your smart contracts and proactively shield them from exploits in the evolving Web3 security landscape.

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