Huma Protocol Update - Huma Finance

1. Introduction

Huma engaged Halborn to conduct a security assessment on a set of changed in their Huma Protocol Solana program beginning on November 25th, 2024, and ending on November 27th, 2024. The security assessment was scoped to the Solana Program provided in huma-solana-programs GitHub repository. Commit hashes and further details can be found in the Scope section of this report.

The changes made to the protocol are intended to address the potential lack of redemption requests submissions by lenders when the lock-in period expires. To this end, a field, has been integrated, which allows the Sentinel service to submit the repayment request on behalf of lenders when activated, ensuring that this Sentinel service account cannot withdraw money on behalf of the user. Funds from processed refund requests will continue to be withdrawn by the lender.

An instruction has also been added to reallocate PoolConfig due to the size increase, and a padding field added to the end of the struct to account for future storage expansions.

2. Assessment Summary

Halborn was provided 3 days for the engagement and assigned two full-time security engineers to review the security of the Solana Programs in scope. The engineers are blockchain and smart contract security experts with advanced smart contract hacking skills, and deep knowledge of multiple blockchain protocols.

The purpose of the assessment is to:

• Identify potential security issues within the Solana Programs.

• Ensure that smart contract functionality operates as intended.

In summary, Halborn identified some improvements to reduce the likelihood and impact of risks, which should be addressed by the Huma team. The main ones were the following: 

• Add a validation in the add_redemption_request instruction handler to ensure that the delegate and delegated amount meets the expectations.

• Add a check in the add_redemption_request to ensure that the delegated amount meets the expected value when the flag is active.

• Reallocate all existing pools to the new format to ensure seamless operations.

• Allow the EA and pool treasury owner to call deposit without requiring delegation approval.

3. Test Approach and Methodology

Halborn performed a combination of a manual review of the source code and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of the program assessment. While manual testing is recommended to uncover flaws in business logic, processes, and implementation; automated testing techniques help enhance coverage of programs and can quickly identify items that do not follow security best practices.

The following phases and associated tools were used throughout the term of the assessment:

• Research into the architecture, purpose, and use of the platform.

• Manual program source code review to identify business logic issues.

• Mapping out possible attack vectors

• 
  

• Thorough assessment of safety and usage of critical Rust variables and functions in scope that could lead to arithmetic vulnerabilities.

• Scanning dependencies for known vulnerabilities (

  cargo audit

  ).
  

• Local runtime testing (

  anchor-test

  )