Steam-Fi Pre-Vault - Tea-Fi

1. Introduction

TeaFi engaged Halborn to conduct a security assessment on their smart contracts beginning on September 15th, 2025 and ending on September 23th, 2025. The scope of this assessment was limited to the smart contracts provided to the Halborn team. Commit hashes and additional details are documented in the Scope section of this report.

SteamFi Pre-Vaults manage user staking positions with modular StakingStrategy and RewardStrategy contracts, allowing flexible protocol integrations and reward logic. The system supports native/ERC-20 assets, on-behalf operations via EIP-712, and robust lifecycle management (stake → unstake → withdraw) with cooldowns, granular pause controls, and security safeguards.

2. Assessment Summary

Halborn was provided 7 days for the engagement and assigned 1 full-time security engineer to review the security of the smart contracts in scope. The engineer is a blockchain and smart contract security expert with advanced penetration testing and smart contract hacking skills, and deep knowledge of multiple blockchain protocols.

The purpose of the assessment is to:

• Identify potential security issues within the smart contracts.

• Ensure that smart contract functionality operates as intended.

In summary, during the assessment Halborn identified several areas for improvement to reduce both the likelihood and impact of potential risks, which were mostly addressed by the TeaFi team. The primary suggestions include:

• Decoupling the reward claiming mechanism from the withdrawal process to prevent permanent reward forfeiture.

• Modify the reward calculation logic to account for the full period, ensuring users receive rewards until positions are actually withdrawn.

• Update _receiveAssets() to refund excess ETH to msg.sender instead of from.

• Implement a mechanism to track and close underlying protocol positions upon user withdrawal.

• Replace manual price updates with automated oracle feeds to eliminate admin-triggered frontrunning opportunities.

  
  

3. Test Approach and Methodology

Halborn performed a combination of manual code review and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of this assessment. While manual testing is essential to uncover flaws in logic, process, and implementation, automated testing techniques enhance coverage of smart contracts and can quickly identify issues that do not follow security best practices.

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

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

• Manual code review and walkthrough of the smart contracts to identify potential logic issues.

• Manual testing of all core functions, including supply, withdraw, repay, and borrow, to validate expected behavior and identify edge-case vulnerabilities.

• Local testing to simulate contract interactions and validate functional and security assumptions.

• Local deployment and testing with Foundry.