Smart Contract Assessment - Monetari

1. INTRODUCTION

Monetari engaged Halborn to perform a security assessment of their smart contracts from May 22nd, 2026 to May 29th, 2026. The assessment scope was limited to the smart contracts provided to Halborn. Commit hashes and additional details are available in the Scope section of this report.

The Monetari codebase in scope consists of smart contracts for a tokenized physical gold system (KGOLD) including an ERC-20 token representing grams of gold, a marketplace for buy/sell requests with KYC verification and dynamic gold-to-USDT pricing, a treasury for USDT custody, and administrative controls with dual-key pause/unpause and asset freeze mechanisms.

2. ASSESSMENT SUMMARY

Halborn was allocated 6 days for this engagement and assigned 1 full-time security engineer to conduct a comprehensive review of the smart contracts within scope. The engineer is an expert in blockchain and smart contract security, with advanced skills in penetration testing and smart contract exploitation, as well as extensive knowledge of multiple blockchain protocols.

The objectives of this assessment are to:

• Identify potential security vulnerabilities within the smart contracts.

• Verify that the smart contract functionality operates as intended.

In summary, Halborn identified several areas for improvement to reduce the likelihood and impact of security risks, which were partially addressed by the Monetari team. The main recommendations were:

• Consider re-reading the oracle inside _settlePurchase() and _settleSell() and recomputing goldOut or totalReceived against the fresh price, while preserving the user's original minGoldOut or minTotalReceived as a floor and introducing a complementary maxGoldOut or maxTotalReceived cap captured at request time.

• Consider adding a symmetric release path that decrements the same three per-user counters when a request ends without settlement, parameterized by the original request's createdAt and the value to release.

• Consider lowering the upper bound on the confidence-ratio setter to a value that preserves the gate's intended function, a ceiling somewhere between five hundred and two thousand basis points keeps room for legitimate operational tuning while preventing the gate from being effectively disabled.

3. TEST APPROACH AND METHODOLODY

Halborn conducted a combination of manual code review and automated security testing to balance efficiency, timeliness, practicality, and accuracy within the scope of this assessment. While manual testing is crucial for identifying flaws in logic, processes, and implementation, automated testing enhances coverage of smart contracts and quickly detects deviations from established security best practices.

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

• Research into the platform's architecture, purpose and use.

• Manual code review and walkthrough of smart contracts to identify any logical issues.

• Comprehensive assessment of the safety and usage of critical Solidity variables and functions within scope that could lead to arithmetic-related vulnerabilities.

• Local testing using custom scripts (Foundry).

• Fork testing against main networks (Foundry).

• Static security analysis of scoped contracts, and imported functions (Slither).