Prepared by:
HALBORN
Last Updated 06/20/2025
Date of Engagement: June 11th, 2025 - June 13th, 2025
100% of all REPORTED Findings have been addressed
All findings
7
Critical
0
High
0
Medium
0
Low
0
Informational
7
The Horizen Foundation engaged Halborn to conduct a security assessment on their smart contracts on June 11th, 2025 to June 13th, 2025. The security assessment was scoped to the smart contracts and scripts provided to the Halborn team.
The Horizen Foundation prepared a migration from all funds of the ZEND and EON blockchains to an ERC20 smart contract on the BASE blockchain and the reviewed scope provided balances dump scripts as well as the BASE smart contracts used to load and claim the migrated balances.
The team at Halborn was provided 3 days for the engagement and assigned a security engineer to evaluate the security of the smart contract. The security engineer is a blockchain and smart-contract security expert with advanced penetration testing, smart-contract hacking, and deep knowledge of multiple blockchain protocols.
The purpose of the assessment is to:
Ensure that smart contract and scripts functions operate as intended.
Identify potential security issues with the smart contracts or scripts.
In summary, Halborn identified some minor improvements to reduce the likelihood and impact of risks, which have been completely addressed by the Horizen Foundation team. The main ones were the following:
Implement two step ownership transfer process.
Catch signature bad formats before reverting with a generic error.
Halborn performed a combination of manual review of the code and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of the smart contract assessment. While manual testing is recommended to uncover flaws in logic, process, and implementation; automated testing techniques help enhance coverage of smart contracts 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.
Smart contract manual code review and walkthrough to identify any logic issue.
Thorough assessment of safety and usage of critical Move variables and functions in scope that could lead to arithmetic related vulnerabilities.
Manual testing by custom scripts.
| EXPLOITABILITY METRIC () | METRIC VALUE | NUMERICAL VALUE |
|---|---|---|
| Attack Origin (AO) | Arbitrary (AO:A) Specific (AO:S) | 1 0.2 |
| Attack Cost (AC) | Low (AC:L) Medium (AC:M) High (AC:H) | 1 0.67 0.33 |
| Attack Complexity (AX) | Low (AX:L) Medium (AX:M) High (AX:H) | 1 0.67 0.33 |
| IMPACT METRIC () | METRIC VALUE | NUMERICAL VALUE |
|---|---|---|
| Confidentiality (C) | None (C:N) Low (C:L) Medium (C:M) High (C:H) Critical (C:C) | 0 0.25 0.5 0.75 1 |
| Integrity (I) | None (I:N) Low (I:L) Medium (I:M) High (I:H) Critical (I:C) | 0 0.25 0.5 0.75 1 |
| Availability (A) | None (A:N) Low (A:L) Medium (A:M) High (A:H) Critical (A:C) | 0 0.25 0.5 0.75 1 |
| Deposit (D) | None (D:N) Low (D:L) Medium (D:M) High (D:H) Critical (D:C) | 0 0.25 0.5 0.75 1 |
| Yield (Y) | None (Y:N) Low (Y:L) Medium (Y:M) High (Y:H) Critical (Y:C) | 0 0.25 0.5 0.75 1 |
| SEVERITY COEFFICIENT () | COEFFICIENT VALUE | NUMERICAL VALUE |
|---|---|---|
| Reversibility () | None (R:N) Partial (R:P) Full (R:F) | 1 0.5 0.25 |
| Scope () | Changed (S:C) Unchanged (S:U) | 1.25 1 |
| Severity | Score Value Range |
|---|---|
| Critical | 9 - 10 |
| High | 7 - 8.9 |
| Medium | 4.5 - 6.9 |
| Low | 2 - 4.4 |
| Informational | 0 - 1.9 |
Critical
0
High
0
Medium
0
Low
0
Informational
7
| Security analysis | Risk level | Remediation Date |
|---|---|---|
| EON Dump Allows Silent Address Re-use | Informational | Acknowledged - 06/12/2025 |
| No Two-Step Ownership Transfer | Informational | Acknowledged - 06/13/2025 |
| Locked Unclaimed Stake In Vaults | Informational | Acknowledged - 06/13/2025 |
| Unnecessary Satoshi-Level Rounding | Informational | Acknowledged - 06/13/2025 |
| Unsorted eon_vault_results Array Used | Informational | Acknowledged - 06/13/2025 |
| Signature Zero r And s Not Explicitly Rejected | Informational | Solved - 06/13/2025 |
| Signature v-Byte Range Not Asserted | Informational | Solved - 06/13/2025 |
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Halborn strongly recommends conducting a follow-up assessment of the project either within six months or immediately following any material changes to the codebase, whichever comes first. This approach is crucial for maintaining the project’s integrity and addressing potential vulnerabilities introduced by code modifications.
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Horizen Migration - Code Review
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