Audit name:
[SCA] Tokeny | ERC20 | Dec2022
Date:
Mar 28, 2023
Table of Content
Introduction
We express our gratitude to the Tokeny team for the collaborative engagement that enabled the execution of this Smart Contract Security Assessment.
Tokeny Solutions allows companies operating in private markets to benefit from using blockchain technology, while maintaining compliance and control.
| title | content |
|---|---|
| Platform | EVM |
| Language | Solidity |
| Tags | ERC20, ERC734, ERC735, ERC3643 |
| Timeline | 01/12/2022 - 30/03/2023 |
| Methodology | https://hackenio.cc/sc_methodology→ |
Review Scope | |
|---|---|
| Repository | https://github.com/TokenySolutions/T-REX/tree/hacken-corrections→ |
| Commit | e32436b93927c5efb4454e8baf14d904f7f14c45 |
Review Scope
- Commit
- e32436b93927c5efb4454e8baf14d904f7f14c45
Audit Summary
10/10
83.64%
9/10
8/10
The system users should acknowledge all the risks summed up in the risks section of the report
Document Information
This report may contain confidential information about IT systems and the intellectual property of the Customer, as well as information about potential vulnerabilities and methods of their exploitation.
The report can be disclosed publicly after prior consent by another Party. Any subsequent publication of this report shall be without mandatory consent.
Document | |
|---|---|
| Name | Smart Contract Code Review and Security Analysis Report for Tokeny |
| Audited By | Hacken |
| Website | https://tokeny.com/→ |
| Changelog | 06/12/2022 - Initial Review |
| 30/12/2022 - Second Review | |
| 30/03/2023 - Third Review |
Document
- Name
- Smart Contract Code Review and Security Analysis Report for Tokeny
- Audited By
- Hacken
- Website
- https://tokeny.com/→
- Changelog
- 06/12/2022 - Initial Review
- 30/12/2022 - Second Review
- 30/03/2023 - Third Review
System Overview
TREX is an infrastructure to manage ERC20-based permissioned tokens by means of a decentralized validator. It is based on 4 pillars:
ONCHAINID →: external on-chain identity management system.
Validation Certificates: referred to as claims. These are ERC734 and ERC735 based certificates, emitted by trusted third parties and signed on-chain. Each of them is linked to a single ONCHAINID.
Compliance Rules: set of rules for a particular token, according to the issuer’s requirements and any additional feature. These are checked and managed by a transfer manager role.
Eligibility Verification System (EVS): validator that filters the P2P transactions of permissioned tokens, according to the claims each peer holds and the compliance rules of the tokens. These rules are linked to the identities of transaction receivers and the global distribution of tokens at a certain time.
Privileged roles
The owner and the agent roles have huge control over the contract’s properties, including pausing, unpausing, minting, burning, forced transfers, adding/removing agents/compliances, changing the implementation, and so on.
Executive Summary
Documentation quality
The total Documentation quality score is 8 out of 10.
White paper is provided.
Functional requirements are clearly defined.
Technical description is provided, but not for all contracts (i.e. TREXFactory and proxy approach).
NatSpec implementation in Smart Contracts.
Code quality
The total Code quality score is 9 out of 10.
The code duplicates commonly known contracts instead of reusing them (ERC20).
The development environment is configured.
Test coverage
Code coverage of the project is 83.64% (branch coverage).
Deployment and basic user interactions are covered with tests.
Negative cases coverage is present.
Interactions by several users are not tested thoroughly.
Security score
Upon auditing, the code was found to contain 2 critical, 4 high, 4 medium, and 12 low severity issues. Out of these, 18 issues have been addressed and resolved, leading to a Security score of 10 out of 10.
All identified issues are detailed in the “Findings” section of this report.
Summary
The comprehensive audit of the customer's smart contract yields an overall score of 9. This score reflects the combined evaluation of documentation, code quality, test coverage, and security aspects of the project.
Risks
The repository contains out-of-scope contracts, the secureness and reliability of which could not be verified by the current audit.
Findings
Code ― | Title | Status | Severity | |
|---|---|---|---|---|
| F-2023-0817 | Access Control Violation | fixed | Critical | |
| F-2023-0816 | Access Control Violation / Denial of Service | fixed | Critical | |
| F-2023-0821 | Standard Violation | mitigated | High | |
| F-2023-0820 | Unverifiable Logic | fixed | High | |
| F-2023-0819 | Non-Finalized Code | fixed | High | |
| F-2023-0818 | Requirements Violation / Missing Validation | fixed | High | |
| F-2023-0825 | Missing Validation | fixed | Medium | |
| F-2023-0824 | Unscalable Functionality: Copy of Well-Known Contracts | mitigated | Medium | |
| F-2023-0823 | Check Effects Interaction Violation | fixed | Medium | |
| F-2023-0822 | Denial of Service (DoS) | fixed | Medium |
Appendix 1. Severity Definitions
When auditing smart contracts, Hacken is using a risk-based approach that considers Likelihood, Impact, Exploitability and Complexity metrics to evaluate findings and score severities.
Reference on how risk scoring is done is available through the repository in our Github organization:
Severity | Description |
|---|---|
Critical | Critical vulnerabilities are usually straightforward to exploit and can lead to the loss of user funds or contract state manipulation. |
High | High vulnerabilities are usually harder to exploit, requiring specific conditions, or have a more limited scope, but can still lead to the loss of user funds or contract state manipulation. |
Medium | Medium vulnerabilities are usually limited to state manipulations and, in most cases, cannot lead to asset loss. Contradictions and requirements violations. Major deviations from best practices are also in this category. |
Low | Major deviations from best practices or major Gas inefficiency. These issues will not have a significant impact on code execution, do not affect security score but can affect code quality score. |
Severity
- Critical
Description
- Critical vulnerabilities are usually straightforward to exploit and can lead to the loss of user funds or contract state manipulation.
Severity
- High
Description
- High vulnerabilities are usually harder to exploit, requiring specific conditions, or have a more limited scope, but can still lead to the loss of user funds or contract state manipulation.
Severity
- Medium
Description
- Medium vulnerabilities are usually limited to state manipulations and, in most cases, cannot lead to asset loss. Contradictions and requirements violations. Major deviations from best practices are also in this category.
Severity
- Low
Description
- Major deviations from best practices or major Gas inefficiency. These issues will not have a significant impact on code execution, do not affect security score but can affect code quality score.
Appendix 2. Scope
The scope of the project includes the following smart contracts from the provided repository:
Scope Details | |
|---|---|
| Repository | https://github.com/TokenySolutions/T-REX/tree/hacken-corrections→ |
| Commit | e32436b93927c5efb4454e8baf14d904f7f14c45 |
| Whitepaper | Provided→ |
| Requirements | Provided→ |
| Technical Requirements | Provided→ |