Introduction
We express our gratitude to the Credbull team for the collaborative engagement that enabled the execution of this Smart Contract Security Assessment.
Credbull is an integrated Decentralized Finance (DeFi) platform giving investors access to private credit as an asset class. The audit particularly focuses on Credbull CBL token.
Document | |
|---|---|
| Name | Smart Contract Code Review and Security Analysis Report for Credbull |
| Audited By | Stepan Chekhovskoi, Andy Cho |
| Approved By | Ataberk Yavuzer |
| Website | https://credbull.io→ |
| Changelog | 16/10/2024 - Preliminary Report |
| 17/10/2024 - Final Report | |
| Platform | Arbitrum |
| Language | Solidity |
| Tags | ERC-20 |
| Methodology | https://hackenio.cc/sc_methodology→ |
Document
- Name
- Smart Contract Code Review and Security Analysis Report for Credbull
- Audited By
- Stepan Chekhovskoi, Andy Cho
- Approved By
- Ataberk Yavuzer
- Website
- https://credbull.io→
- Changelog
- 16/10/2024 - Preliminary Report
- 17/10/2024 - Final Report
- Platform
- Arbitrum
- Language
- Solidity
- Tags
- ERC-20
- Methodology
- https://hackenio.cc/sc_methodology→
Review Scope | |
|---|---|
| Repository | https://github.com/credbull/credbull-defi→ |
| Commit | 0792b613b5253440ccd181f5614403ec6382da81 |
Review Scope
- Commit
- 0792b613b5253440ccd181f5614403ec6382da81
Audit Summary
The system users should acknowledge all the risks summed up in the risks section of the report
Documentation quality
The contract code is covered with comprehensive documentation and NatSpec comments.
The repository provides instructions for development environment setup.
Code quality
The code is clean and effectively utilizes standard ERC-20 token implementation with some extensions.
Test coverage
Code coverage of the project is 100% (branch coverage).
The code is covered with tests.
System Overview
The CBL contract is ERC20-compliant token with additional features listed below.
Permit: Allows approvals to be made via signatures, following the EIP-712 standard.
Mintable: Authorized users are allowed to mint additional tokens.
Burnable: Tokens can be burned, reducing the total supply.
Capped Supply: The total supply of tokens is capped.
The token properties are set as follows.
Name: Credbull
Symbol: CBL
Max Supply: Set at the moment of deployment
Privileged roles
The specified minters are allowed to mint tokens until the supply cap is not exceeded.
Potential Risks
Centralized Minting to a Single Address: The project concentrates minting tokens in a single address, raising the risk of fund mismanagement or theft, especially if key storage security is compromised.
Single Points of Failure and Control: The project is fully or partially centralized, introducing single points of failure and control. This centralization can lead to vulnerabilities in decision-making and operational processes, making the system more susceptible to targeted attacks or manipulation.
Burned Tokens Remint Possibility: The token implements Burnable and Capped Supply extensions, allowing authorized minters to remint tokens that were burned. Such behavior might be unclear to users, as burning usually means a decrease in circulating supply. In this case, it may not function this way, especially if minters are not centralized (for example, mint ability delegated to another smart contract).
ERC-20 Permit Functionality: The permit functionality poses a risk of race conditions between authorizations with the same nonce. The permit implementation requires all authorizations to be applied sequentially, with each nonce increased by one.
Findings
Code ― | Title | Status | Severity | |
|---|---|---|---|---|
| F-2024-6659 | Floating Pragma | accepted | Observation |
Appendix 1. Definitions
Severities
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. |
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.
Potential Risks
The "Potential Risks" section identifies issues that are not direct security vulnerabilities but could still affect the project’s performance, reliability, or user trust. These risks arise from design choices, architectural decisions, or operational practices that, while not immediately exploitable, may lead to problems under certain conditions. Additionally, potential risks can impact the quality of the audit itself, as they may involve external factors or components beyond the scope of the audit, leading to incomplete assessments or oversight of key areas. This section aims to provide a broader perspective on factors that could affect the project's long-term security, functionality, and the comprehensiveness of the audit findings.
Appendix 2. Scope
The scope of the project includes the following smart contracts from the provided repository:
Scope Details | |
|---|---|
| Repository | https://github.com/credbull/credbull-defi→ |
| Commit | 0792b613b5253440ccd181f5614403ec6382da81 |
| Whitepaper | https://docs.credbull.io/docs/litepaper→ |
| Requirements | packages/contracts/test/src/token/CBL_README.md |
| Technical Requirements | README.md, packages/contracts/README.md |
Scope Details
- Commit
- 0792b613b5253440ccd181f5614403ec6382da81
- Whitepaper
- https://docs.credbull.io/docs/litepaper→
- Requirements
- packages/contracts/test/src/token/CBL_README.md
- Technical Requirements
- README.md, packages/contracts/README.md
Assets in Scope
Appendix 3. Additional Valuables
Additional Recommendations
The smart contracts in the scope of this audit could benefit from the introduction of automatic emergency actions for critical activities, such as unauthorized operations like ownership changes or proxy upgrades, as well as unexpected fund manipulations, including large withdrawals or minting events. Adding such mechanisms would enable the protocol to react automatically to unusual activity, ensuring that the contract remains secure and functions as intended.
To improve functionality, these emergency actions could be designed to trigger under specific conditions, such as:
Detecting changes to ownership or critical permissions.
Monitoring large or unexpected transactions and minting events.
Pausing operations when irregularities are identified.
These enhancements would provide an added layer of security, making the contract more robust and better equipped to handle unexpected situations while maintaining smooth operations.