Audit name:
[SCA][Re-Audit] Crypto Real Estate | ERC20 | Sep2023
Date:
Sep 22, 2023
Table of Content
Introduction
We express our gratitude to the CRE team for the collaborative engagement that enabled the execution of this Smart Contract Security Assessment.
Crypto Real Estate is a company bridging the gap between the real estate industry and cryptocurrencies through our mobile app and real world business ventures including a crypto hotel and cafes.
| title | content |
|---|---|
| Platform | EVM |
| Language | Solidity |
| Tags | ERC20 |
| Timeline | 05/05/2023 - 25/09/2023 |
| Methodology | https://hackenio.cc/sc_methodology→ |
Review Scope | |
|---|---|
| Repository | https://dev.azure.com/blockstars/Solidity→ |
| Commit | 2de82e38f61602c2c79e85627f415740ef8b7ddf |
Review Scope
- Commit
- 2de82e38f61602c2c79e85627f415740ef8b7ddf
Audit Summary
10/10
0%
10/10
10/10
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 CRE |
| Audited By | Hacken |
| Website | https://www.creproject.com/→ |
| Changelog | 12/05/2023 - Initial Review |
| 23/05/2023 - Second Review | |
| 25/09/2023 - Third Review |
Document
- Name
- Smart Contract Code Review and Security Analysis Report for CRE
- Audited By
- Hacken
- Website
- https://www.creproject.com/→
- Changelog
- 12/05/2023 - Initial Review
- 23/05/2023 - Second Review
- 25/09/2023 - Third Review
System Overview
CryptoRealEstate is an ERC-20 token that mints all initial supplies to a given address provided during contract creation. Additional minting is not allowed. It has the following attributes:
Name: Crypto Real Estate
Symbol: CRE
Decimals: 18
Total supply: 100M tokens.
CryptoRealEstate uses OpenZeppelin Ownable contract to restrict access to critical functionalities, but transferOwnership() is not allowed. During contract creation, there is a new pair on Uniswap created - CRE/wETH. Additionally, each transfer of these tokens is taxed with up to 9 % and tax is burned. Owner of the contract can add an address to the whitelist and transferring tokens to or from the whitelisted address omits tax. There are 3 available taxes, but only one is appalled per transfer:
buyTax - up to 3%, this tax is applied when transfer is done from DEX.
sellTax - up to 9%, this tax is applied when transferring to DEX. Half of the tax is burned and the second half is saved for marketing wallet.
transferTax - up to 3%, this tax is applied when transferring to or from other addresses.
Privileged roles
The owner of the CryptoRealEstate contract can add or can remove a given address from the whitelist, change buy, sell and transfer tax, set marketing wallet address, open trading, withdraw ERC20 or native tokens from contract.
Executive Summary
Documentation quality
The total Documentation quality score is 10 out of 10.
Functional requirements are detailed.
A detailed technical description is provided in the form of extensive NatSpec comments.
Code quality
The total Code quality score is 10 out of 10.
Development environment is configured.
Code follows best practices.
Test coverage
Code coverage of the project is 0% (branch coverage).
No tests.
Security score
Upon auditing, the code was found to contain 0 critical, 0 high, 1 medium, and 7 low severity issues. Out of these, 8 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 10. This score reflects the combined evaluation of documentation, code quality, test coverage, and security aspects of the project.
Risks
If a Marketing Wallet address is a contract without the ability to withdraw native tokens, funds can be potentially locked.
Findings
Code ― | Title | Status | Severity | |
|---|---|---|---|---|
| F-2023-0613 | Requirements Violation | fixed | Medium | |
| F-2023-0620 | Contradiction - Documentation Mismatch | fixed | Low | |
| F-2023-0619 | Contradiction - Undocumented Functionality | fixed | Low | |
| F-2023-0618 | CEI Pattern Violation | fixed | Low | |
| F-2023-0617 | Missing Events | fixed | Low | |
| F-2023-0616 | Missing Zero Address Validation | fixed | Low | |
| F-2023-0615 | Unchecked Transfer | fixed | Low | |
| F-2023-0614 | Unscalable Functionality - Copy Of Well-Known Contract | fixed | Low | |
| I-2023-0128 | Style Guide Violation - Naming Conventions | fixed | Observation | |
| I-2023-0127 | Typo | fixed | Observation |
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://dev.azure.com/blockstars/Solidity→ |
| Commit | 2de82e38f61602c2c79e85627f415740ef8b7ddf |
| Whitepaper | Provided→ |
| Requirements | Provided (CRE Token.docx + CRE Token Requirements.pdf) |
| Technical Requirements | Provided (CRE Token.docx + CRE Token Requirements.pdf) |
Scope Details
- Commit
- 2de82e38f61602c2c79e85627f415740ef8b7ddf
- Whitepaper
- Provided→
- Requirements
- Provided (CRE Token.docx + CRE Token Requirements.pdf)
- Technical Requirements
- Provided (CRE Token.docx + CRE Token Requirements.pdf)