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Coins & Skins

Audit name:

[SCA] Coins & Skins | ERC20 | Jan2024

Date:

Feb 11, 2024

Table of Content

→Introduction
→Audit Summary
→Document Information
→System Overview
→Executive Summary
→Risks
→Findings
→Appendix 1. Severity Definitions
→Appendix 2. Scope
→Disclaimer

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Introduction

We express our gratitude to the Coins & Skins team for the collaborative engagement that enabled the execution of this Smart Contract Security Assessment.

COINS & SKINS is an ERC-20 tokens.

titlecontent
PlatformEthereum
LanguageSolidity
TagsERC-20
Timeline23/01/2024 - 25/01/2024
Methodologyhttps://hackenio.cc/sc_methodology→

    Review Scope

    Repositoryhttps://github.com/holdex/SKINS-token→
    Commit1df37236811ccd60c645bec1ec2a5b86c66e813d

    Audit Summary

    Total9.6/10
    Security Score

    10/10

    Test Coverage

    100%

    Code Quality Score

    8/10

    Documentation Quality Score

    10/10

    3Total Findings
    0Resolved
    3Accepted
    0Mitigated

    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

    NameSmart Contract Code Review and Security Analysis Report for Coins & Skins
    Audited ByMaksym Fedorenko
    Approved ByAtaberk Yavuzer
    Websitehttps://coinsandskins.com/→
    Changelog26/01/2024 - Preliminary Report
    29/01/2024 - Final Report

    • Document

      Name
      Smart Contract Code Review and Security Analysis Report for Coins & Skins
      Audited By
      Maksym Fedorenko
      Approved By
      Ataberk Yavuzer
      Website
      https://coinsandskins.com/→
      Changelog
      26/01/2024 - Preliminary Report
      29/01/2024 - Final Report

    System Overview

    Coins & Skins is an ERC-20 token contract.

    It has the following attributes:

    • Deployment target chain: Ethereum.

    • Contract Type: ERC-20.

    • Total token supply: 800,000,000.

    • Burnable: no.

    • Mintable: no (fixed supply).

    The contract includes the next libraries and contracts:

    Value — is an abstract contract. It contains a modifier named nonZA that ensures a function is not called with the zero address as the sender. It declares a custom error NonZeroAddress to handle such cases.

    SafeMath —  is a custom abstract contract, which provides functions for performing arithmetic operations with safety checks to prevent overflows and underflows.

    Votes — is the contract with the votes delegation logic (out of the audit scope).

    Nonces — is a custom contract designed to manage and validate nonces for signed messages related to the vote delegation.

    Privileged roles

    • There is no explicit concept of an owner.

    • The deployer, being the entity that deploys the contract to the blockchain, has control over the contract deployment process but does not have special privileges or control over the contract's behavior after deployment unless explicitly specified within the contract's functions or state variables.

    Executive Summary

    Documentation quality

    The total Documentation Quality score is 10 out of 10.

    • Functional token requirements are clear.

    • Technical token description is provided within the Readme file.

    • NatSpec covers the code and is detailed.

    Code quality

    The total Code Quality score is 8 out of 10.

    • The code has redundant code blocks with unused functions and variables.

    • The code mixes uint and uint256 type declarations.

    Test coverage

    Code coverage of the project is 100%.

    Security score

    Upon auditing, the code was found to contain 0 critical, 0 high, 0 medium, and 0 low severity issues, 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 9.6. This score reflects the combined evaluation of documentation, code quality, test coverage, and security aspects of the project.

    Scoring Methodologyarrow right

    Risks

    The functionality related to the Votes.sol smart contract is out of scope and should not be utilized in production.

    Findings

    F-2024-0629The Code Mixes uint And uint256 Type Declaration
    Status
    accepted
    Severity

    Observation
    F-2024-0628EIP-20 Standard Violation
    Status
    accepted
    Severity

    Observation
    F-2024-0596Redundant Code Block
    Status
    accepted
    Severity

    Observation
    Code
    ―
    Title
    Status
    Severity
    F-2024-0629The Code Mixes uint And uint256 Type Declaration
    accepted

    Observation
    F-2024-0628EIP-20 Standard Violation
    accepted

    Observation
    F-2024-0596Redundant Code Block
    accepted

    Observation
    1-3 of 3 findings

    Identify vulnerabilities in your smart contracts.

    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:

    Contracts in Scope

    contracts
    Skins.sol - contracts › Skins.sol
    utils
    Nonces.sol - contracts › utils › Nonces.sol
    Value.sol - contracts › utils › Value.sol
    SafeMath.sol - contracts › utils › SafeMath.sol

    Disclaimer