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  • [SCA] Gunzilla / Payment Plan / Feb2024
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GUNZ

Audit name:

[SCA] Gunzilla / Payment Plan / Feb2024

Date:

Mar 6, 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 Gunzilla team for the collaborative engagement that enabled the execution of this Smart Contract Security Assessment.

titlecontent
PlatformEVM
LanguageSolidity
TagsVesting
Timeline16/02/2024 - 26/02/2024
Methodologyhttps://hackenio.cc/sc_methodology→

    Review Scope

    Repositoryhttps://github.com/Gunzilla-Games/gun-vesting-contracts→
    Initial Commitfd9649c8a7e7c5bdaeb0bf4ecf0a36048785f7c9
    Remediation Commit308d34a350b388c1d3b3177dbeb03d24c4bc7a64

    Audit Summary

    Total10/10
    Security Score

    10/10

    Test Coverage

    100%

    Code Quality Score

    10/10

    Documentation Quality Score

    10/10

    9Total Findings
    8Resolved
    1Accepted
    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 Gunzilla
    Audited ByNiccolò Pozzolini, Kornel Światłowski
    Approved ByPrzemyslaw Swiatowiec
    Website-
    Changelog20/02/2024 - Preliminary Report; 26/02/2024 - Second Review

    • Document

      Name
      Smart Contract Code Review and Security Analysis Report for Gunzilla
      Audited By
      Niccolò Pozzolini, Kornel Światłowski
      Approved By
      Przemyslaw Swiatowiec
      Website
      -
      Changelog
      20/02/2024 - Preliminary Report; 26/02/2024 - Second Review

    System Overview

    Gunzilla PaymentPlan is a modular vesting contract. A base vesting contract, GunPaymentPlan, is inherited by extension contracts that define the vesting behavior. One of such contracts is GunLinearPaymentPlan which implements a linear vesting.

    Privileged roles

    • The owner can pause/unpause the protocol, vest tokens to users, and add payment plans on the GunLinearPaymentPlan contract.

    Executive Summary

    Documentation quality

    The total Documentation Quality score is 10 out of 10.

    • Functional requirements are complete.

    • Technical description is provided.

    Code quality

    The total Code Quality score is 10 out of 10.

    • The development environment is configured.

    Test coverage

    Code coverage of the project is 100% (branch coverage).

    • Deployment and basic user interactions are covered with tests.

    Security score

    Upon auditing, the code was found to contain 0 critical, 0 high, 0 medium, and 1 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 10. This score reflects the combined evaluation of documentation, code quality, test coverage, and security aspects of the project.

    Risks

    The vesting cliff concept in this project diverges from the standard. The initial allocation (namely initiallyUnlockedPercent) is released at the beginning of the vesting process, instead of after the cliff period.

    The withdraw functionality can be paused by the admin.

    The Solidity version 0.8.20 employs the recently introduced PUSH0 opcode in the Shanghai EVM. This opcode might not be universally supported across all blockchain networks and Layer 2 solutions. Thus, as a result, it might not be possible to deploy the solution with a version equal to or higher than 0.8.20 on some blockchains.

    Findings

    Code
    ―
    Title
    Status
    Severity
    F-2024-0882Use of transfer or send instead of call to send native assets
    accepted

    Low
    F-2024-0944Missing variable cache can lead to increased Gas usage in the withdrawableAmount function
    fixed

    Observation
    F-2024-0943Missing access control of the receive function
    fixed

    Observation
    F-2024-0942Potential code readability improvement by using long numeric literal
    fixed

    Observation
    F-2024-0941Floating pragma
    fixed

    Observation
    F-2024-0937Code duplication
    fixed

    Observation
    F-2024-0883Gas inefficiency due to missing usage of Solidity custom errors
    fixed

    Observation
    F-2024-0881Some public functions should be declared as external
    fixed

    Observation
    F-2024-0880Missing two-step ownership transfer process
    fixed

    Observation
    1-9 of 9 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
    GunLinearPaymentPlan.sol - contracts/GunLinearPaymentPlan.sol
    abstract
    GunPaymentPlan.sol - contracts/abstract/GunPaymentPlan.sol

    Disclaimer