Smart Contract Audit Report

Audit Summary

MuNFTBEP20  Audit Report MuNFTBEP20 is a new BEP-20 token on the Binance Smart Chain that is an automatic liquidity providing protocol that pays out static rewards to holders.

For this audit, we reviewed the project team's MuNFTBEP20 contract at 0x15DD9a1AD0B3edCcDeeFBD23AB6b8DE5cfa81272 on the Binance Smart Chain Mainnet.

Audit Findings

Please ensure trust in the team prior to investing as they have substantial control in the ecosystem.
Date: March 9th, 2022.
Updated: April 7th, 2022 to reflect the contract's new mainnet address.

Finding #1 - MuNFTBEP20 - Low

Description: The owner can use the lock() function to temporarily set ownership to address(0). Ownership is restored after the duration of time determined by the owner has passed and they use the unlock() function.
Risk/Impact: The unlock function has the potential to be used after ownership has been set to address(0), which will restore ownership to the original owner that initially created the ownership lock. This can be used in a nefarious way by the project team to restore ownership and change fee structures.
Recommendation: We recommend that the unlock function be modified to set the previous owner variable equal to address(0) at the end of the unlock function to prevent it from being used more than once per lock.
Resolution: The team has not yet addressed this issue.

Finding #2 - MuNFTBEP20 - Informational

Description: Several functions are declared public, but are never called internally.
name, symbol, decimals, totalSupply, transfer, allowance, approve, transferFrom, increaseAllowance, decreaseAllowance, isExcludedFromReward, totalFees, deliver, reflectionFromToken, excludeFromReward, excludeFromFee, includeInFee, setSwapAndLiquifyEnabled, setSwapActivity, isExcludedFromFee
Recommendation: These functions should be declared external for additional gas savings on each call.

Finding #3 - MuNFTBEP20 - Informational

Description: Several state variables can never be modified, but are not declared constant.
_decimals, _name, _symbol, _tTotal, ownerAddress
Recommendation: These state variables can be declared constant for additional gas savings on each reference and to reduce deployment costs.

Finding #4 - MuNFTBEP20 - Informational

Description: Although the SafeMath library is utilized, the contract is deployed with Solidity v0.8.12 which has built-in overflow checks.
Recommendation: SafeMath could be safely removed to reduce contract size and deployment costs.

Contract Overview

  • The total supply of the token is set to 2.5 million $MSS [2,500,000].
  • No mint or burn functions exist, though the circulating supply can be decreased by sending tokens to the 0x..dead address.
  • At the time of writing this report, 100% of the total supply belongs to the owner.

  • There is a Tax fee, Liquidity fee, and Marketing fee on all transfers where neither the sender nor the recipient is excluded from fees.
  • The tokens collected through the Tax fee are removed from the circulating supply; This serves as a frictionless fee redistribution which automatically benefits all token holders at the time of each transaction.
  • The remaining fees are stored in the contract address. The tokens are swapped for BNB for the purpose of funding Pancakeswap liquidity when the following conditions are met:
    • The automatic liquidity add functionality is enabled by the team.
    • The threshold number of 12,500 tokens in the contract address has been reached.
    • The contract is not currently performing an automatic liquidity add.
    • The sender is not the Pancakeswap Pair address.
  • Liquidity-adds are automatically performed by selling the tokens collected as fees, pairing the received BNB with the token, and adding it as liquidity to the BNB pair.
  • The LP tokens received through this process are sent to the owner. We recommend that the team lock these newly acquired LP tokens.
  • The tokens collected from the Marketing fee are swapped for BNB and sent to the team's Marketing wallet.
  • The contract enforces a maximum transaction amount (determined by the owner) which imposes a limit to the number of tokens that can be transferred during any given transaction.
  • As the contract is deployed with Solidity v0.8.12, it is protected from overflows/underflows.
  • The contract complies with the BEP-20 token standard.
Ownership Controls:
  • The owner can modify the Tax fee, Liquidity fee, and Marketing fee to any percentages at any time.
  • The owner can exclude and include accounts from transfer fees and reward distribution.
  • The owner can update the maximum transaction amount to any value at any time.
  • The owner can enable/disable automatic liquidity adds at any time.
  • The owner can update the threshold number of tokens needed to trigger an automatic liquidity add to any value at any time.
  • The owner can pause/unpause all transfers that involve Pancakeswap at any time.
  • The owner can update the team's Marketing wallet to any address at any time.

Audit Results

Vulnerability CategoryNotesResult
Arbitrary Jump/Storage WriteN/APASS
Centralization of Control
  • The owner can set each fee up to 100%.
  • The LP tokens generated through automatic liquidity adds are sent to the owner.
  • The team currently owns ~99% of the total supply.
    Compiler IssuesN/APASS
    Delegate Call to Untrusted ContractN/APASS
    Dependence on Predictable VariablesN/APASS
    Ether/Token TheftN/APASS
    Flash LoansN/APASS
    Front RunningN/APASS
    Improper EventsN/APASS
    Improper Authorization SchemeN/APASS
    Integer Over/UnderflowN/APASS
    Logical IssuesN/APASS
    Oracle IssuesN/APASS
    Outdated Compiler VersionN/APASS
    Race ConditionsN/APASS
    Signature IssuesN/APASS
    Unbounded LoopsN/APASS
    Unused CodeN/APASS
    Overall Contract Safety PASS

    Inheritance Chart

    Smart Contract Audit - Inheritance

    Function Graph

    Smart Contract Audit - Graph

    Functions Overview

     ($) = payable function
     # = non-constant function
     Int = Internal
     Ext = External
     Pub = Public
     + [Int] IBEP20 
        - [Ext] totalSupply
        - [Ext] balanceOf
        - [Ext] transfer #
        - [Ext] allowance
        - [Ext] approve #
        - [Ext] transferFrom #
     + [Lib] SafeMath 
        - [Int] add
        - [Int] sub
        - [Int] sub
        - [Int] mul
        - [Int] div
        - [Int] div
        - [Int] mod
        - [Int] mod
     +  Context 
        - [Int] _msgSender
        - [Int] _msgData
     + [Lib] Address 
        - [Int] isContract
        - [Int] sendValue #
        - [Int] functionCall #
        - [Int] functionCall #
        - [Int] functionCallWithValue #
        - [Int] functionCallWithValue #
        - [Prv] _functionCallWithValue #
     +  Ownable (Context)
        - [Pub]  #
        - [Pub] owner
        - [Pub] renounceOwnership #
           - modifiers: onlyOwner
        - [Pub] transferOwnership #
           - modifiers: onlyOwner
        - [Pub] getUnlockTime
        - [Pub] getTime
        - [Pub] lock #
           - modifiers: onlyOwner
        - [Pub] unlock #
     + [Int] IUniswapV2Factory 
        - [Ext] feeTo
        - [Ext] feeToSetter
        - [Ext] getPair
        - [Ext] allPairs
        - [Ext] allPairsLength
        - [Ext] createPair #
        - [Ext] setFeeTo #
        - [Ext] setFeeToSetter #
     + [Int] IUniswapV2Pair 
        - [Ext] name
        - [Ext] symbol
        - [Ext] decimals
        - [Ext] totalSupply
        - [Ext] balanceOf
        - [Ext] allowance
        - [Ext] approve #
        - [Ext] transfer #
        - [Ext] transferFrom #
        - [Ext] DOMAIN_SEPARATOR
        - [Ext] PERMIT_TYPEHASH
        - [Ext] nonces
        - [Ext] permit #
        - [Ext] factory
        - [Ext] token0
        - [Ext] token1
        - [Ext] getReserves
        - [Ext] price0CumulativeLast
        - [Ext] price1CumulativeLast
        - [Ext] kLast
        - [Ext] mint #
        - [Ext] burn #
        - [Ext] swap #
        - [Ext] skim #
        - [Ext] sync #
        - [Ext] initialize #
     + [Int] IUniswapV2Router01 
        - [Ext] factory
        - [Ext] WETH
        - [Ext] addLiquidity #
        - [Ext] addLiquidityETH ($)
        - [Ext] removeLiquidity #
        - [Ext] removeLiquidityETH #
        - [Ext] removeLiquidityWithPermit #
        - [Ext] removeLiquidityETHWithPermit #
        - [Ext] swapExactTokensForTokens #
        - [Ext] swapTokensForExactTokens #
        - [Ext] swapExactETHForTokens ($)
        - [Ext] swapTokensForExactETH #
        - [Ext] swapExactTokensForETH #
        - [Ext] swapETHForExactTokens ($)
        - [Ext] quote
        - [Ext] getAmountOut
        - [Ext] getAmountIn
        - [Ext] getAmountsOut
        - [Ext] getAmountsIn
     + [Int] IUniswapV2Router02 (IUniswapV2Router01)
        - [Ext] removeLiquidityETHSupportingFeeOnTransferTokens #
        - [Ext] removeLiquidityETHWithPermitSupportingFeeOnTransferTokens #
        - [Ext] swapExactTokensForTokensSupportingFeeOnTransferTokens #
        - [Ext] swapExactETHForTokensSupportingFeeOnTransferTokens ($)
        - [Ext] swapExactTokensForETHSupportingFeeOnTransferTokens #
     +  MuNFTBEP20 (Context, IBEP20, Ownable)
        - [Pub]  #
        - [Pub] name
        - [Pub] symbol
        - [Pub] decimals
        - [Pub] totalSupply
        - [Pub] balanceOf
        - [Pub] transfer #
        - [Pub] allowance
        - [Pub] approve #
        - [Pub] transferFrom #
        - [Pub] increaseAllowance #
        - [Pub] decreaseAllowance #
        - [Pub] isExcludedFromReward
        - [Pub] totalFees
        - [Pub] deliver #
        - [Pub] reflectionFromToken
        - [Pub] tokenFromReflection
        - [Pub] excludeFromReward #
           - modifiers: onlyOwner
        - [Ext] includeInReward #
           - modifiers: onlyOwner
        - [Prv] _transferBothExcluded #
        - [Pub] excludeFromFee #
           - modifiers: onlyOwner
        - [Pub] includeInFee #
           - modifiers: onlyOwner
        - [Ext] setFeePercent #
           - modifiers: onlyOwner
        - [Ext] setmarketingAddress #
           - modifiers: onlyOwner
        - [Ext] setMaxTxPercent #
           - modifiers: onlyOwner
        - [Pub] setSwapAndLiquifyEnabled #
           - modifiers: onlyOwner
        - [Pub] setSwapActivity #
           - modifiers: onlyOwner
        - [Ext]  ($)
        - [Prv] _reflectFee #
        - [Prv] _getValues
        - [Prv] _getTValues
        - [Prv] _getRValues
        - [Prv] _getRate
        - [Prv] _getCurrentSupply
        - [Prv] _takeLiquidity #
        - [Prv] _takeMarketing #
        - [Prv] calculateTaxFee
        - [Prv] calculateTotalFee
        - [Prv] removeAllFee #
        - [Prv] restoreAllFee #
        - [Pub] isExcludedFromFee
        - [Prv] _approve #
        - [Prv] _transfer #
        - [Prv] swapAndLiquify #
           - modifiers: lockTheSwap
        - [Prv] swapTokensForEth #
        - [Prv] addLiquidity #
        - [Prv] transferToAddressBNB #
        - [Prv] _tokenTransfer #
        - [Prv] _transferStandard #
        - [Prv] _transferToExcluded #
        - [Prv] _transferFromExcluded #

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    What is a Solidity Audit?

    Typically, a smart contract audit is a comprehensive review process designed to discover logical errors, security vulnerabilities, and optimization opportunities within code. A Solidity Audit takes this a step further by verifying economic logic to ensure the stability of smart contracts and highlighting privileged functionality to create a report that is easy to understand for developers and community members alike.

    How Do I Interpret the Findings?

    Each of our Findings will be labeled with a Severity level. We always recommend the team resolve High, Medium, and Low severity findings prior to deploying the code to the mainnet. Here is a breakdown on what each Severity level means for the project:

    • High severity indicates that the issue puts a large number of users' funds at risk and has a high probability of exploitation, or the smart contract contains serious logical issues which can prevent the code from operating as intended.
    • Medium severity issues are those which place at least some users' funds at risk and has a medium to high probability of exploitation.
    • Low severity issues have a relatively minor risk association; these issues have a low probability of occurring or may have a minimal impact.
    • Informational issues pose no immediate risk, but inform the project team of opportunities for gas optimizations and following smart contract security best practices.