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Advanced Manual
Smart Contract Audit

July 26, 2022

Audit requested by

Metaverse MSN

0xaf51951df5782fa6eb529c173b10a973e4871f92

Metaverse MSN / Security Audit

Table of Contents

1. Audit Summary

1.1 Audit scope

1.2 Tokenomics

1.3 Source Code

2. Disclaimer

3. Global Overview

3.1 Informational issues

3.2 Low-risk issues

3.3 Medium-risk issues

3.4 High-risk issues

4. Vulnerabilities Findings

5. Contract Privileges

5.1 Maximum Fee Limit Check

5.2 Contract Pausability Check

5.3 Max Transaction Amount Check

5.4 Exclude From Fees Check

5.5 Ability to Mint Check

5.6 Ability to Blacklist Check

5.7 Owner Privileges Check

6. Notes

6.1 Notes by Coinsult

6.2 Notes by Metaverse MSN

7. Contract Snapshot

8. Website Review

9. Certificate of Proof

Metaverse MSN / Security Audit

Audit Summary

Audit Scope

Project Name

Metaverse MSN

Website

Blockchain

Binance Smart Chain

Smart Contract Language

Solidity

Contract Address

0xaf51951df5782fa6eb529c173b10a973e4871f92

Audit Method

Static Analysis, Manual Review

Date of Audit

26 July 2022

This audit report has been prepared by Coinsult’s experts at the request of the client. In this audit, the results of the static analysis and the manual code review will be presented. The purpose of the audit is to see if the functions work as intended, and to identify potential security issues within the smart contract.

The information in this report should be used to understand the risks associated with the smart contract. This report can be used as a guide for the development team on how the contract could possibly be improved by remediating the issues that were identified.

Metaverse MSN / Security Audit

Tokenomics

Rank Address Quantity (Token) Percentage
1  0x4863a1c6500d297090d9dc351f37a4918d768fe7 1,054.920451257390099246 21.0984%
2 0x0de661868475d6f6da6861f1fa72dfd0b5eba33c 300 6.0000%
3 0xe07bb15eba6462e589f3bc3d1b3f6c25fca9c36c 200 4.0000%
4 0x5780f00117272d30cb8a13ae7b81c05975839fe0 186.728644013897455895 3.7346%
5 0xb68cfa1a68ead8cbe9300f2fc0859568d5287cf2 86.70557907935153395 1.7341%

Source Code

Coinsult was comissioned by Metaverse MSN to perform an audit based on the following code:
https://bscscan.com/address/0xaf51951df5782fa6eb529c173b10a973e4871f92#code

Metaverse MSN / Security Audit

Disclaimer

This audit report has been prepared by Coinsult’s experts at the request of the client. In this audit, the results of the static analysis and the manual code review will be presented. The purpose of the audit is to see if the functions work as intended, and to identify potential security issues within the smart contract.

The information in this report should be used to understand the risks associated with the smart contract. This report can be used as a guide for the development team on how the contract could possibly be improved by remediating the issues that were identified.

Coinsult is not responsible if a project turns out to be a scam, rug-pull or honeypot. We only provide a detailed analysis for your own research.

Coinsult is not responsible for any financial losses. Nothing in this contract audit is financial advice, please do your own research.

The information provided in this audit is for informational purposes only and should not be considered investment advice. Coinsult does not endorse, recommend, support or suggest to invest in any project. 

Coinsult can not be held responsible for when a project turns out to be a rug-pull, honeypot or scam.

Metaverse MSN / Security Audit

Global Overview

Manual Code Review

In this audit report we will highlight the following issues:

Vulnerability Level

Total

Pending

Acknowledged

Resolved

0

0

0

0

6

0

0

0

0

0

0

0

0

0

0

0

Privilege Overview

Coinsult checked the following privileges:

Contract Privilege

Description

Owner can mint?

Owner can blacklist?

Owner can set fees > 25%?

Owner can exclude from fees?

Owner can pause trading?

Owner can set Max TX amount?

More owner priviliges are listed later in the report.

Metaverse MSN / Security Audit

Avoid relying on block.timestamp

block.timestamp can be manipulated by miners.

				
					function Launch(uint256 _time) public onlyOwner {
        require(!isLaunch);
        isLaunch = true;
        if(_time == 0){
            startTime = block.timestamp;
        }else{
            startTime = _time;
        }
    }
				
			

Recommendation

Do not use block.timestampnow or blockhash as a source of randomness

Exploit scenario

				
					contract Game {

    uint reward_determining_number;

    function guessing() external{
      reward_determining_number = uint256(block.blockhash(10000)) % 10;
    }
}
				
			

Eve is a miner. Eve calls guessing and re-orders the block containing the transaction. As a result, Eve wins the game.

Metaverse MSN / Security Audit

Functions that send Ether to arbitrary destinations

Unprotected call to a function sending Ether to an arbitrary address.

				
					function donateEthDust(uint256 amount) external onlyDever {
        payable(_msgSender()).transfer(amount);
    }
				
			

Recommendation

Ensure that an arbitrary user cannot withdraw unauthorized funds.

Exploit scenario

				
					contract ArbitrarySend{
    address destination;
    function setDestination(){
        destination = msg.sender;
    }

    function withdraw() public{
        destination.transfer(this.balance);
    }
}
				
			

Bob calls setDestination and withdraw. As a result he withdraws the contract’s balance.

Metaverse MSN / Security Audit

Unchecked transfer

The return value of an external transfer/transferFrom call is not checked.

				
					function withdraw() public {
        uint256 fistBalance = fist.balanceOf(address(this));
        if (fistBalance > 0) {
            fist.transfer(address(token), fistBalance);
        }
        uint256 tokenBalance = token.balanceOf(address(this));
        if (tokenBalance > 0) {
            token.transfer(address(token), tokenBalance);
        }
    }
				
			

Recommendation

Use SafeERC20, or ensure that the transfer/transferFrom return value is checked.

Exploit scenario

				
					contract Token {
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
}
contract MyBank{  
    mapping(address => uint) balances;
    Token token;
    function deposit(uint amount) public{
        token.transferFrom(msg.sender, address(this), amount);
        balances[msg.sender] += amount;
    }
}
				
			

Several tokens do not revert in case of failure and return false. If one of these tokens is used in MyBankdeposit will not revert if the transfer fails, and an attacker can call deposit for free..

Metaverse MSN / Security Audit

Divide before multiply

Solidity integer division might truncate. As a result, performing multiplication before division can sometimes avoid loss of precision.

				
					function _takeInviterFee(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        address cur;
        address reciver;
        if (ammPairs[sender]) {
            cur = recipient;
        } else {
            cur = sender;
        }
        uint256 rate;
        uint256 rAmount = tAmount.div(1000).mul(10);
				
			

Recommendation

Consider ordering multiplication before division.

Exploit scenario

				
					contract A {
	function f(uint n) public {
        coins = (oldSupply / n) * interest;
    }
}
				
			

If n is greater than oldSupplycoins will be zero. For example, with oldSupply = 5; n = 10, interest = 2, coins will be zero. If (oldSupply * interest / n) was used, coins would have been 1. In general, it’s usually a good idea to re-arrange arithmetic to perform multiplication before division, unless the limit of a smaller type makes this dangerous.

Metaverse MSN / Security Audit

Missing events arithmetic

Detect missing events for critical arithmetic parameters.

				
					function setlpDivThres(uint256 _thres) public onlyOwner {
        lpTokenDivThres = _thres;
    }
				
			

Recommendation

Emit an event for critical parameter changes.

Exploit scenario

				
					contract C {

  modifier onlyAdmin {
    if (msg.sender != owner) throw;
    _;
  }

  function updateOwner(address newOwner) onlyAdmin external {
    owner = newOwner;
  }
}
				
			

updateOwner() has no event, so it is difficult to track off-chain changes in the buy price.

Metaverse MSN / Security Audit

Redundant Statements

Detect the usage of redundant statements that have no effect.

				
					function _msgData() internal view virtual returns (bytes memory) {
        this;
        // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
				
			

Recommendation

Remove redundant statements if they congest code but offer no value.

Exploit scenario

				
					contract RedundantStatementsContract {

    constructor() public {
        uint; // Elementary Type Name
        bool; // Elementary Type Name
        RedundantStatementsContract; // Identifier
    }

    function test() public returns (uint) {
        uint; // Elementary Type Name
        assert; // Identifier
        test; // Identifier
        return 777;
    }
}
				
			

Each commented line references types/identifiers, but performs no action with them, so no code will be generated for such statements and they can be removed.

Metaverse MSN / Security Audit

Contract Privileges

Maximum Fee Limit Check

Coinsult tests if the owner of the smart contract can set the transfer, buy or sell fee to 25% or more. It is bad practice to set the fees to 25% or more, because owners can prevent healthy trading or even stop trading when the fees are set too high. 

Type of fee

Description

Transfer fee

Buy fee

Sell fee

Type of fee

Description

Max transfer fee

Max buy fee

Max sell fee

Metaverse MSN / Security Audit

Contract Pausability Check

Coinsult tests if the owner of the smart contract has the ability to pause the contract. If this is the case, users can no longer interact with the smart contract; users can no longer trade the token.

Privilege Check

Description

Can owner pause the contract?

Metaverse MSN / Security Audit

Max Transaction Amount Check

Coinsult tests if the owner of the smart contract can set the maximum amount of a transaction. If the transaction exceeds this limit, the transaction will revert. Owners could prevent normal transactions to take place if they abuse this function.

Privilege Check

Description

Can owner set max tx amount?

Metaverse MSN / Security Audit

Exclude From Fees Check

Coinsult tests if the owner of the smart contract can exclude addresses from paying tax fees. If the owner of the smart contract can exclude from fees, they could set high tax fees and exclude themselves from fees and benefit from 0% trading fees. However, some smart contracts require this function to exclude routers, dex, cex or other contracts / wallets from fees.

Privilege Check

Description

Can owner exclude from fees?

Metaverse MSN / Security Audit

Ability To Mint Check

Coinsult tests if the owner of the smart contract can mint new tokens. If the contract contains a mint function, we refer to the token’s total supply as non-fixed, allowing the token owner to “mint” more tokens whenever they want.

A mint function in the smart contract allows minting tokens at a later stage. A method to disable minting can also be added to stop the minting process irreversibly.

Minting tokens is done by sending a transaction that creates new tokens inside of the token smart contract. With the help of the smart contract function, an unlimited number of tokens can be created without spending additional energy or money.

Privilege Check

Description

Can owner mint?

Metaverse MSN / Security Audit

Ability To Blacklist Check

Coinsult tests if the owner of the smart contract can blacklist accounts from interacting with the smart contract. Blacklisting methods allow the contract owner to enter wallet addresses which are not allowed to interact with the smart contract. 

This method can be abused by token owners to prevent certain / all holders from trading the token. However, blacklists might be good for tokens that want to rule out certain addresses from interacting with a smart contract.

Privilege Check

Description

Can owner blacklist?

Metaverse MSN / Security Audit

Other Owner Privileges Check

Coinsult lists all important contract methods which the owner can interact with.

⚠ Owner can set minimum wallet value for inviter fee

⚠ Owner can reset list of  inviter addresses

Metaverse MSN / Security Audit

Notes

Notes by Metaverse MSN

No notes provided by the team.

Notes by Coinsult

✅ No notes provided by Coinsult

Metaverse MSN / Security Audit

Contract Snapshot

This is how the constructor of the contract looked at the time of auditing the smart contract.

				
					contract MSN is ERC20 {
    using SafeMath for uint256;
    
    IUniswapV2Router02 public uniswapV2Router;
    IUniswapV2Pair public  uniswapV2Pair;
    address _tokenOwner;
    address private _destroyAddress = address(0x000000000000000000000000000000000000dEaD);
    address private fundAddress = address(0x05532F432956fe9ea53cD65B14194717003c2079);
    address private ecoAddress = address(0xda0cbCC99628121c0Df3294f75b3B25642228003);
    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => bool) private _isDelivers;
    mapping(address => bool) public _isBot;
    mapping(address => address) public inviter;
    mapping(address => bool) public inviterBlack;
    mapping(address => uint256) public inviterLockTime;
    uint256 public inviterRequireLockTime;
    uint256 public thresRefAmount;
    bool public isLaunch = false;
    uint256 public startTime;
    bool public swapAndLiquifyEnabled = true;
    bool private swapping = false;
				
			

Metaverse MSN / Security Audit

Website Review

Coinsult checks the website completely manually and looks for visual, technical and textual errors. We also look at the security, speed and accessibility of the website. In short, a complete check to see if the website meets the current standard of the web development industry. 

Type of check

Description

Mobile friendly?

Contains jQuery errors?

Is SSL secured?

Contains spelling errors?

Metaverse MSN / Security Audit

Certificate of Proof

Metaverse MSN

Audited by Coinsult.net

Date: 26 July 2022

Coinsult

coinsult.net

End of report
Smart Contract Audit

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