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Advanced Manual
Smart Contract Audit

May 25, 2022

Audit requested by

Chainbook

0x0332BFE76242dc3D3A82bFBad044bF274ff82D85

Chainbook / 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 Chainbook

7. Contract Snapshot

8. Website Review

9. Certificate of Proof

Chainbook / Security Audit

Audit Summary

Audit Scope

Project Name

Chainbook

Blockchain

Binance Smart Chain

Smart Contract Language

Solidity

Contract Address

0x0332BFE76242dc3D3A82bFBad044bF274ff82D85

Audit Method

Static Analysis, Manual Review

Date of Audit

25 May 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.

Chainbook / Security Audit

Tokenomics

Rank Address Quantity (Token) Percentage
1 Null Address: 0x000…dEaD 5,000,000,000 50.0000%
2 0xd5e2932c858882cd086b400a5fabe8f87422a448 3,600,000,000 36.0000%
3 0x4fddc2d48f293ca949a8fbe7e3941ca2dc7a6849 600,000,000 6.0000%
4 0x568db913f1e2ea2fb788220552f49954ec3b3e85 500,000,000 5.0000%
5 0xdf3bcfedc368142c3477d4f0a44d80844d8d7450 300,000,000 3.0000%

Source Code

Coinsult was comissioned by Chainbook to perform an audit based on the following code:
https://bscscan.com/address/0x0332bfe76242dc3d3a82bfbad044bf274ff82d85#code

Chainbook / 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.

Chainbook / 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.

Chainbook / Security Audit

Contract contains Reentrancy vulnerabilities

Additional information: This combination increases risk of malicious intent. While it may be justified by some complex mechanics (e.g. rebase, reflections, buyback). 

More information: Slither

				
					function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal override {

        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(!_isBlacklisted[from], 'Blacklisted address');

        if(amount == 0) {
            super._transfer(from, to, 0);
            return;
        }

        // No adding liquidity before launched
        if (!liquidityLaunched) {
            if (to == uniswapV2Pair) {
                liquidityLaunched = true;
                // high tax ends in x blocks
                lastSnipeTaxBlock = block.number + snipeBlocks;
            }
        }

        //antibot block
        if (from != address(_PresaleAddress)) {
            if(liquidityLaunched && block.number = swapTokensAtAmount;

        if( canSwap &&
            !swapping &&
            !automatedMarketMakerPairs[from] &&
            from != owner() &&
            to != owner()
        ) {
            swapping = true;

            uint256 tokenAmount = balanceOf(address(this));

            uint256 tokenAmountForUseful = tokenAmount.mul(UsefulShare).div(AllShare);
            uint256 tokenAmountOther = tokenAmount.sub(tokenAmountForUseful);
            uint256 tokenAmountLP = tokenAmountOther.div(2);
            uint256 tokenAmountBurn = tokenAmountOther.sub(tokenAmountLP);

            if(tokenAmountBurn>0){
                uint256 burnAmount = balanceOf(address(deadWallet));
                if (burnAmount < burnEndAmount) {
                    super._transfer(address(this),deadWallet,tokenAmountBurn);
                    tokenAmountBurn = 0;
                }
            }
            
            swapAndLiquify(tokenAmountLP+tokenAmountBurn);
            swapTokensForEth(tokenAmountForUseful);

            uint256 BNBAmount = address(this).balance;

            uint256 BNBAmountForDev = BNBAmount.div(2);
            uint256 BNBAmountForMkt = BNBAmount.sub(BNBAmountForDev);

            payable(_AppWalletAddress).transfer(BNBAmountForDev);
            payable(_FoudWalletAddress).transfer(BNBAmountForMkt);
            
            swapping = false;
        }

        bool takeFee = !swapping;

        // if any account belongs to _isExcludedFromFee account then remove the fee
        if(_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            takeFee = false;
        }

        if (takeFee) {
            if (from == address(uniswapV2Pair) || to == address(uniswapV2Pair)) {
                uint256 fees = amount.mul(AllFee).div(100);
                amount = amount.sub(fees);
                super._transfer(from, address(this), fees);
            }
        }

        super._transfer(from, to, amount);
    }
				
			

Recommendation

Apply the check-effects-interactions pattern.

Exploit scenario

				
					    function withdrawBalance(){
        // send userBalance[msg.sender] Ether to msg.sender
        // if mgs.sender is a contract, it will call its fallback function
        if( ! (msg.sender.call.value(userBalance[msg.sender])() ) ){
            throw;
        }
        userBalance[msg.sender] = 0;
    }
				
			
Bob uses the re-entrancy bug to call withdrawBalance two times, and withdraw more than its initial deposit to the contract.

Chainbook / Security Audit

No zero address validation for some functions

Detect missing zero address validation.

				
					function setDevWallet(address payable wallet) external onlyOwner{
        _AppWalletAddress = wallet;
    }
				
			

Recommendation

Check that the new address is not zero.

Exploit scenario

				
					contract C {

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

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

Bob calls updateOwner without specifying the newOwner, soBob loses ownership of the contract.

Chainbook / Security Audit

Functions that send Ether to arbitrary destinations

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

				
					function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        // approve token transfer to cover all possible scenarios
        _approve(address(this), address(uniswapV2Router), tokenAmount);

        // add the liquidity
        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            address(0),
            block.timestamp
        );
    }
				
			

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.

Chainbook / Security Audit

Missing events arithmetic

Detect missing events for critical arithmetic parameters.

				
					function setFee(
        uint256 _MktFee,
        uint256 _DevFee,
        uint256 _LpFee,
        uint256 _BurnFee,
        uint256 _UsefulShare,
        uint256 _OtherShare
    ) public onlyOwner {
        MktFee = _MktFee;
        DevFee = _DevFee;
        LpFee = _LpFee;
        BurnFee = _BurnFee;

        UsefulShare = _UsefulShare;
        OtherShare = _OtherShare;

        AllFee = MktFee.add(DevFee).add(LpFee).add(BurnFee);
        AllShare = UsefulShare.add(OtherShare);
    }
				
			

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.

Chainbook / Security Audit

Conformance to Solidity naming conventions

Allow _ at the beginning of the mixed_case match for private variables and unused parameters.

				
					uint256 public AllFee;
				
			

Recommendation

Follow the Solidity naming convention.

Rule exceptions

  • Allow constant variable name/symbol/decimals to be lowercase (ERC20).
  • Allow _ at the beginning of the mixed_case match for private variables and unused parameters.

Chainbook / Security Audit

Redundant Statements

Detect the usage of redundant statements that have no effect.

				
					function _msgData() internal view virtual returns (bytes calldata) {
        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.

Chainbook / 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

Chainbook / 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?

Chainbook / 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?

Chainbook / 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?

Chainbook / 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?

Chainbook / 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?

Chainbook / Security Audit

Other Owner Privileges Check

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

✅ No other important owner privileges to mention.

Chainbook / Security Audit

Notes

Notes by Chainbook

No notes provided by the team.

Notes by Coinsult

✅ No notes provided by Coinsult

Chainbook / Security Audit

Contract Snapshot

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

				
					contract ChainBook is ERC20, Ownable {
    using SafeMath for uint256;

    IUniswapV2Router02 public uniswapV2Router;
    address public  uniswapV2Pair;

    bool private swapping;

    address public deadWallet = 0x000000000000000000000000000000000000dEaD;
    address public _AppWalletAddress = 0xdf3bcfEdc368142c3477D4F0A44d80844D8D7450;
    address public _FoudWalletAddress = 0x568db913f1e2EA2Fb788220552F49954Ec3B3e85;

    uint256 public totalSupply_ = 100 * (10**8) * (10**18);

    uint256 public swapTokensAtAmount;

    uint256 public burnEndAmount;
				
			

Chainbook / 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?

Chainbook / Security Audit

Certificate of Proof

Chainbook

Audited by Coinsult.net

Date: 25 May 2022

Coinsult

coinsult.net

End of report
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