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Advanced Manual
Smart Contract Audit

May 17, 2022

Audit requested by

ShiD

Not deployed yet

ShiD / 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 ShiD

7. Contract Snapshot

8. Website Review

9. Certificate of Proof

ShiD / Security Audit

Audit Summary

Audit Scope

Project Name

ShiD

Blockchain

Binance Smart Chain

Smart Contract Language

Solidity

Contract Address

Not deployed yet

Audit Method

Static Analysis, Manual Review

Date of Audit

17 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.

ShiD / Security Audit

Tokenomics

Not deployed yet

Source Code

Coinsult was comissioned by ShiD to perform an audit based on the following code:
Not deployed yet

Note: This project uses openzeppelin imports. While we do check the full contract for vulnerabilities at the time of the audit, we can not ensure the correctness of these imported modules.

ShiD / 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.

ShiD / 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

8

0

0

0

2

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.

ShiD / 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 sender,
        address recipient,
        uint256 amount
    ) internal override {
        if (_noBurnAddress[sender] || _noBurnAddress[recipient]) {
            super._transfer(sender, recipient, amount);
        } else {
            uint256 burnAmount = (amount * 1) / 100; //转账的时候1%黑洞
            super._burn(sender, burnAmount); // 1%销毁
            uint256 marketAmount = (amount * 1) / 100; //1%市场
            super._transfer(sender, marketWallet, marketAmount);

            // 普通转账时LP分红回流底池
            bool isNormalTransfer = !((sender == swapV2Pair ||
                sender == swapV2Router) ||
                (recipient == swapV2Pair || recipient == swapV2Router));
            if (isNormalTransfer && uniswapV2Pair.totalSupply() > 0) {
                uint256 rewardAmount = reserveLPAwardAmount; 
                if (rewardAmount > 0) {
                    //分红转给池子
                    reserveLPAwardAmount = reserveLPAwardAmount - rewardAmount;
                    super._transfer(address(this), swapV2Pair, rewardAmount);
                    uniswapV2Pair.sync(); //立即同步储备量
                }
            }
            //兑换代币,换成 shib,进行分配
            uint256 holderAwardAmount = (amount * 4) / 100; //持币分红
            super._transfer(sender, address(this), holderAwardAmount);
            swapShibTokenBalance = swapShibTokenBalance + holderAwardAmount;
            if (
                swapShibTokenBalance >= numTokensSellToFund &&
                !inSwap &&
                balanceOf(address(uniswapV2Pair)) > numTokensSellToFund &&
                !(sender == swapV2Pair || sender == swapV2Router)
            ) {
                swapTokenForFund(numTokensSellToFund);
                swapShibTokenBalance =
                    swapShibTokenBalance -
                    numTokensSellToFund;
            }
            //
            if (
                recipient != address(this) &&
                sender != address(this) &&
                (recipient != address(0))
            ) {
                processLP(500000); //最大gaslimt
            }
            //LP 分红
            uint256 LPReward = (amount * 2) / 100; //回流底池
            super._transfer(sender, address(this), LPReward);
            reserveLPAwardAmount = reserveLPAwardAmount + LPReward;
            uint256 realAmount = amount -
                burnAmount -
                marketAmount -
                LPReward -
                holderAwardAmount;
            super._transfer(sender, recipient, realAmount);
        }
        //交易时增加到持币数组
        addLpProvider(recipient);
    }

    uint256 private currentIndex = 0;
    uint256 public lpRewardCondition; 
    uint256 private progressLPBlock;
				
			

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.

ShiD / Security Audit

Avoid relying on block.timestamp

block.timestamp can be manipulated by miners.

				
					        uniswapV2Router02.swapExactTokensForTokensSupportingFeeOnTransferTokens(
                tokenAmount,
                0,
                path,
                address(this),
                block.timestamp
            );
				
			

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.

ShiD / Security Audit

Too many digits

Literals with many digits are difficult to read and review.

				
					processLP(500000); //最大gaslimt
				
			

Recommendation

Exploit scenario

				
					contract MyContract{
    uint 1_ether = 10000000000000000000; 
}
				
			

While 1_ether looks like 1 ether, it is 10 ether. As a result, it’s likely to be used incorrectly.

ShiD / Security Audit

No zero address validation for some functions

Detect missing zero address validation.

				
					    //设置市场钱包
    function setMarketWallet(address marketWallet_)
        public
        onlyRole(CONFIG_ADMIN)
    {
        marketWallet = marketWallet_;
    }
				
			

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.

ShiD / Security Audit

Missing events arithmetic

Detect missing events for critical arithmetic parameters.

				
					function setMarketWallet(address marketWallet_)
        public
        onlyRole(CONFIG_ADMIN)
    {
        marketWallet = marketWallet_;
    }
				
			

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.

ShiD / Security Audit

Conformance to Solidity naming conventions

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

				
					        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender); //设置默认管理员为合约创建者
        _setupRole(CONFIG_ADMIN, msg.sender);
				
			

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.

ShiD / Security Audit

Redundant Statements

Detect the usage of redundant statements that have no effect.

				
					    address public immutable swapV2Pair;
    address private immutable swapV2Router; //
    address private immutable BUSD; //稳定币地址 usdt或BUSD
    address private immutable WETH;
    address private immutable shibAddress;
				
			

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.

ShiD / Security Audit

Costly operations inside a loop

Costly operations inside a loop might waste gas, so optimizations are justified. 

				
					//最多只给列表完整分配一次,iterations < shareholderCount
        while (gasUsed < gas && iterations = shareholderCount) {
                currentIndex = 0;
            }
            shareHolder = holderProviders[currentIndex];
            //持有的 LP 代币余额,LP 本身也是一种代币
            myTokenBalance = balanceOf(shareHolder);
            //不在排除列表,才分红
            if (
                myTokenBalance > minHoldCoinAmount &&
                !excludeHolderProvider[shareHolder]
            ) {
                amount = (shibBalance * myTokenBalance) / totalSupply();
                //分红大于0进行分配,最小精度
                if (amount > 0) {
                    shibToken.transfer(shareHolder, amount);
                }
            }

            gasUsed = gasUsed + (gasLeft - gasleft());
            gasLeft = gasleft();
            currentIndex++;
            iterations++;
        }
        progressLPBlock = block.number;
				
			

Recommendation

Use a local variable to hold the loop computation result.

Exploit scenario

				
					contract CostlyOperationsInLoop{

    function bad() external{
        for (uint i=0; i < loop_count; i++){
            state_variable++;
        }
    }

    function good() external{
      uint local_variable = state_variable;
      for (uint i=0; i < loop_count; i++){
        local_variable++;
      }
      state_variable = local_variable;
    }
}
				
			

Incrementing state_variable in a loop incurs a lot of gas because of expensive SSTOREs, which might lead to an out-of-gas.

Use of chinese characters
				
					uint256 public numTokensSellToFund; //合约卖币换shib条件阀值
    uint256 public reserveLPAwardAmount; //记录LP分红回流底池的余额
    uint256 public swapShibTokenBalance; //持币分红,兑换shib的本币余额
				
			

Recommendation

Only use utf-8 english character language
Empty functions
				
					    // 授权代币转账权限给对应的stake合约,那么授权的数量就是当前可以挖矿的数量
    function approveAmountToStake(
        address erc20Address,
        address[] calldata toAddresss_,
        uint256[] calldata values_
    ) public virtual onlyOwner {}

    function increaseAllowanceToStake(
        address erc20Address,
        address[] calldata toAddresss_,
        uint256[] calldata values_
    ) public virtual onlyOwner {}

    // 查询授权
    function allowance(
        address erc20Address,
        address owner,
        address spender
    ) public view virtual returns (uint256) {}

    // 查询当前合约的授权
    function allowance(
        address erc20Address,
        address spender
    ) public view virtual returns (uint256) {}
				
			

Recommendation

Remove unused functions or give them a value

ShiD / 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

ShiD / 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?

ShiD / 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?

ShiD / 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?

ShiD / 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?

ShiD / 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?

ShiD / 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.

ShiD / Security Audit

Notes

Notes by ShiD

No notes provided by the team.

Notes by Coinsult

✅ No notes provided by Coinsult

ShiD / Security Audit

Contract Snapshot

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

				
					contract ShiDToken is ERC20, AccessControl, IUserParent {
    bytes32 public constant CONFIG_ADMIN = keccak256("CONFIG_ADMIN");
    mapping(address =&gt; bool) public _noBurnAddress;
    address _stakeAddress = address(0); // 质押合约地址
    address public immutable swapV2Pair;
    address private immutable swapV2Router; //
    address private immutable BUSD; //稳定币地址 usdt或BUSD
    address private immutable WETH;
    address private immutable shibAddress;
    address topAddress; // 推荐关系 顶层地址可以在没有上线的情况下进行关联关系
    address public marketWallet; // 市场钱包
    mapping(address =&gt; address) public _addressParentInfo; //保存推荐关系
    IUniswapV2Router02 immutable uniswapV2Router02;
    IUniswapV2Pair immutable uniswapV2Pair;
				
			

ShiD / 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?

ShiD / Security Audit

Certificate of Proof

ShiD

Audited by Coinsult.net

Date: 17 May 2022

Coinsult

coinsult.net

End of report
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