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Advanced Manual
Smart Contract Audit

July 15, 2022

Audit requested by

Web3 Capital

0xdbf23b67027c1a5fd242fd1d61b2846543459854

Web3 Capital / 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 Web3 Capital

7. Contract Snapshot

8. Website Review

9. Certificate of Proof

Web3 Capital / Security Audit

Audit Summary

Audit Scope

Project Name

Web3 Capital

Blockchain

Binance Smart Chain

Smart Contract Language

Solidity

Contract Address

0xdbf23b67027c1a5fd242fd1d61b2846543459854

Audit Method

Static Analysis, Manual Review

Date of Audit

15 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.

Web3 Capital / Security Audit

Tokenomics

Rank Address Quantity (Token) Percentage
1 0x2779f1b8daf02d94ddda4fdbc90fc7dea00305c0 1,000,000,000,000,000 100.0000%

Source Code

Coinsult was comissioned by Web3 Capital to perform an audit based on the following code:
https://bscscan.com/address/0xdbf23b67027c1a5fd242fd1d61b2846543459854#code

Web3 Capital / 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.

Web3 Capital / 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

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.

Web3 Capital / 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 returns (bool) {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");
        bool buy = false;
        bool sell = false;
        bool other = false;
        if (lpPairs[from]) {
            buy = true;
        } else if (lpPairs[to]) {
            sell = true;
        } else {
            other = true;
        }
        if(_hasLimits(from, to)) {
            if(!tradingEnabled) {
                revert("Trading not yet enabled!");
            }
            if(buy || sell){
                if (!_isExcludedFromLimits[from] && !_isExcludedFromLimits[to]) {
                    require(amount <= _maxTxAmount, "Transfer amount exceeds the maxTxAmount.");
                }
            }
            if(to != address(dexRouter) && !sell) {
                if (!_isExcludedFromLimits[to]) {
                    require(balanceOf(to) + amount = swapThreshold) {
                    uint256 swapAmt = swapAmount;
                    if(piContractSwapsEnabled) { swapAmt = (balanceOf(lpPair) * piSwapPercent) / masterTaxDivisor; }
                    if(contractTokenBalance >= swapAmt) { contractTokenBalance = swapAmt; }
                    contractSwap(contractTokenBalance);
                }
            }
        }
        return _finalizeTransfer(from, to, amount, takeFee, buy, sell, other);
    }
				
			

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.

Web3 Capital / Security Audit

Avoid relying on block.timestamp

block.timestamp can be manipulated by miners.

				
					            if (timeSinceLastPair != 0) {
                require(block.timestamp - timeSinceLastPair > 3 days, "Cannot set a new pair this week!");
            }
				
			

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.

Web3 Capital / Security Audit

Too many digits

Literals with many digits are difficult to read and review.

				
					    uint256 reflectorGas = 300000;
				
			

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.

Web3 Capital / Security Audit

No zero address validation for some functions

Detect missing zero address validation.

				
					    function setWallets(address payable marketing) external onlyOwner {
        _taxWallets.marketing = payable(marketing);
    }
				
			

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.

Web3 Capital / Security Audit

Functions that send Ether to arbitrary destinations

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

				
					        if(ratios.marketing > 0){
            (success,) = _taxWallets.marketing.call{value: marketingBalance, gas: 30000}("");
        }
				
			

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.

Web3 Capital / Security Audit

Missing events arithmetic

Detect missing events for critical arithmetic parameters.

				
					   function setWallets(address payable marketing) external onlyOwner {
        _taxWallets.marketing = payable(marketing);
    }

    function setMaxTxPercent(uint256 percent, uint256 divisor) external onlyOwner {
        require((_tTotal * percent) / divisor >= (_tTotal / 1000), "Max Transaction amt must be above 0.1% of total supply.");
        _maxTxAmount = (_tTotal * percent) / divisor;
    }

				
			

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.

Web3 Capital / Security Audit

Boolean equality

Detects the comparison to boolean constants.

				
					function setLpPair(address pair, bool enabled) external onlyOwner {
        if (enabled == false) {
            lpPairs[pair] = false;
            antiSnipe.setLpPair(pair, false);
        } else {
            if (timeSinceLastPair != 0) {
                require(block.timestamp - timeSinceLastPair > 3 days, "Cannot set a new pair this week!");
            }
            lpPairs[pair] = true;
            timeSinceLastPair = block.timestamp;
            antiSnipe.setLpPair(pair, true);
        }
    }
				
			

Recommendation

Remove the equality to the boolean constant.

Exploit scenario

				
					contract A {
	function f(bool x) public {
		// ...
        if (x == true) { // bad!
           // ...
        }
		// ...
	}
}
				
			

Boolean constants can be used directly and do not need to be compare to true or false.

Web3 Capital / Security Audit

Costly operations inside a loop

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

				
					    function multiSendTokens(address[] memory accounts, uint256[] memory amounts) external onlyOwner {
        require(accounts.length == amounts.length, "Lengths do not match.");
        for (uint8 i = 0; i = amounts[i]);
            _finalizeTransfer(msg.sender, accounts[i], amounts[i]*10**_decimals, false, false, false, true);
        }
    }
				
			

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.

approveContractContingency can be abused
				
					    function approveContractContingency() public onlyOwner returns (bool) {
        _approve(address(this), address(dexRouter), type(uint256).max);
        return true;
    }
				
			

Recommendation

The owner can change variable ‘dexRouter’, and can set the address to a malicious contract in order to withdraw all of the tokens from the contract. This function should be removed and the contract should only grant approval for the exact amount of tokens being used when performing automatic liquidity.

Web3 Capital / 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

Web3 Capital / 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?

Web3 Capital / 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?

Web3 Capital / 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?

Web3 Capital / 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?

Web3 Capital / 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?

Web3 Capital / Security Audit

Other Owner Privileges Check

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

⚠ Owner can set max wallet size

⚠ Owner can set max price impact

 

 

Web3 Capital / Security Audit

Notes

Notes by Web3 Capital

No notes provided by the team.

Notes by Coinsult

✅ No notes provided by Coinsult

Web3 Capital / Security Audit

Contract Snapshot

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

				
					contract Web3Capital is IERC20 {
    // Ownership moved to in-contract for customizability.
    address private _owner;

    mapping (address =&gt; uint256) _tOwned;
    mapping (address =&gt; bool) lpPairs;
    uint256 private timeSinceLastPair = 0;
    mapping (address =&gt; mapping (address =&gt; uint256)) _allowances;
    mapping (address =&gt; bool) private _isExcludedFromProtection;
    mapping (address =&gt; bool) private _isExcludedFromFees;
    mapping (address =&gt; bool) private _isExcludedFromLimits;
    mapping (address =&gt; bool) private _isExcludedFromDividends;
    mapping (address =&gt; bool) private _liquidityHolders;

    mapping (address =&gt; bool) private presaleAddresses;
    bool private allowedPresaleExclusion = true;

    uint256 constant private startingSupply = 1_000_000_000_000_000;

    string constant private _name = "Web3 Capital";
    string constant private _symbol = "WEB";
    uint8 constant private _decimals = 9;

    uint256 constant private _tTotal = startingSupply * (10 ** _decimals);

    struct Fees {
        uint16 buyFee;
        uint16 sellFee;
        uint16 transferFee;
    }

    struct Ratios {
        uint16 rewards;
        uint16 liquidity;
        uint16 marketing;
        uint16 burn;
        uint16 total;
    }

    Fees public _taxRates = Fees({
        buyFee: 1500,
        sellFee: 1500,
        transferFee: 1500
        });

    Ratios public _ratios = Ratios({
        rewards: 500,
        liquidity: 0,
        marketing: 500,
        burn: 500,
        total: 1500
        });
				
			

Web3 Capital / 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?

Web3 Capital / Security Audit

Certificate of Proof

Web3 Capital

Audited by Coinsult.net

Date: 15 July 2022

Coinsult

coinsult.net

End of report
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