Kroco

Smart Contract Audit Report

Audit Summary

Kroco Audit Report Kroco 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 Kroco contract at 0x46944A120eb088b994F650d87944436d14b6a0B4 on the Binance Smart Chain Mainnet.

Audit Findings

Please ensure trust in the team prior to investing as they have notable control in the ecosystem.
Date: April 18th, 2022.

Finding #1 - Kroco - 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 - Kroco - Informational

Description: Several state variables can never be modified, but are not declared constant.
_decimals, _name, _symbol, _tTotal, numTokensSellToAddToLiquidity
Recommendation: These state variables should be declared constant for additional gas savings on each call.

Finding #3 - Kroco - Informational

Description: The following code in the _transfer() function is redundant as the isSniper and purchaseOrSale local variables are not used in the contract.
function _transfer(
...
bool isSniper = false;
if (antiSniping_failsafe && launchedAt + 3 >= block.number) {
  isSniper = true;
}
...
bool purchaseOrSale = false;
if (to == KrocoUniswapV2Pair) {
  //It's a sell, boys!
  purchaseOrSale = true;
}
Recommendation: The above code can be removed from the contract for additional gas savings on each call.

Finding #4 - Kroco - Informational

Description: The contract contains two setter functions for the numTokensSellToAddToLiquidity state variable.
function setnumTokensSellToAddToLiquidity(uint256 newValue) external onlyOwner {
numTokensSellToAddToLiquidity = newValue * 10**8;
}
...
  function setNumTokensell(uint value ) public onlyOwner {
numTokensSellToAddToLiquidity = value;
}
Recommendation: One of the above functions can be removed to reduce contract size and deployment costs.

Contract Overview

  • The total supply of the token is set to 100 billion $Kroc [100,000,000,000].
  • 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, there are 125 total token holders. The token allocation is as follows:
    • 57.62% of the total supply belongs to the owner.
    • 15% of the total supply is split evenly between three unverified contracts.
    • 5% of the total supply is stored in a token vesting contract and will unlock on July 5th, 2022.
    • The next three EOAs own a cumulative 15% of the total supply.

  • The contract enforces a maximum transaction amount (determined by the owner) which imposes a limit to the number of tokens that can be transferred in a single transaction.
  • The contract enforces a maximum wallet amount that prevents a transfer from occurring if the recipient's token balance will exceed the limit number of tokens (determined by the owner) after the transfer occurs.
  • There is a Tax fee, Liquidity fee, Marketing fee, and Buyback fee on all transfers where neither the sender nor the recipient is excluded from fees. A separate fee structure can be set by the team to apply different fee percentages depending on whether the transfer is a buy or a sell.
  • The tokens collected through the Tax fee are removed from the circulating supply; This serves as a frictionless fee redistribution that automatically benefits all token holders at the time of each transaction.
  • The Liquidity fee charged during transfers is 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 tokens in (determined by the owner) the contract address has been reached.
    • The contract is not currently performing an automatic liquidity add.
    • The caller is not initiating a buy transaction via Pancakeswap.
  • 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 0x00 address.
  • The tokens collected through the Marketing fee and Buyback fee are swapped for BNB and sent to the team's Marketing wallet and Buyback wallet respectively.
  • The contract utilizes the SafeMath library to protect against overflows/underflows.
  • The contract complies with the BEP-20 token standard.
Ownership Controls:
  • The owner can modify the Tax fee, Liquidity fee, Marketing fee, and Buyback fee to any percentages as long as the total fee percentage combined does not exceed 25% for both fee structures.
  • The owner can exclude and include accounts from transfer fees and reward distribution.
  • The owner can enable/disable the maximum transaction amount restriction at any time.
  • The owner can set the maximum transaction amount and maximum wallet amount to any values at any time.
  • The owner can exclude and include accounts from the maximum transaction amount and maximum wallet amount restrictions.
  • 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 update the team's Marketing wallet and Buyback wallet at any time.
  • The owner can withdraw all of the BNB from the contract at any time.
  • The multiSig address set by the team also has access to the above ownership-restricted functions.

Audit Results

Vulnerability CategoryNotesResult
Arbitrary Storage WriteN/APASS
Arbitrary JumpN/APASS
Centralization of ControlThe owner can set the maximum transaction amount and maximum wallet amount to any values at any time.WARNING
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
ReentrancyN/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

 + [Lib] Address 
    - [Int] isContract
    - [Int] sendValue #
    - [Int] functionCall #
    - [Int] functionCall #
    - [Int] functionCallWithValue #
    - [Int] functionCallWithValue #
    - [Int] functionStaticCall
    - [Int] functionStaticCall
    - [Int] functionDelegateCall #
    - [Int] functionDelegateCall #
    - [Prv] _verifyCallResult

 + [Int] IERC20 
    - [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

 +  Ownable (Context)
    - [Pub]  #
    - [Pub] owner
    - [Pub] renounceOwnership #
       - modifiers: onlyOwner
    - [Pub] transferOwnership #
       - modifiers: onlyOwner
    - [Pub] setMultisigOwnership #
       - modifiers: onlyOwner
    - [Pub] geUnlockTime
    - [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] MINIMUM_LIQUIDITY
    - [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 #

 +  Kroco (Context, IERC20, Ownable)
    - [Pub]  #
    - [Pub] name
    - [Pub] symbol
    - [Pub] decimals
    - [Pub] totalSupply
    - [Pub] setMaxWalletAmount #
       - modifiers: onlyOwner
    - [Int] launch #
    - [Int] launched
    - [Pub] manualLaunchOverride #
       - modifiers: onlyOwner
    - [Pub] setAntiSnipeFailsafe #
    - [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] setIsExcludedFromTXLimit #
       - modifiers: onlyOwner
    - [Pub] isExcludedFromTXLimit
    - [Pub] excludeFromFee #
       - modifiers: onlyOwner
    - [Pub] includeInFee #
       - modifiers: onlyOwner
    - [Prv] setBuyFees #
    - [Prv] setSellFees #
    - [Ext] setMaxTxPercent #
       - modifiers: onlyOwner
    - [Ext] setnumTokensSellToAddToLiquidity #
       - modifiers: onlyOwner
    - [Pub] setSwapAndLiquifyEnabled #
       - modifiers: onlyOwner
    - [Ext]  ($)
    - [Prv] _reflectFee #
    - [Prv] _getValues
    - [Prv] _getTValues
    - [Prv] _getRValues
    - [Prv] _getRate
    - [Prv] _getCurrentSupply
    - [Prv] _takeLiquidity #
    - [Prv] calculateTaxFee
    - [Prv] calculateLiquidityFee
    - [Ext] setMarketingAddr #
       - modifiers: onlyOwner
    - [Pub] setBuybackWallet #
       - modifiers: onlyOwner
    - [Pub] getMarketingAddr
    - [Prv] removeAllFee #
    - [Prv] restoreAllFee #
    - [Pub] isExcludedFromFee
    - [Prv] _approve #
    - [Pub] enableAntiwhale #
       - modifiers: onlyOwner
    - [Prv] _transfer #
    - [Prv] swapAndLiquify #
       - modifiers: lockTheSwap
    - [Prv] swapTokensForEth #
    - [Prv] addLiquidity #
    - [Prv] sendETHToMarketing #
    - [Prv] sendETHToBuyback #
    - [Pub] setSellFee #
       - modifiers: onlyOwner
    - [Pub] setBuyFees #
       - modifiers: onlyOwner
    - [Pub] setExcludedMaxWallet #
       - modifiers: onlyOwner
    - [Pub] isExcludedFromMaxWallet
    - [Prv] _tokenTransfer #
    - [Pub] setNumTokensell #
       - modifiers: onlyOwner
    - [Prv] _transferStandard #
    - [Prv] _transferToExcluded #
    - [Prv] _transferFromExcluded #
    - [Ext] emergencyWithdraw #
       - modifiers: onlyOwner

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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.