Smart Contract Audit Report

Audit Summary

Vulkania Audit Report Vulkania is a new BEP-20 token that is an automatic liquidity providing protocol.

For this audit, we reviewed the project team's Vulkania contract at 0x797Bb0BeeA437D2762A755ea911C0046C1284568 on the Binance Smart Chain Mainnet.

Audit Findings

Please ensure trust in the team prior to investing as they have substantial control in the ecosystem.
Date: April 25th, 2022.
Updated: April 28th, 2022 to reflect the contract's newly deployed Mainnet address.

Finding #1 - Vulkania - Low (Resolved)

Description: _swapAndLiquify() transfers BNB from the contract to the team's fee wallets using the transfer() function instead of the call() function.
Risk/Impact: The transfer() function uses a hardcoded gas amount of 2300, meaning transactions could run out of gas as the team receives BNB.
Recommendation: Use .call.value{...}("") instead as it does not have a gas limitation.
Resolution: The team has implemented the above recommendation.

Finding #2 - Vulkania - Informational (Resolved)

Description: The _blockedTimeLimit state variable can never be modified, but is not declared constant.
Recommendation: This state variable should be declared constant for additional gas savings on each reference.
Resolution: The team has implemented the above recommendation.

Contract Overview

  • The total supply of the token is set to 40 million $VLK [40,000,000].
  • 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, 100% of the total supply belongs to the owner.

  • The owner must initially call the launch() function in order for all trading to take place on the platform. Only whitelisted accounts can participate in transfers when trading is disabled.
  • 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.
  • The contract enforces a cool-down period of 60 seconds between buys for each user within 5 minutes of the launch time.
  • Blacklisted accounts are prohibited from participating in transfers.
  • There is a Liquidity fee, Marketing fee, Dev fee, and Buyback fee on all transfers via Pancakeswap 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 user is buying or selling during the transfer.
  • Another fee structure can be set by the team if the caller is initiating a buy or a sell within the Eruption time period set by the team.
  • The fees charged during transfers are stored in the contract address. The tokens are swapped for BNB for the purpose of funding Pancakeswap liquidity and team wallets when the following conditions are met:
    • Trading is enabled.
    • The threshold number of tokens (determined by the owner) in the contract address has been reached.
    • The contract is not currently performing an automatic liquidity add.
    • Total fees are greater than 0.
    • The caller is initiating a sell transaction via Pancakeswap.
    • Neither the sender nor the recipient is the team's Liquidity, Dev, Marketing, or Buyback wallet.
  • 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 Liquidity address set by the team. We recommend that the team lock these newly acquired LP tokens.
  • The tokens collected through the Marketing fee, Dev fee, and Buyback fee are swapped for BNB and sent to the team's Marketing wallet, Dev wallet, and Buyback wallet respectively.
  • As the contract is implemented with Solidity v0.8.x it is protected from overflows/underflows.
  • The contract complies with the BEP-20 token standard.
Ownership Controls:
  • The owner can modify the Liquidity fee, Marketing fee, Dev fee, and Buyback fee for all fee structures to any percentages at any time.
  • The owner can exclude and include accounts from transfer fees.
  • The owner can add/remove accounts from the transfer blacklist within 48 hours of the launch time.
  • The owner can update the maximum transaction amount to any value at any time.
  • The owner can update the maximum wallet amount to any value at any time.
  • The owner can exclude accounts from the maximum transaction and maximum wallet restrictions 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 withdraw all of the BNB from the contract at any time.
  • The owner can set the team's Liquidity, Marketing, Dev, and Buyback wallets to any addresses at any time.
  • The owner can set the Pancakeswap Router address to any address at any time.
  • The owner can enable/disable trading at any time.
  • The owner can add/remove accounts from the pre-trading whitelist at any time.
  • The owner can set the Eruption hour start time to the current time at any time.
  • The owner can set the Eruption hour start time back to 0 at any time.
  • The owner can manually add accounts to a wallet-transfer list that will be charged fees on peer-to-peer transfers.
  • The owner can enable/disable fees on peer-to-peer transfers at any time.
  • The owner can deactivate the launch if the contract is still in its launch period.

Audit Results

Vulnerability CategoryNotesResult
Arbitrary Storage WriteN/APASS
Arbitrary JumpN/APASS
Centralization of Control
  • The owner can set each fee percentage up to 100%.
  • The LP tokens generated through automatic liquidity adds are sent to the Liquidity address set by the team.
  • The owner can enable/disable trading at any time.
Compiler IssuesN/APASS
Delegate Call to Untrusted ContractN/APASS
Dependence on Predictable VariablesN/APASS
Ether/Token TheftN/APASS
Flash LoansN/APASS
Front RunningThe Buyback system may be susceptible to front-running. The team should monitor, and if any suspicious activity is detected, lower the minimumTokensBeforeSwap threshold value.PASS
Improper EventsN/APASS
Improper Authorization SchemeN/APASS
Integer Over/UnderflowN/APASS
Logical IssuesN/APASS
Oracle IssuesN/APASS
Outdated Compiler VersionN/APASS
Race ConditionsN/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

 + [Int] IERC20 
    - [Ext] totalSupply
    - [Ext] balanceOf
    - [Ext] transfer #
    - [Ext] allowance
    - [Ext] approve #
    - [Ext] transferFrom #

 + [Int] IFactory 
    - [Ext] createPair #
    - [Ext] getPair

 + [Int] IRouter 
    - [Ext] factory
    - [Ext] WETH
    - [Ext] addLiquidityETH ($)
    - [Ext] swapExactETHForTokensSupportingFeeOnTransferTokens ($)
    - [Ext] swapExactTokensForETHSupportingFeeOnTransferTokens #

 + [Int] IERC20Metadata (IERC20)
    - [Ext] name
    - [Ext] symbol
    - [Ext] decimals

 + [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

 +  ERC20 (Context, IERC20, IERC20Metadata)
    - [Pub]  #
    - [Pub] name
    - [Pub] symbol
    - [Pub] decimals
    - [Pub] totalSupply
    - [Pub] balanceOf
    - [Pub] transfer #
    - [Pub] allowance
    - [Pub] approve #
    - [Pub] transferFrom #
    - [Pub] increaseAllowance #
    - [Pub] decreaseAllowance #
    - [Int] _transfer #
    - [Int] _mint #
    - [Int] _burn #
    - [Int] _approve #
    - [Int] _beforeTokenTransfer #

 +  Vulkania (ERC20, Ownable)
    - [Pub]  #
       - modifiers: ERC20
    - [Ext]  ($)
    - [Prv] _getNow
    - [Ext] launch #
       - modifiers: onlyOwner
    - [Ext] cancelLaunch #
       - modifiers: onlyOwner
    - [Ext] activateTrading #
       - modifiers: onlyOwner
    - [Ext] deactivateTrading #
       - modifiers: onlyOwner
    - [Ext] setEruptionHour #
       - modifiers: onlyOwner
    - [Ext] cancelEruptionHour #
       - modifiers: onlyOwner
    - [Prv] _setAutomatedMarketMakerPair #
    - [Ext] allowTradingWhenDisabled #
       - modifiers: onlyOwner
    - [Ext] excludeFromFees #
       - modifiers: onlyOwner
    - [Ext] excludeFromMaxTransactionLimit #
       - modifiers: onlyOwner
    - [Ext] excludeFromMaxWalletLimit #
       - modifiers: onlyOwner
    - [Ext] blockAccount #
       - modifiers: onlyOwner
    - [Ext] unblockAccount #
       - modifiers: onlyOwner
    - [Ext] setWallets #
       - modifiers: onlyOwner
    - [Ext] setFeeOnWalletTransfers #
       - modifiers: onlyOwner
    - [Ext] setFeeOnSelectedWalletTransfers #
       - modifiers: onlyOwner
    - [Ext] setAllFeesToZero #
       - modifiers: onlyOwner
    - [Ext] resetAllFees #
       - modifiers: onlyOwner
    - [Ext] setBaseFeesOnBuy #
       - modifiers: onlyOwner
    - [Ext] setBaseFeesOnSell #
       - modifiers: onlyOwner
    - [Ext] setEruptionHour1BuyFees #
       - modifiers: onlyOwner
    - [Ext] setEruptionHour1SellFees #
       - modifiers: onlyOwner
    - [Ext] setEruptionHour2BuyFees #
       - modifiers: onlyOwner
    - [Ext] setEruptionHour2SellFees #
       - modifiers: onlyOwner
    - [Ext] setUniswapRouter #
       - modifiers: onlyOwner
    - [Ext] setMaxTransactionAmount #
       - modifiers: onlyOwner
    - [Ext] setMaxWalletAmount #
       - modifiers: onlyOwner
    - [Ext] setMinimumTokensBeforeSwap #
       - modifiers: onlyOwner
    - [Ext] claimBNBOverflow #
       - modifiers: onlyOwner
    - [Ext] timeSinceLastEruptionHour
    - [Ext] isInEruptionHour
    - [Ext] isInLaunch
    - [Ext] getBaseBuyFees
    - [Ext] getBaseSellFees
    - [Ext] geteruption1BuyFees
    - [Ext] geteruption1SellFees
    - [Ext] geteruption2BuyFees
    - [Ext] geteruption2SellFees
    - [Int] _transfer #
    - [Prv] _adjustTaxes #
    - [Prv] _setCustomSellTaxPeriod #
    - [Prv] _setCustomBuyTaxPeriod #
    - [Prv] _swapAndLiquify #
    - [Prv] _swapTokensForBNB #
    - [Prv] _addLiquidity #

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What is a SourceHat Audit?

Typically, a smart contract audit is a comprehensive review process designed to discover logical errors, security vulnerabilities, and optimization opportunities within code. A SourceHat 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.