Smart Contract Audit Report
Helena Financial is a new BEP-20 token on the Binance Smart Chain with an elastic supply that performs automatic liquidity adds.
For this audit, we reviewed the project team's HelenaFinancial contract at 0xE350b08079f9523B24029B838184f177baF961Ff on the Binance Smart Chain Mainnet.
Please ensure trust in the team prior to investing as they have substantial control in the ecosystem.
Date: April 8th, 2022.
Finding #1 - HelenaFinancial - LowDescription: There are four instances in the takeFee() function where multiplication is performed on the result of a division.Risk/Impact: Division can lead to integer truncation, therefore dividing and subsequently multiplying can cause results to lose precision and become less accurate.
uint256 feeAmount = gonAmount.div(feeDenominator).mul(_totalFee); _gonBalances[sControl] = _gonBalances[sControl].add( gonAmount.div(feeDenominator).mul(sControlFee) ); _gonBalances[address(this)] = _gonBalances[address(this)].add( gonAmount.div(feeDenominator).mul(_hellenicFee.add(vaultFee)) ); _gonBalances[autoLiquidityFund] = _gonBalances[autoLiquidityFund].add( gonAmount.div(feeDenominator).mul(liquidityFee) );
Recommendation: We recommend modifying these calculations to perform all multiplication before division.
Resolution: The team has not yet addressed this issue.
Finding #2 - HelenaFinancial - InformationalDescription: Several state variables can never be modified, but are not declared constant.Recommendation: These state variables should be declared constant for additional gas savings on each call.
_decimals, _name, _symbol, feeDenominator, hellenicFee, sControlFee, sellFee, swapEnabled, vaultFee
- The initial supply of the token is set to 500,000 $HELENA.
- No mint or burn functions are present, though the circulating supply can be reduced by sending tokens to the 0x..dead address.
- At the time of writing this report, 91.38% of the total supply belongs to an unverified contract.
- The remaining 8.62% of the total supply belongs to the owner.
- There is a Liquidity fee, Hellenic fee, Vault Fee, and sControl fee on all transfers via Pancakeswap where neither the sender nor the recipient is excluded from fees.
- There is an additional Sell fee added on all sell transactions via Pancakeswap.
- Blacklisted contracts are not permitted to transfer tokens.
- The contract features an auto-rebase mechanism that is triggered on token transfers when the following conditions are met:
- The auto-rebase mechanism is enabled by the team.
- The token has not reached the maximum supply.
- The caller is not initiating a buy transaction via Pancakeswap.
- The contract is not currently swapping tokens, performing a rebase, or performing an automatic liquidity add.
- 15 minutes have passed since this functionality has previously occurred.
- During a rebase, tokens are automatically added to the total supply. The newly added tokens are distributed proportionally amongst holders in a frictionless manner.
- The number of tokens added to the total supply is dependent on the total supply at the time of rebasing and the time since deployment.
- The rebase function properly calls sync() on the Pancakeswap Pair contract to prevent theft-of-liquidity attacks that have occurred with other rebase tokens.
- An automatic liquidity add will also occur on token transfers if at least 1 day has passed since the previous automatic liquidity add.
- A liquidity-add is funded by selling half of the tokens collected as liquidity 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 wallet controlled by the team. We recommend that the team lock these newly acquired LP tokens.
- The tokens collected through the Hellenic fee and Vault Fee are swapped for BNB and sent to the team's Hellenic wallet and Vault wallet respectively.
- The tokens collected through the sControl fee are sent to the team's sControl wallet.
- The contract utilizes SafeMath libraries to prevent any overflows/underflows.
- The owner can manually set the rebase rate to any value at any time.
- The owner can enable/disable automatic liquidity adds and the auto-rebase mechanism at any time.
- The owner can add/remove any contract address from the transfer blacklist at any time. EOAs cannot be blacklisted.
- The owner can include/exclude accounts from transfer fees at any time.
- The owner can swap all of the $HELENA in the contract for BNB and send it to the team's Hellenic wallet at any time.
- The owner can update the Pancakeswap Pair address, Hellenic wallet, Liquidity wallet, Vault wallet, and sControl wallet at any time.
|Arbitrary Jump/Storage Write||N/A||PASS|
|Centralization of Control||WARNING|
|Delegate Call to Untrusted Contract||N/A||PASS|
|Dependence on Predictable Variables||N/A||PASS|
|Improper Authorization Scheme||N/A||PASS|
|Outdated Compiler Version||N/A||PASS|
|Overall Contract Safety||PASS|
($) = payable function # = non-constant function Int = Internal Ext = External Pub = Public + [Lib] SafeMathInt - [Int] mul - [Int] div - [Int] sub - [Int] add - [Int] abs + [Lib] SafeMath - [Int] add - [Int] sub - [Int] sub - [Int] mul - [Int] div - [Int] div - [Int] mod + [Int] IERC20 - [Ext] totalSupply - [Ext] balanceOf - [Ext] allowance - [Ext] transfer # - [Ext] approve # - [Ext] transferFrom # + [Int] IPancakeSwapPair - [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] IPancakeSwapRouter - [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 ($) - [Ext] quote - [Ext] getAmountOut - [Ext] getAmountIn - [Ext] getAmountsOut - [Ext] getAmountsIn - [Ext] removeLiquidityETHSupportingFeeOnTransferTokens # - [Ext] removeLiquidityETHWithPermitSupportingFeeOnTransferTokens # - [Ext] swapExactTokensForTokensSupportingFeeOnTransferTokens # - [Ext] swapExactETHForTokensSupportingFeeOnTransferTokens ($) - [Ext] swapExactTokensForETHSupportingFeeOnTransferTokens # + [Int] IPancakeSwapFactory - [Ext] feeTo - [Ext] feeToSetter - [Ext] getPair - [Ext] allPairs - [Ext] allPairsLength - [Ext] createPair # - [Ext] setFeeTo # - [Ext] setFeeToSetter # + Ownable - [Pub]
# - [Pub] owner - [Pub] isOwner - [Pub] renounceOwnership # - modifiers: onlyOwner - [Pub] transferOwnership # - modifiers: onlyOwner - [Int] _transferOwnership # + ERC20Detailed (IERC20) - [Pub] # - [Pub] name - [Pub] symbol - [Pub] decimals + HelenaFinancial (ERC20Detailed, Ownable) - [Pub] # - modifiers: ERC20Detailed,Ownable - [Ext] setRebaseRate # - modifiers: onlyOwner - [Ext] toggleOwnerRebase # - modifiers: onlyOwner - [Int] rebase # - [Ext] transfer # - modifiers: validRecipient - [Ext] transferFrom # - modifiers: validRecipient - [Int] _basicTransfer # - [Int] _transferFrom # - [Int] takeFee # - [Int] addLiquidity # - modifiers: swapping - [Int] swapBack # - modifiers: swapping - [Ext] withdrawAllToHellenic # - modifiers: swapping,onlyOwner - [Int] shouldTakeFee - [Int] shouldRebase - [Int] shouldAddLiquidity - [Int] shouldSwapBack - [Ext] setAutoRebase # - modifiers: onlyOwner - [Ext] setAutoAddLiquidity # - modifiers: onlyOwner - [Ext] allowance - [Ext] decreaseAllowance # - [Ext] increaseAllowance # - [Ext] approve # - [Ext] checkFeeExempt - [Pub] getCirculatingSupply - [Ext] isNotInSwap - [Ext] manualSync # - [Ext] setFeeReceivers # - modifiers: onlyOwner - [Ext] getLiquidityBacking - [Ext] setWhitelist # - modifiers: onlyOwner - [Ext] setBotBlacklist # - modifiers: onlyOwner - [Ext] setPairAddress # - modifiers: onlyOwner - [Ext] setLP # - modifiers: onlyOwner - [Ext] totalSupply - [Ext] balanceOf - [Int] isContract - [Pub] gonsForBalance - [Pub] balanceForGons - [Pub] index - [Ext] ($)
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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.