Smart Contract Audit Report
Altcoins Online 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 AltcoinsOnline contract at 0x2245416060e8e5a3d35e013f77c86975262fea70 on the Binance Smart Chain Mainnet.
Please ensure trust in the team prior to investing as they have substantial control in the ecosystem.
Date: March 29th, 2022.
Updated: April 4th, 2022 to reflect the project team's newly deployed Mainnet address that resolves Finding #1.
Finding #1 - AltcoinsOnline - Low (Resolved)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 removed this functionality from the contract.
Finding #2 - AltcoinsOnline - InformationalDescription: Several functions are declared public, but are never called internally.Recommendation: These functions should be declared external for additional gas savings on each call.
name, symbol, decimals, totalSupply, transfer, allowance, approve, transferFrom, increaseAllowance, decreaseAllowance, isExcludedFromReward, totalFees, deliver, reflectionFromToken, excludeFromReward, excludeFromFee, includeInFee, setSwapAndLiquifyEnabled, isExcludedFromFee
Finding #3 - AltcoinsOnline - 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, _tTotal, numTokensSellToAddToLiquidity
- The total supply of the token is set to 2.6 million $AOL [2,600,000].
- 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 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.
- There is a Tax fee and a Liquidity fee on all transfers where neither the sender nor the recipient is excluded from fees.
- 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 1,000 tokens in 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 owner. We recommend that the team lock these newly acquired LP tokens.
- The contract utilizes the SafeMath library to protect against overflows/underflows.
- The contract complies with the BEP-20 token standard.
- The owner can modify the Tax fee and Liquidity fee to any percentages at any time.
- The owner can exclude and include accounts from transfer fees and reward distribution.
- The owner can set the maximum transaction amount to any value at any time.
- The owner can withdraw any BNB from the contract at any time.
- The owner can send any $AOL tokens from the contract address to the 0x00 address at any time.
External Threat Results
|Arbitrary Storage Write||N/A||PASS|
|Centralization of Control||WARNING|
|Delegate Call to Untrusted Contract||N/A||PASS|
|Dependence on Predictable Variables||N/A||PASS|
|State Change External Calls||N/A||PASS|
|User Supplied Assertion||N/A||PASS|
|Critical Solidity Compiler||N/A||PASS|
|Overall Contract Safety||PASS|
($) = 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 # + [Lib] SafeMath - [Int] add - [Int] sub - [Int] sub - [Int] mul - [Int] div - [Int] div - [Int] mod - [Int] mod + Context - [Int] _msgSender - [Int] _msgData + [Lib] Address - [Int] isContract - [Int] sendValue # - [Int] functionCall # - [Int] functionCall # - [Int] functionCallWithValue # - [Int] functionCallWithValue # - [Prv] _functionCallWithValue # + Ownable (Context) - [Int]
# - [Pub] owner - [Pub] renounceOwnership # - modifiers: onlyOwner - [Pub] transferOwnership # - 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 # + AltcoinsOnline (Context, IERC20, Ownable) - [Pub] # - [Pub] name - [Pub] symbol - [Pub] decimals - [Pub] totalSupply - [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] excludeFromFee # - modifiers: onlyOwner - [Pub] includeInFee # - modifiers: onlyOwner - [Ext] setTaxFeePercent # - modifiers: onlyOwner - [Ext] setLiquidityFeePercent # - modifiers: onlyOwner - [Ext] setMaxTxPercent # - 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 - [Prv] removeAllFee # - [Prv] restoreAllFee # - [Pub] isExcludedFromFee - [Prv] _approve # - [Prv] _transfer # - [Prv] swapAndLiquify # - modifiers: lockTheSwap - [Prv] swapTokensForEth # - [Prv] addLiquidity # - [Prv] _tokenTransfer # - [Prv] _transferStandard # - [Prv] _transferToExcluded # - [Prv] _transferFromExcluded # - [Ext] withdrawStuckBNBs # - modifiers: onlyOwner - [Ext] burnStuckTokens # - 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.