In this audit report we will highlight the following issues:
Coinsult checked the following privileges:
More owner priviliges are listed later in the report.
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.
Note that we only audited the code available to us on this URL at the time of the audit. If the URL is not from any block explorer (main net), it may be subject to change. Always check the contract address on this audit report and compare it to the token you are doing research for.
28-04-2022: Redeployed new contract, old audit is no longer valid.
Coinsult’s manual smart contract audit is an extensive methodical examination and analysis of the smart contract’s code that is used to interact with the blockchain. This process is conducted to discover errors, issues and security vulnerabilities in the code in order to suggest improvements and ways to fix them.
Coinsult uses software that checks for common vulnerability issues within smart contracts. We use automated tools that scan the contract for security vulnerabilities such as integer-overflow, integer-underflow, out-of-gas-situations, unchecked transfers, etc.
Coinsult’s manual code review involves a human looking at source code, line by line, to find vulnerabilities. Manual code review helps to clarify the context of coding decisions. Automated tools are faster but they cannot take the developer’s intentions and general business logic into consideration.
Coinsult uses certain vulnerability levels, these indicate how bad a certain issue is. The higher the risk, the more strictly it is recommended to correct the error before using the contract.
Coinsult has four statuses that are used for each risk level. Below we explain them briefly.
The Smart Contract Weakness Classification Registry (SWC Registry) is an implementation of the weakness classification scheme proposed in EIP-1470. It is loosely aligned to the terminologies and structure used in the Common Weakness Enumeration (CWE) while overlaying a wide range of weakness variants that are specific to smart contracts.
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Too many digits
Literals with many digits are difficult to read and review.
_amountSupply = 100000000 * (10 ** uint256(decimals()));
Recommendation
Use: Ether suffix, Time suffix, or The scientific notation
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.
Conformance to Solidity naming conventions
Allow _ at the beginning of the mixed_case match for private variables and unused parameters.
contract APE_TOKEN is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint256 private _amountSupply;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor() {
_name = "Ape Rewards";
_symbol = "APER";
Recommendation
Follow the Solidity naming convention.
Rule exceptions
ERC20
)._
at the beginning of the mixed_case
match for private variables and unused parameters.Code With No Effects
Detect the usage of redundant statements that have no effect.
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
Recommendation
Remove redundant statements if they congest code but offer no value.
Exploit scenario
contract RedundantStatementsContract {
constructor() public {
uint; // Elementary Type Name
bool; // Elementary Type Name
RedundantStatementsContract; // Identifier
}
function test() public returns (uint) {
uint; // Elementary Type Name
assert; // Identifier
test; // Identifier
return 777;
}
}
Each commented line references types/identifiers, but performs no action with them, so no code will be generated for such statements and they can be removed.
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function harvest(address recipient, uint256 amount) public virtual returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function unStake(address recipient, uint256 amount) public virtual returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function withdraw(address recipient, uint256 amount) public virtual returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function unLock(address recipient, uint256 amount) public virtual returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
Recommendation
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.
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.
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.
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.
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.
Coinsult tests if the owner of the smart contract needs to manually enable trading before everyone can buy & sell. If the owner needs to manually enable trading, this poses a high centralization risk.
If the owner needs to manually enable trading, make sure to check if the project has a SAFU badge or a trusted KYC badge. Always DYOR when investing in a project that needs to manually enable trading.
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.
Coinsult lists all important contract methods which the owner can interact with.
This is how the constructor of the contract looked at the time of auditing the smart contract.
contract APE_TOKEN is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint256 private _amountSupply;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor() {
_name = "Ape Rewards";
_symbol = "APER";
_amountSupply = 100000000 * (10 ** uint256(decimals()));
require(msg.sender != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), msg.sender, _amountSupply);
_totalSupply += _amountSupply;
_balances[msg.sender] += _amountSupply;
emit Transfer(address(0), msg.sender, _amountSupply);
_afterTokenTransfer(address(0), msg.sender, _amountSupply);
}
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.
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.