Coinsult

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Smart Contract Audit

2022-04-24T22:18:24+02:00

MIM Machine (Staking)

Binance Smart Chain

100% progress

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0 pending

0 pending

Coinsult

Audit

pending

Advanced manual smart contract audit not yet completed by Coinsult

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KYC

pending

Coinsult does not know the identity of the smart contract owner

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Advanced Manual
Smart Contract Audit

April 24, 2022

Audit requested by

MIM Machine (Staking)

Not deployed yet

MIM Machine (Staking) / Security Audit

Global Overview

Manual Code Review

In this audit report we will highlight the following issues:

Vulnerability Level

Total

Pending

Acknowledged

Resolved

0

0

0

0

8

0

0

0

0

0

0

0

0

0

0

0

MIM Machine (Staking) / Security Audit

Table of Contents

1. Audit Summary

1.1 Audit scope

1.2 Tokenomics

1.3 Source Code

2. Disclaimer

3. Global Overview

3.1 Informational issues

3.2 Low-risk issues

3.3 Medium-risk issues

3.4 High-risk issues

4. Vulnerabilities Findings

5. Contract Privileges

5.1 Maximum Fee Limit Check

5.2 Contract Pausability Check

5.3 Max Transaction Amount Check

5.4 Exclude From Fees Check

5.5 Ability to Mint Check

5.6 Ability to Blacklist Check

5.7 Owner Privileges Check

6. Notes

6.1 Notes by Coinsult

6.2 Notes by MIM Machine (Staking)

7. Contract Snapshot

8. Website Review

9. Certificate of Proof

MIM Machine (Staking) / Security Audit

Audit Summary

Project Name

MIM Machine (Staking)

Blockchain

Binance Smart Chain

Smart Contract Language

Solidity

Contract Address

Not deployed yet

Audit Method

Static Analysis, Manual Review

Date of Audit

24 April 2022

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.

MIM Machine (Staking) / Security Audit

Audit Scope

Coinsult was comissioned by MIM Machine (Staking) to perform an audit based on the following code:

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.

Contract not yet deployed

Audit Method

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.

MIM Machine (Staking) / Security Audit

Risk Classification

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.

Vulnerability Level

Description

Does not compromise the functionality of the contract in any way

Won't cause any problems, but can be adjusted for improvement

Will likely cause problems and it is recommended to adjust

Will definitely cause problems, this needs to be adjusted

Coinsult has four statuses that are used for each risk level. Below we explain them briefly.

Risk Status

Description

Total amount of issues within this category

Risks that have yet to be addressed by the team

The team is aware of the risks but does not resolve them

The team has resolved and remedied the risk

MIM Machine (Staking) / Security Audit

SWC Attack Analysis

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.

ID

Description

Status

Function Default Visibility

Passed

Integer Overflow and Underflow

Passed

Outdated Compiler Version

Passed

Floating Pragma

Passed

Unchecked Call Return Value

Passed

Unprotected Ether Withdrawal

Passed

Unprotected SELFDESTRUCT Instruction

Passed

Reentrancy

Passed

State Variable Default Visibility

Passed

Uninitialized Storage Pointer

Passed

Assert Violation

Passed

Use of Deprecated Solidity Functions

Passed

Delegatecall to Untrusted Callee

Passed

DoS with Failed Call

Passed

Transaction Order Dependence

Passed

Authorization through tx.origin

Passed

MIM Machine (Staking) / Security Audit

Block values as a proxy for time

Passed

Signature Malleability

Passed

Incorrect Constructor Name

Passed

Shadowing State Variables

Passed

Weak Sources of Randomness from Chain Attributes

Passed

Missing Protection against Signature Replay Attacks

Passed

Lack of Proper Signature Verification

Passed

Requirement Violation

Passed

Write to Arbitrary Storage Location

Passed

Incorrect Inheritance Order

Passed

Insufficient Gas Griefing

Passed

Arbitrary Jump with Function Type Variable

Passed

DoS With Block Gas Limit

Passed

Typographical Error

Passed

Right-To-Left-Override control character (U+202E)

Passed

Presence of unused variables

Passed

Unexpected Ether balance

Passed

Hash Collisions With Multiple Variable Length Arguments

Passed

Message call with hardcoded gas amount

Passed

Code With No Effects

Passed

Unencrypted Private Data On-Chain

Passed

MIM Machine (Staking) / Security Audit

Error Code

Description

Contract does not use a ReEntrancyGuard

One of the major dangers of calling external contracts is that they can take over the control flow. In the reentrancy attack (a.k.a. recursive call attack), a malicious contract calls back into the calling contract before the first invocation of the function is finished. This may cause the different invocations of the function to interact in undesirable ways.

				
					    function claimToken_M() public {
        User storage user = users[msg.sender];

        updateStakeBUSD_IP(msg.sender);
        uint256 tokenAmount = user.sM.unClaimedTokens;
        user.sM.unClaimedTokens = 0;

        _mint(msg.sender, tokenAmount);
        emit TokenOperation(msg.sender, "CLAIM", tokenAmount, 0);
    }

    function claimToken_T() public {
        User storage user = users[msg.sender];

        updateStakeToken_IP(msg.sender);
        uint256 tokenAmount = user.sT.unClaimedTokens;
        user.sT.unClaimedTokens = 0;

        _mint(msg.sender, tokenAmount);
        emit TokenOperation(msg.sender, "CLAIM", tokenAmount, 0);
    }
				
			

Recommendation

The best practices to avoid Reentrancy weaknesses are: Make sure all internal state changes are performed before the call is executed. This is known as the Checks-Effects-Interactions pattern, or use a reentrancy lock (ie. OpenZeppelin’s ReentrancyGuard.

MIM Machine (Staking) / Security Audit

Error Code

Description

Avoid relying on block.timestamp

block.timestamp can be manipulated by miners.

				
					    function getContractLaunchTime() public view returns (uint256) {
        return minZero(startTime, block.timestamp);
    }
				
			

Recommendation

Do not use block.timestampnow or blockhash as a source of randomness

Exploit scenario

				
					contract Game {

    uint reward_determining_number;

    function guessing() external{
      reward_determining_number = uint256(block.blockhash(10000)) % 10;
    }
}
				
			

Eve is a miner. Eve calls guessing and re-orders the block containing the transaction. As a result, Eve wins the game.

MIM Machine (Staking) / Security Audit

Error Code

Description

Too many digits

Literals with many digits are difficult to read and review.

				
					    function SET_SELL_LIMIT(uint256 value) external {
        require(msg.sender == ADMIN, "Admin use only");
        require(value >= 40000);
        SELL_LIMIT = value * 1 ether;
    }
				
			

Recommendation

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.

MIM Machine (Staking) / Security Audit

Error Code

Description

Functions that send Ether to arbitrary destinations

Unprotected call to a function sending Ether to an arbitrary address.

				
					    function stakeBUSD(uint256 _amount) public payable {
        require(block.timestamp > startTime); 
        require(_amount >= MIN_INVEST_AMOUNT); // added min invest amount
        token.transferFrom(msg.sender, address(this), _amount); // added

        uint256 fee = _amount.mul(FEE).div(PERCENT_DIVIDER); // calculate fees on _amount and not msg.value

        token.transfer(DEV_POOL, fee);

        User storage user = users[msg.sender];

        if (user.sM.totalStaked == 0) {
            user.sM.checkpoint = maxVal(now, startTime);
            totalUsers++;
        } else {
            updateStakeBUSD_IP(msg.sender);
        }

        user.sM.lastStakeTime = now;
        user.sM.totalStaked = user.sM.totalStaked.add(_amount);
        totalBUSDStaked = totalBUSDStaked.add(_amount);
    }
				
			

Recommendation

Ensure that an arbitrary user cannot withdraw unauthorized funds.

Exploit scenario

				
					contract ArbitrarySend{
    address destination;
    function setDestination(){
        destination = msg.sender;
    }

    function withdraw() public{
        destination.transfer(this.balance);
    }
}
				
			

Bob calls setDestination and withdraw. As a result he withdraws the contract’s balance.

MIM Machine (Staking) / Security Audit

Error Code

Description

Unchecked transfer

The return value of an external transfer/transferFrom call is not checked.

				
					    function stakeToken(uint256 tokenAmount) public {
        User storage user = users[msg.sender];
        require(now >= startTime, "Stake not available yet");
        require(
            tokenAmount <= balanceOf(msg.sender),
            "Insufficient Token Balance"
        );

        if (user.sT.totalStaked == 0) {
            user.sT.checkpoint = now;
        } else {
            updateStakeToken_IP(msg.sender);
        }

        _transfer(msg.sender, address(this), tokenAmount);
        user.sT.lastStakeTime = now;
        user.sT.totalStaked = user.sT.totalStaked.add(tokenAmount);
        totalTokenStaked = totalTokenStaked.add(tokenAmount);
    }
				
			

Recommendation

Use SafeERC20, or ensure that the transfer/transferFrom return value is checked.

Exploit scenario

				
					contract Token {
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
}
contract MyBank{  
    mapping(address => uint) balances;
    Token token;
    function deposit(uint amount) public{
        token.transferFrom(msg.sender, address(this), amount);
        balances[msg.sender] += amount;
    }
}
				
			

Several tokens do not revert in case of failure and return false. If one of these tokens is used in MyBankdeposit will not revert if the transfer fails, and an attacker can call deposit for free..

MIM Machine (Staking) / Security Audit

Error Code

Description

Missing events arithmetic

Detect missing events for critical arithmetic parameters.

				
					    function SET_MIN_INVEST_AMOUNT(uint256 value) external {
        require(msg.sender == ADMIN, "Admin use only");
        require(value >= 5);
        MIN_INVEST_AMOUNT = value * 1 ether;
    }

    function SET_SELL_LIMIT(uint256 value) external {
        require(msg.sender == ADMIN, "Admin use only");
        require(value >= 40000);
        SELL_LIMIT = value * 1 ether;
    }
				
			

Recommendation

Emit an event for critical parameter changes.

Exploit scenario

				
					contract C {

  modifier onlyAdmin {
    if (msg.sender != owner) throw;
    _;
  }

  function updateOwner(address newOwner) onlyAdmin external {
    owner = newOwner;
  }
}
				
			

updateOwner() has no event, so it is difficult to track off-chain changes in the buy price.

MIM Machine (Staking) / Security Audit

Error Code

Description

Conformance to Solidity naming conventions

Allow _ at the beginning of the mixed_case match for private variables and unused parameters.

				
					    function SET_MIN_INVEST_AMOUNT(uint256 value) external {
        require(msg.sender == ADMIN, "Admin use only");
        require(value >= 5);
        MIN_INVEST_AMOUNT = value * 1 ether;
    }

    function SET_SELL_LIMIT(uint256 value) external {
        require(msg.sender == ADMIN, "Admin use only");
        require(value >= 40000);
        SELL_LIMIT = value * 1 ether;
    }
				
			

Recommendation

Follow the Solidity naming convention.

Rule exceptions

  • Allow constant variable name/symbol/decimals to be lowercase (ERC20).
  • Allow _ at the beginning of the mixed_case match for private variables and unused parameters.

MIM Machine (Staking) / Security Audit

Error Code

Description

Code With No Effects

Detect the usage of redundant statements that have no effect.

				
					    function getContractBUSDBalance() public view returns (uint256) {
        // return address(this).balance;
        return token.balanceOf(address(this));
    }
				
			

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.

MIM Machine (Staking) / Security Audit

Other Owner Privileges Check

Error Code

Description

CEN-100

Coinsult lists all important contract methods which the owner can interact with.

⚠ Owner can set minimum investment amount

⚠ Owner can set sell limit
– Note from the MIM machine team: The sell limit will always be at least 40,000 ether

 

 

MIM Machine (Staking) / Security Audit

Notes

Notes by MIM Machine (Staking)

No notes provided by the team.

Notes by Coinsult

No notes provided by Coinsult

MIM Machine (Staking) / Security Audit

Contract Snapshot

This is how the constructor of the contract looked at the time of auditing the smart contract.

				
					contract MIMMachine is Token {
    uint256 private startTime = now - 1 days; 

    address payable private ADMIN;
    address payable private DEV_POOL;

    uint256 public totalUsers;
    uint256 public totalBUSDStaked;
    uint256 public totalTokenStaked;

    uint256 private constant FEE = 100; // 10% fee
    uint256 private constant MANUAL_AIRDROP = 50000 ether; // marketing + giveaways

    uint256 private constant PERCENT_DIVIDER = 1000;
    uint256 private constant PRICE_DIVIDER = 1 ether;
    uint256 private constant TIME_STEP = 1 days;
    uint256 private constant TIME_TO_UNSTAKE = 7 days;


    // Configurables
    uint256 public MIN_INVEST_AMOUNT = 5 ether;
    uint256 public SELL_LIMIT = 50000 ether;
    uint256 public BUSD_DAILYPROFIT = 20; // 2%
    uint256 public TOKEN_DAILYPROFIT = 40; // 4%

    mapping(address => User) private users;
    mapping(uint256 => uint256) private sold;

    struct Stake {
        uint256 checkpoint;
        uint256 totalStaked;
        uint256 lastStakeTime;
        uint256 unClaimedTokens;
    }

    struct User {
        Stake sM; // staked BUSD
        Stake sT; // staked BMT
    }

    event TokenOperation(
        address indexed account,
        string txType,
        uint256 tokenAmount,
        uint256 trxAmount
    );
				
			

MIM Machine (Staking) / Security Audit

Website Review

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. 

Pretty basic website, could use some more development.

Type of check

Description

Mobile friendly?

Contains jQuery errors?

Is SSL secured?

Contains spelling errors?

MIM Machine (Staking) / Security Audit

Certificate of Proof

MIM Machine (Staking)

Audited by Coinsult.net

Date: 24 April 2022

MIM Machine (Staking) / Security Audit

Disclaimer

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.

Coinsult

coinsult.net

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