This document contains confidential information about IT systems and intellectual properties of the customer, as well as information about potential vulnerabilities and methods of their exploitation. This confidential information is for internal use by the customer only and shall not be disclosed to third parties
Document
| Name : | Token Contract Code Review and Security Analysis Report for IQ |
| Date : | 01/18/2019 |
| Audited By: | Michael Yeates - eosDAC |
- Reviewer Introduction
- Scope
- Executive Summary
- Contract Overview
- Actions and Parameters
- Severity Levels and explanation
- Audit Overview
- Informational statements
- Conclusion
- Disclaimers
- Technical Disclaimer
- Appendix A. Evidences
- Appendix B. Automated tools reports
Add reviewer introduction here
The scope of the project is the Everipedia IQ token contract, which can be found on the link below
We have scanned the everipediaiq contract for commonly known and more specific vulnerabilities. Here are some of the commonly known vulnerabilities that are considered.
(Audited commit 32f3c8ee2abfff27051754811a679eed593dc7dd)
- Numerical Overflow All numerical calculations use the eosio::asset class which are protected against potential overflow and underflow in numeric operations.
- Authorization Checks - All actions in the contract require authorisation using the
require_auth()built in checks. - Apply checks - Uses the standard
EOSIO_DISPATCHfor the apply dispatching. This has checks for the correct contract id and and ensures only declared actions are responded to by the contract. - String Parameter length - To ensure string parameters to actions are not unbounded in length the string parameters for all the relevant actions have been capped in length to 256 characters.
- RAM fill up protection (RAM DoS) - storing all items in the user's RAM space rather than the contract RAM except for actions requiring the contract's _self permission.
- CPU bandwidth protection (CPU DoS) - All actions in the contract are initiated by the caller of the contract therefore the caller would need to have enough staked CPU resources to perform the called action.
- Source code version - The contract code was compiled with EOSIO v1.4.2.
The code has been reviewed by peers and available as open source code on GitHub since before it was first deployed to the main net in July 2018. The original code was based on the eosio.token source code as written and tested by Block One. It has also been kept up to date with changes to the eosio.token contract since then. The eosio.token contract has been thoroughly tested and exercised through replication by many tokens on the network and through our own automated and manual testing on the Jungle testnet. We have maintained the code in that time performing incremental updates to improve performance, security and functionality. As yet we have had cause for concern about security issues and no report of any loss of value through a security vulnerability. The customised features we have added to the contract include locking the ability to stake IQ tokens, and are believed to be low risk in relation to security concerns in the code.
everipediaiq contract is built up on eosio.token contract with additional custom parameters and functionality for IQ
eosio.token Token Contract https://github.com/EOSIO/eosio.contracts/tree/master/eosio.token
- Contract name – everipediaiq
- Symbol – IQ
- Decimals – 3
everipediaiq contract has 6 Actions
Parameters:
- from : is a type of eosio name
- to : is a type of eosio name
- quantity : is a type of eosio asset
- memo : is a string with a maximum of 256 characters
Intent: The intent of {{ transfer }} is to allow an account {{ from }} to send {{ quantity }} tokens to another account {{ to }}. A note {{ memo }} can be sent to the receiver.
Term: The transfer action represents a change in the asset balances of the accounts involved in the transaction.
Parameters:
- from : is a type of eosio name for the owner of the tokens to burn.
- quantity : is a type of eosio asset
- memo : is a string with a maximum of 256 characters
Intent: The intent of {{ burn }} is to allow a user to burn {{ quantity }} tokens that belong to them. A note {{ memo }} can be sent to the receiver.
Term: The burn action lasts for the duration of the processing of the contract. The reduction in token supply persists on the deployed contract as long as it is active.
Parameters:
- from : is a type of eosio name for the owner of the tokens to burn.
- quantity : is a type of eosio asset
- memo : is a string with a maximum of 256 characters
Intent: This function is deprecated. It used to be in the transfer function, but is now excluded.
Parameters:
- issuer : is a type of eosio name
- maximum_supply : is a type of asset
Intent: The intent of {{ create }} is to create a new token with a {{ maximum supply }} as indicated. The asset is created in the format of {{ number of tokens to 3 decimal places token symbol }} for example 1000.000 IQ will create a IQ token with a maximum number of units of 1000.000.
Term: The act of creation of this asset will expires at the conclusion of code execution. The asset will then persist on the deployed contract as long as it is active.
Parameters:
- to : is a type of eosio name to issue tokens to
- quantity : is a type of eosio asset
- memo : is a string with a maximum of 256 characters
Intent: The intent of {{ issue }} is to issue tokens {{ quantity }} and send them to the account specified {{ to }} using the transfer action. This requires the contract owner account. A note {{ memo }} can be sent to the receiver.
Term: The action lasts for the duration of the processing of the contract.
Parameters:
- staker : eosio name of the person staking IQ
- amount : the amount of IQ to stake
Intent: The intent of {{ brainmeiq }} is to allow the {{ staker }} to stake an {{ amount }} of IQ tokens in order to gain editing and voting power on the IQ article contract.
Term: The stake can be re-claimed back for IQ after 21 days.
| Critical | Critical vulnerabilities are severe as they are easy to exploit and can result in loss of tokens etc. |
| High | High level vulnerabilities are hard to exploit but can have an impact on smart contract execution, e.g. open access to an important function |
| Medium | Medium level vulnerabilities are important to fix but can't lead to loss of tokens |
| Low | Low-level vulnerabilities are mostly outdated code, unused code related. They have very low to no impact on smart contract execution |
| Lowest/Code/Style/Info | Lowest level of vulnerabilities, code style violations and info statement can't affect smart contract execution and can be ignored |
No critical severity vulnerabilities were identified
No high severity vulnerabilities were identified
No medium severity vulnerabilities were identified
No Low severity vulnerabilities were identified.
No code style issues were identified.
None
During the audit the contract was manually reviewed, the auditor found no security issues that required fixing.
The audit does not give any warranties on the security of the code. A single audit may not be enough, we highly encourage several independent audits and public bug bounties to ensure optimum security of the smart contracts.
Smart contract built on the top of EOSIO blockchain allow for a lot of features to be covered by tests, but the Turing completeness of C++ programming language and flexibility of the language leaves some space for unexpected runtime exceptions.
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