In this series of security articles in simple language, we intend to address the issue of Code review (Audit) in smart contracts. Code review provides a detailed analysis of smart contract codes. Code revision is very important to protect the funds invested in Difai platforms. Given that all transactions in the blockchain are irreversible, this is even more important. After reviewing and testing the codes, a report is provided by the review team outlining the weaknesses of the codes and What can be improved. The development team will review the report after reading this report. Join BingMag to see how this review works.
Security review of smart contract codes is very common in the DeFi financial ecosystem. If you have invested in a blockchain project, your decision may be largely based on the results of a smart contract Code review. Let's take a look at the methods, tools, and results commonly seen in smart contract security reviews so we can make more informed decisions.
What is Code review in a smart contract?
In a review, the smart contract codes of a project are reviewed and evaluated. These contracts are usually written in the "Solidity" programming language and are provided through "GitHub". smart contract Code security scrutiny is more important to developers for multi-million dollar multi-user transaction projects. The Code review process usually involves the following four steps:
smart contract codes are provided to the review team for initial analysis.
2. The review team reports the results of the analysis to the developers so that the project can be modified based on these results.
3. The project team makes changes to the project based on the initial report of the deficiencies.
4. The final report is provided by the review team, which publishes all the deficiencies along with the corrections made.
smart contract review is essential when investing in new DeFi projects. This trend has become the standard for projects that want to attract a lot of users, including the review of smart contract codes by some companies in cybersecurity issues such as Certik, Quantstamp, Hacken and ConsenSys Diligence make more users trust these projects.
Why is there a need to review the smart contract code?
Since A lot of capital is processed or locked in through smart contracts, hackers have become very interested in them. In the event of a security breach in smart contracts, huge amounts of capital will be at risk. For example, about $ 60 million in ETH was lost in an attack on the DAO blockchain Atrium, which did not end there and eventually led to a hardfork on the Atrium network.
Since transactions in the blockchain Are irreversible, ensuring the security of the project Code is essential. The highly secure nature of blockchain technology makes it difficult to recover funds and resolve problems after a transaction, so it is best to avoid potential damage even if we have to pay high costs.
smart contract Code review How is it done?
Each security company uses its own techniques to review the code, but the overall process is almost the same. The steps for reviewing the Code are as follows:
1. The smart contract and project architecture are defined by the team and the purpose of the Code review is determined. This way, the review team for writing and using the Code knows What the goals of the project are.
2. An estimate of costs is provided.
3. The review team begins to perform manual and automated tests.
4. An initial report of the deficiencies found will be provided to the project team for troubleshooting.
5. The final report on project problems and modifications will be documented.
Code Review Methods
smart contract Code reviews are not just for security issues. Rather, they focus on the issue of efficiency and optimization. Some contracts carry out a complex set of transactions in order to complete their operations. Given that GAS costs are very high in networks such as Atrium, high-yield contracts can significantly reduce transaction costs.
Performance optimization also demonstrates the skill of the developer. Inefficient methods provide a better chance of failure They should be avoided. Saving transaction costs makes many users pay attention to the platforms.
Contract security vulnerabilities
Code review usually involves finding contract security vulnerabilities. Some of these weaknesses can be easily identified. But finding most of the weaknesses requires sophisticated techniques and strategies. For example, weak smart contracts can manipulate the market and implement "instant loan" attacks. To simulate attacks, security teams perform the "break test" technique. Some common vulnerabilities include the following:
Reentrancy: This attack occurs when a function calls an untrusted contract an external call. The unreliable contract then gives a reverse call to the main function to steal the assets.
2. Integer Overflow & Underflow: When a computational operation is performed by a smart contract, but the output exceeds the main memory capacity. (Usually 18 decimal places). This causes the result of the calculation to change.
3. Front Running: Front Running is the act of "performing a transaction before a specific transaction and with prior knowledge". If the codes are not properly structured, a warning will be issued to market traders. As a result, other people will misuse this information and trade on it.
Platform security flaws
Most reviews involve evaluating the host network Contracts and even the API used to communicate with the application are decentralized. A project may perform poorly against DDoS attacks or its website UI may be infected. In this case, users who have connected their wallets to malicious blockchain applications will be at risk.
What is a Code review report?
Review report At the end of the process is presented to the project. The development team is responsible for sharing the information in the report with users and members of their community. Otherwise, the transparency rating of the project will drop and fewer people will trust it. Most of these reports categorize the disadvantages found in different categories according to the level of security risk. They also state how long the project has a chance to fix the bug in order to receive the final report.
A standard report should include a summary of information, examples of redundant code, and recommendations. It should also explain where the flaws are found in the code. After actions are taken based on the initial report, the final report is published by the review team.
Introduction of Code review teams
Certificate (CertiK) is recognized as the most reputable Code review team and has evaluated the smart contract codes of hundreds of projects. Among them are PancakeSwap, BSC, the largest automaker. In the image below you can see a part of the Sertik review report for Pancake Swap.
The CertiK website is dedicated to reviewed projects so you can compare them. Each project has a score that indicates their level of security. In another section of this website you can see the list of projects under review.
ConsenSys was founded by Joseph Lubin (co-founder of Atrium) and is one of the most well-known cryptocurrencies in the development of blockchain. The team is tasked with reviewing Atrium smart Contracts. It is also equipped with an automated service for reviewing EVM contracts.
smart contract Code review cost
The exact cost of this work depends on the number of smart contracts reviewed And the credibility of the review team depends. A review process usually costs thousands of dollars. A large project would cost about $ 10,000 to review its code.
Fortunately, smart contract Code review has become a standard standard. Is. However, when all defa projects have this certificate, projects can no longer be evaluated on this basis, it is time for you to personally read the project review reports in order to make the final decision. Even without technical knowledge, some results can be reached and decisions made from the information contained in them. Of course, your investment decisions should always be large-scale and based on different criteria.