Smart Contract Audit – What Is It and Why It's Important

What Is a Smart Contract Audit?

The process of auditing entails a systematic review and thorough analysis of the smart contract code to detect any erroneous coding or security vulnerabilities that may exist, highlighting the critical role of smart contract development in ensuring the integrity and security of blockchain-based systems. This guarantees the dependability of the blockchain applications and offers solutions to troubleshoot issues. Typically, smart contract security audits entail utilizing analysis tools and conducting manual code analysis.

Why Is It Important?

Currently, security is a critical issue when it comes to deploying a new product. Failure to address inefficiency, security, and misbehavior concerns when developing smart contracts on a blockchain network may lead to significant additional expenses.

Businesses are worried about deployment because of their irreversible nature. Additionally, due to smart contract vulnerabilities, the complete contract and its associated assets can be lost. Thus, the need for smart contract auditing has emerged as a necessity in recent times due to the following rationales, emphasizing the essential role of smart contract development in maintaining the security and reliability of blockchain-based applications.

• Conducting code audits early in the development process is advisable to prevent critical issues from arising post-launch, which can be expensive to fix.
• An experienced security smart contract auditor should manually double-check the code to eliminate false results.
• To prevent security attacks, it is important to be vigilant for any security vulnerabilities while writing and modifying code.
• Implementing a smart contract security audit provides decentralized product owners with the assurance that their code is secure. This results in enhanced security measures.
• The smart contract auditing process facilitates a continuous security assessment, enabling developers to conduct ongoing security assessments and improve their development environment.
• The vulnerability report generates an executive summary, vulnerability details, and mitigation advice for analytical purposes.

Types of Audits

Audits may be classified in a variety of ways, depending on the specifics of individual endeavors. In what follows, we’ll delve into the processes of both human and machine auditing.

Automated auditing

Implementing automated smart contract auditing results in a significant reduction in response time by eliminating the need for human auditors. The audit program detects program parameters for identifying common coding errors. The efficacy of this audit is directly proportional to the effectiveness of the automated analysis tool employed.

Manual auditing

This audit is executed as a distinct undertaking via the guidance of proficient smart contract developers. During the audit, the developers will review the code, thoroughly evaluate the application’s requirements, and verify that the project executes the expected operations.

Methods for Auditing

Gas efficiency

The primary emphasis of smart contract audits is not limited to ensuring the security of the blockchain. Developers also consider efficiency and optimization. Certain contracts may involve a complex sequence of transactions to fulfill their intended purpose. Optimizing contracts can significantly reduce transaction costs, which is particularly important given the high gas fees associated with networks such as Ethereum.

Optimizing performance is a key measure of a developer’s proficiency. Avoid inefficient steps as they increase the likelihood of failure. Insufficient gas limit usage can lead to the failure of smart contract execution, particularly during periods of high gas costs.

Contract vulnerabilities

Most tasks involved in audits entail scrutinizing contracts for potential security weaknesses. Although certain problems may be apparent, numerous exploits require sophisticated techniques and strategies to deplete funds. Weak smart contracts can be exploited for flash loan attacks through market manipulation. To identify such issues, developers initiate the process of break testing and simulate malicious attacks on the smart contract. Some of the typical vulnerabilities that developers need to be aware of are:

• Reentrancy issues

This occurs when a smart contract initiates an external call to another external contract prior to resolving any effects. The external contract can recursively invoke the primary smart contract and perform interactions that are not authorized since the balance of the primary contract has not been updated yet.

• Overflows and underflows of integers

If an arithmetic operation performed by a smart contract results in an output that exceeds the storage capacity, an error will occur (usually 18 decimal places). This may result in inaccurate calculations.

• Front-running opportunities

Poorly organized code may indicate potential market buys or sells. This can enable third-party users to utilize the data and leverage it for their personal gain.

Advantages

Performing an audit on the smart contract for your project is crucial for enhancing its security, usability, and reliability.

Fixing potentially costly vulnerabilities

Untimely identification of coding flaws can lead to substantial losses. A vulnerability in the signature verification protocol of an escrow system called Wormhole allowed hackers to steal 120,000 wETH, equivalent to $326 million. Thus, a smart contract audit may be considered an investment rather than an expense.

Getting helpful advice from established professionals

After the completion of the audit, the code is meticulously reviewed by the audit providers. The audit team furnishes the project team with suggestions and recommendations to effect the required modifications based on the identified concerns.

Giving your community extra peace of mind

Performing a security audit on your project by professionals in the field and making necessary adjustments can provide your user base with added assurance. The users exhibit enhanced trust in the applications and utilize them more confidently.

When Is It Necessary to Conduct an Audit?

Due to the irreversible nature of smart contract deployment, developers must address businesses’ concerns regarding the viability of their projects. The complete contract and its related assets may be lost due to security vulnerabilities. The following projects require a smart contract audit:

Token contracts/crowdsales

Implement a crowdsale to distribute tokens utilizing a professional token smart contract audit that supports various programming languages and protocols such as C++, Solidity, and JavaScript.

DeFi projects

In 2022, DeFi was responsible for over 90% of all cryptocurrency hacks. When working with intricate systems like those that utilize smart contracts, it is advisable to employ DeFi audits to ensure their security, underscoring the importance of partnering with a defi development company that specializes in comprehensive security assessments and audits.

dApps

Performing a security audit for a dApp is essential to ensure its secure deployment on a blockchain platform. The backend of a dApp is coded using a smart contract, similar to other web applications. It is crucial to conduct a comprehensive security audit to identify and eliminate any potential vulnerabilities.

NFTs and marketplace

Autonomous platforms facilitate the trading of digital assets, enabling users to engage in NFT transactions. The possession of private keys to all assets within a platform highlights the significance of maintaining uncompromised security.

Key Vulnerabilities

There is always a possibility of errors or oversights during the smart contract development of the security architecture. The following are potential security vulnerabilities that smart contracts may contain:

Timestamp dependency

The contract’s logic relies on the present time. This implies that the developer can alter the output of the execution by modifying the device’s current time.

Function visibility errors

Solidity is a programming language that developers use to implement smart contracts. The language’s default visibility modifier is set to public. If visibility is not defined for a private function, there is a risk of contract destruction if anyone calls the Destruct function.

Reentrancy attacks

A reentrancy attack is a vulnerability that arises when a function initiates an external call to another contract that cannot be trusted. This issue may arise as a result of the developer’s lack of concern and disregard for the task at hand. Due to the attack, the unreliable contract may perform a recursive invocation to the initial function to deplete the funds.

Random number vulnerability

Attackers could potentially use random number generation (RNG) to accurately predict the random number generated by the contract.

Failure in differentiating humans and contracts

Not properly distinguishing between a human or a contract invoking the smart contract could lead to unpredictable consequences. By accurately predicting the timestamp of a contract, a developer can earn money through the airdrop function in the popular Fomo3D game. This can be achieved by correctly guessing the block.

Spelling mistakes

Constructors are frequently utilized in initializing contracts and identifying their owners. The function Object() { [native code] } function in Solidity calls upon contract deployment to initialize the state variables. During the development process, a misspelled function can go unnoticed by the compiler. This can result in the function being accessible to the public in constructors.

How to Perform an Audit

Performing an audit entails a thorough assessment of the blockchain application’s smart contracts. The fundamental approach to conducting an audit is generally consistent across various audit service providers. The smart contract audit process involves the following steps:

Requirement gathering

The previously mentioned variables aid in defining the audit scope, intended business behavior, overall architecture, and project objectives. Developers must ensure that auditors are granted access to essential documents such as the business requirement document, technical specification document, project’s whitepaper/yellow paper, smart contract code through GitHub commits, and other relevant materials.

Unit testing

During the auditing process, the developer executes unit tests to verify that the smart contract operates according to its intended functionality. At this stage, developers utilize auditing tools and testnet environments to ensure that unit testing comprehensively covers the highest potential risks.

Manual auditing

This is the auditing process’s most crucial aspect. The code is scanned by the auditor for vulnerabilities on a line-by-line basis. Subsequently, the developer proceeds with the deployment of auditing tools such as Mythril, Slither, MythX, Scribble, and other similar tools to conduct a comprehensive examination of the code.

Developers receive recommendations from auditors regarding modifications to smart contracts for addressing vulnerabilities and optimizing code.

Initial reporting

After conducting both manual and automated audits, a preliminary report is generated that outlines identified issues and their corresponding levels of severity. In addition, the security team furnishes clarifications regarding the smart contract’s issues and their corresponding levels of severity.

Code refactoring

At this stage, developers work closely with auditors to address issues identified in the initial report by modifying the code accordingly. It is ideal for developers to address every bug, regardless of its severity level. However, it is recommended to prioritize the resolution of high and medium-severity issues first.

Final report

Refactor the postcode and have auditors perform another scan on the smart contract to verify optimal code functionality.

How Long Does a Contract Audit Take?

The duration required to conduct a security audit of a smart contract is contingent upon the scope and intricacy of the code. Typically, a development team can generate a detailed report in a matter of days. However, larger applications may require more time to be audited. For the successful implementation of your blockchain application, it is imperative to allocate sufficient time for a comprehensive security audit.

How Much Does It Cost?

The smart contract audit firms determine the cost. Typically, the overall price ranges from $5,000 to $15,000. In certain edge cases, the cost could exceed the standard amount. Upon completion of the audit, the auditing firm will furnish an audit report that outlines the code’s defects and suggests enhancements to strengthen the application’s overall security.

Conclusion

Smart contract audits are now a routine procedure for investors and users. If a feature is ubiquitous across all projects, it no longer holds value as a distinguishing factor. It is crucial for developers to read the audit themselves. Providing comments and indicating the level of severity for potential issues can be advantageous, even for those without technical expertise.