7 Must-Know Web3 Penetration Testing Techniques to Secure Your Smart Contracts

The rise of the crypto industry, more adoption, the entry of new users, and complex applications have attracted hackers who are always looking to exploit the space. The attackers keep on scouting the on-chain contracts for any exposed vulnerability and take advantage of it.

These vulnerabilities lead to huge financial losses, loss of community trust, and collapse of the protocol. Considering all these facts, it is more important than ever to create a pre-deployment pipeline of the smart contracts and off-chain infrastructure, which includes robust testing and auditing of the code.

This blog explores certain Penetration Testing techniques. These techniques are essential to proactively identify and mitigate any vulnerabilities around smart contracts and the app infrastructure.

Here are 7 must-know Web3 penetration testing techniques to help secure your smart contracts:

1. Information Gathering (OSINT)

This is the initial stage of pentesting, as this phase is used to gather information from crawling through the whole web architecture of the application. Here are some things to target while performing OSINT.

• Web Architecture: Understand the front-end and the underlying tech stack, web server configurations, and API integrations involved to process a request.
• Information Leakage: Identify publicly accessible information that could reveal any sensitive details that can be leveraged to perform harm to the application. This might include exposed API keys, configuration files, or logs.
• Web Service Integration: Analyze how the protocol or app interacts with the centralized web services to identify potential weaknesses in these integrations.
• Off-Chain Infrastructure: This includes gathering information about the underlying servers, databases, and cloud services that support the application.

Tools like DNSenum, Dirbuster can be of help here to explore the web directories and conduct a deep analysis.
 

2. Automated Pentesting

Leveraging automated tools becomes essential while dealing with huge codebases, as it detects some low-hanging fruit or common vulnerabilities. While specialized tools or processes exist for smart contracts, like Fuzzing, the same is true for off-chain components.

Automated Pentesting Tools look for security weaknesses in the servers, network devices, and web applications. It also analyzes if the website is protected from attacks like SQL injection and cross-site scripting.

It also helps identify misconfiguration, outdated software, and certain known vulnerabilities in the web servers, APIs, and other parts of the infrastructure.

Tools like Nessus, Acunetix, Nuclei (Open-Source Vulnerability Scanner), and Nabbu can be utilized for automated vulnerability tests.
 

3. Platform and Configuration Testing

This technique focuses on the web servers, databases, cloud services, and any other infrastructure components to ensure they are functioning properly. Key areas this technique focuses on:

• Security Overview: Verify that the system is configured according to the security best practices, with unnecessary services disabled and strong access controls in place.
• Patch Management: Ensures that all the software components are up-to-date with the latest security patches to mitigate known vulnerabilities.
• Validating Access Controls: Validate that access to sensitive resources is limited and configured based on the principle of least privilege(PoLP).
• Network Segmentation: Ensure that the network architecture follows the best security practices and has proper isolation between different components of the infrastructure.

4. Business Logic and Client Side Testing

Protocols often involve complex client-side logic with business logic implemented both on-chain via smart contracts and off-chain. This testing technique focuses on mitigating the following vulnerabilities:

• Client-Side Vulnerabilities: Identify vulnerabilities around the frontend architectures, such as XSS (Cross-Site Scripting) and insecure handling of local storage. Tools like browser developer consoles and manual code review can be useful here.
• Business Logic Flaws: This process involves testing the application’s core functionality or the business logic to identify any logical errors that could be leveraged to exploit the system. This often involves creating specific test cases to simulate user interactions. These custom scripts test the infrastructure from the user’s perspective.
• API Security Vulnerabilities: Accessing the security of the APIs involves validating any problems around transmission, authentication, authorization, and data exchange. Tools like Postman are ideal for testing API endpoints.

5. Error Handling and Data Validation

A robust architecture includes proper error handling, as it can leak sensitive information, while inadequate data validation can lead to injection attacks. The testing technique mainly focuses on:

• Error Message Analysis: Examining error messages to determine if they disclose any sensitive information about the application’s internal architecture or working.
• Input Fuzzing: Use a random array of data to identify vulnerabilities around improper data handling.
• Edge Cases Testing: Test the application’s behavior with extreme or edge-case inputs.
• Format String Vulnerabilities: Help in identifying potential flaws where user-applied input is used directly in formatting or updating the function execution.

Tools like Burp Suite can be utilized here to manipulate and intercept requests.
 

6. Encryption and Secure Data Handling

It is important to ensure that the proper implementation and strength testing are done for the encryption mechanisms adopted in the application. This technique accesses the following:

• Transport Layer Security (TLS/SSL): Verifying that secure communication protocols are used for all the sensitive data transmission between the client and server.
• Data-at-Rest Encryption: Analyzing the encryption mechanisms used to protect sensitive data stored in databases or file systems. This ensures that data which is stored in servers is protected from any unauthorized access.
• Key Management: Analyzing and ensuring how encryption keys are generated, stored, and managed. This part is important, as if the attacker got access to the keys, they would gain access to the data even if proper encryption techniques are adopted.
• Cryptographic Algorithm Strength: Ensure that the strong and up-to-date cryptographic algorithms are utilized.

7. Smart Contract Specific Testing

While the other techniques are there to test the broader infrastructure of the application, this one is focused primarily on the Smart Contract Testing. Key techniques include:

• Static Code Analysis: Use tools like Slither and Mythril to analyze the solidity code for common vulnerabilities like integer overflows/underflows, reentrancy, and more without executing the contract.
• Dynamic Code Analysis: This involves deploying the contract to the local testnet using Foundry or Hardhat. Once deployed, contracts can be tested for business logic, access control, and unexpected interactions.
• Fuzz Testing: It involves generating a large amount of random inputs to detect any unexpected behavior and edge cases in the smart contracts. Foundry does provide Fuzz Testing features.
• Formal Verification: Utilize tools like the K Framework to ensure the correctness of the smart contracts mathematically.
• Gas Analysis: Analyze the gas consumption of the smart contract functions to identify Denial of Service (DOS) vulnerabilities and areas for optimization.

Ultimate List of Tools that can be utilized for efficient Pentesting

• Burp Suite: An essential web application security testing suite for intercepting and manipulating HTTP/S traffic.
• DNSenum: A tool for DNS reconnaissance.
• Dirbuster: A web directory brute-forcing tool.
• SQLMap: An automated SQL injection testing tool (relevant for off-chain databases).
• Acunetix: An automated web application security scanner.
• Nuclei: Another open-source web application security scanner.
• Nabbu: A web application vulnerability scanner.
• Nmap: A network scanning and service discovery tool.
• Metasploit: A powerful framework for penetration testing and exploitation.
• Horusec: An open-source security scanner for identifying vulnerabilities in code.
• Postman: A tool for API testing and development.
• Nessus: A comprehensive vulnerability scanner.
• Slither: A static analysis framework for Solidity.
• Mythril: A security analysis tool for EVM bytecode.
• Hardhat: An Ethereum development environment for compiling, deploying, testing, and debugging smart contracts.
• Foundry: A blazing-fast, portable, and modular toolkit for Ethereum application development.
• K Framework: A formal verification framework.
• Selenium: A tool for automating web browser interactions (useful for client-side testing).

Conclusion

Attacks on a protocol are not just limited to smart contracts but expand to the whole infrastructure. It is more important than ever to test your whole infrastructure, which includes the frontend, web servers, databases, backend services, smart contracts, and more, depending on the protocol’s architecture.

Robust Testing and Auditing of the smart contracts and the core infrastructure is a crucial process that needs to be included in the pre-deployment pipeline, considering the immutable nature of the blockchain.

The blog summarizes different Web3 penetration techniques that can be adopted while testing a protocol’s infrastructure and smart contracts.