Why Automotive Developers Shouldn't Overlook Application Fuzzing

As a product security professional, you likely know that protocol fuzzing is important. Protocols are the foundation of communication between networked devices, and performing protocol fuzz testing ensures that the protocol can handle unexpected and potentially harmful data. 

You might not think about application fuzzing as much, but it is just as important since it addresses different layers of potential vulnerabilities within a system. This blog post will explore why application fuzzing is important and how it can complement protocol fuzzing in automotive development.

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What is protocol fuzzing?

Protocol fuzzing primarily targets the communication interfaces and network protocols used by ECUs. It involves sending malformed or unexpected inputs to these interfaces to uncover vulnerabilities such as incorrect parsing of messages, buffer overflows, and improper error handling. While protocol fuzzing is effective at identifying issues at the surface level, it does not delve into the internal logic and functionality of the software.

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What is application fuzzing?

Application fuzzing, on the other hand, focuses on testing the internal application code. It generates random, semi-random, or edge-case inputs to feed into the software functions, aiming to uncover bugs, memory leaks, and other vulnerabilities within the code itself. By integrating application fuzzing into your testing strategy, you can achieve deeper coverage and identify issues that protocol fuzzing alone might miss.

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4 Benefits of Application Fuzzing

1. Increased Security and Reliability

Vulnerabilities within the application are often deep within the application logic and can only be found by fuzzing the application. If found by attackers, these vulnerabilities can lead to severe security breaches if left unaddressed, as they are often unknown vulnerabilities that can lead to zero day exploits. Application fuzzing improves the overall security of your software by testing it in the same way that attackers do. 

A prime example of the necessity for thorough fuzz testing is the infamous Jeep Cherokee hack in 2015. Security researchers Charlie Miller and Chris Valasek demonstrated a remote exploit that allowed them to control various functions of a Jeep Cherokee, including steering, brakes, and transmission. This exploit was possible due to vulnerabilities in the software running on the vehicle's ECUs. Application fuzzing could have helped identify these vulnerabilities before the software was deployed, potentially preventing the attack.

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2. Improved Software Quality

Including application fuzzing in security testing contributes to a more robust and resilient codebase. It helps developers identify and fix bugs early in the development process, leading to cleaner, more maintainable code and reducing the likelihood of issues arising in the production environment. 

It also improves user experience. Application fuzzing simulates unexpected inputs and interactions to test that the vehicle's software will operate reliably under unpredictable conditions. As a result, drivers benefit from more secure and stable in-car systems, which translate to improved safety features, seamless infotainment functionality, and overall smoother vehicle performance. This increased software quality helps build trust and satisfaction among users by minimizing the risk of software-related issues on the road.

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3. Cost-Effectiveness

Detecting and fixing bugs during development is significantly cheaper than addressing them post-deployment. A study by the National Institute of Standards and Technology (NIST) found that the cost to fix a defect identified after software is deployed can exceed 30x the cost of fixing that same defect during development. By integrating application fuzzing into your CI/CD pipeline, you can continuously test your software and catch issues early, saving time and resources in the long run.

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4.  Compliance and Standards

In the automotive industry, compliance with safety and cybersecurity standards is crucial. Standards such as ISO 26262 for functional safety and ISO 21434 for cybersecurity emphasize the importance of thorough testing methodologies. Application fuzzing aligns with these standards by providing a systematic approach to uncovering and addressing vulnerabilities within the software.

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How to Implement Application Fuzzing 

There are several mature and user-friendly application fuzzing tools available that can be easily integrated into your development workflow. Tools like AFL, LibFuzzer, and Peach Fuzzer are widely used in the industry and support a range of programming languages and environments.

The easiest way to fuzz your application is to use an automated solution that integrates into your CI/CD pipeline, ensuring continuous testing as part of the development process. This approach allows you to catch issues early and often, maintaining a high standard of code quality and security.

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Conclusion

Application fuzzing complements protocol fuzzing to find and fix issues both in how software communicates and how it runs. This dual approach ensures your system is stronger and safer, ultimately ensuring the safety and satisfaction of your customers.

By investing in application security, you demonstrate a commitment to quality, which can enhance your brand reputation and build trust with both customers and industry partners, help you stay ahead of regulatory requirements, and avoid potential costly recalls or safety issues.

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Mayhem for Application Fuzzing

To learn more about how application fuzzing can benefit your organization, consider exploring Mayhem's fuzzing solutions. Our cutting-edge technology is designed to uncover vulnerabilities and ensure that your application performs flawlessly under real-world conditions. Schedule a demo with our team to see firsthand how Mayhem can help you find and resolve vulnerabilities sooner, save on development costs, and make your software development process more efficient.

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