ISO SAE 21434: Cybersecurity of Road Vehicles

Mayhem Team
February 17, 2022
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Automotive cyber attacks are a growing concern for the automotive industry. Malicious actors can exploit vulnerabilities in vehicles to access their systems, causing chaos, disruption, and safety concerns.

Some of the most common attacks against cars include remote access exploits where bad actors can take control of a vehicle's systems remotely, Wi-Fi hacks that enable bad hackers to gain access to internal networks via the Wi-Fi system, vehicle malware, and Bluetooth hacks.

The ISO SAE 21434 standard provides automakers and other stakeholders in the automotive industry with guidance on how to help protect road vehicles from cyberattacks, including those mentioned above. This post will broadly cover what ISO SAE 21434 is, who it directly affects, and how interested parties can comply.

What is ISO SAE 21434?

ISO SAE 21434 is a standard that guides the protection of road vehicles from cyberattacks. It was developed by the International Organization for Standardization (ISO) and the Society of Automotive Engineers (SAE). The standard covers various topics related to vehicle cybersecurity, including risk assessment, security controls, and incident response. It also includes best practices for protecting vehicles from cyber threats, such as malware and ransomware.

ISO SAE 21434 is a valuable resource for automakers and other stakeholders in the automotive industry who are looking to keep their products safe from malicious attacks. The standard helps organizations identify and mitigate potential vulnerabilities in their vehicles, which hackers could exploit. By following the guidance in ISO SAE 21434, automakers can implement cybersecurity solutions tailored to their unique vehicle systems.

ISO SAE 21434 establishes a risk-based approach for managing cybersecurity risk across the entire life cycle of vehicles. It divides vehicles into five functional safety levels, based on what critical functions they perform. The function level determines which security controls are defined in ISO SAE 21434.

 Each section of ISO SAE 21434 is structured around these five functional safety levels. The standard separates the overall process of assessing and managing risks into seven phases covering core topics such as risk management, threat modeling, vulnerability management, and incident response.

Who benefits from ISO SAE 21434?

How automakers benefits from ISO SAE 21434

ISO 21434 benefits nearly all parties involved in the automotive industry, including automakers, suppliers, and consumers when it comes to managing cybersecurity risk.


ISO SAE 21434 provides vehicle manufacturers and automotive engineers with requirements and a comprehensive framework for protecting vehicles from cyberattacks. The standard helps automakers identify and mitigate risks and develop and implement security controls.

The standard also helps automakers to respond to cybersecurity incidents. ISO 21434 includes best practices for safeguarding against malware and ransomware, which are among the most common threats to automotive cybersecurity.


ISO SAE 21434 also benefits suppliers of automotive components and systems. The standard provides guidelines for securing these components and systems from cyber threats. This helps suppliers to meet the high-security standards demanded by automakers.


ISO SAE 21434 also benefits consumers, who can be assured that the cars they buy conform to the highest cybersecurity standards.

How to comply with ISO SAE 21434

How to comply with ISO SAE 21434

If you are within the automotive sector and are looking to comply with ISO SAE 21434, there are a few key things you need to know. The standard provides guidance on the protection of road vehicles from cyberattacks, so it is essential to adopt the necessary security controls to keep your fleet safe.

Additionally, risk assessment is a critical part of compliance with ISO SAE 21434. You need to understand the potential risks posed by cyber threats and take steps to mitigate those risks.

Finally, incident response is important for dealing with any attacks that may occur. Having a plan in place for responding to cyber incidents can help minimize the damage caused by an attack.


Fuzzing is an important part of cybersecurity and threat analysis, and ISO 21434 specifically calls fuzz testing out in section 10.4 regarding recommended testing methods. 

In accordance with ISO 21343, and past history in automotive hacks, ForAllSecure highly recommends fuzz testing to harden road vehicle E/E (electrical and electronic) systems, their components, and interfaces. By adopting fuzz testing in the automotive component development and verification phases, one can assure that critical weaknesses and vulnerabilities are caught early on, leaving attackers unable to exploit the systems.


ISO SAE 21434 is an important standard for automakers and suppliers to stay on top of. In this blog post, we've provided you with an overview of ISO SAE 21434 as well as how it benefits automakers, suppliers, and consumers alike. If you are looking to comply with ISO SAE 21434 or want to know how our Mayhem fuzzing solution can be integrated into your testing process, be sure to contact us! Our team will guide you through your options so that you can keep your fleet safe while avoiding costly mistakes in compliance efforts.

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