How to Make Your Firmware Secure?

Embedded system security can hardly be overestimated by business owners and end users.

17:19 09 May 2023

Embedded system security can hardly be overestimated by business owners and end users. Imagine having an untrustworthy device in your car or production facility where compromised security will have various negative effects. 

Laying the groundwork for a secure embedded system starts with following security measures during firmware development https://lembergsolutions.com/firmware-development. Secure firmware also ensures an excellent reputation among end users and stakeholders. Dive in and discover the tips for secure firmware development that will help you make your product safe and reliable.

What is firmware?

Firmware is an integral part of the hardware that runs the programs on the devices and embedded systems. Firmware acts as an instructor that launches hardware, helps different devices communicate with each other (which is especially important in IoT systems), and ensures program execution. No hardware can ever operate without firmware. Embedded engineers regularly update the firmware to enable stable hardware performance and maintain a device's security. 

Firmware architecture development process

To ensure the security of your firmware solution, you should make sure that a firmware architecture development process is set up properly. If you follow the steps below, your firmware will be robust and reliable.

Identify the requirements

A well-thought list of requirements helps to build a system that matches your idea and meets end users' needs. Before developing your firmware, make sure you know all the functions your future system will perform. You should know what features it will include and how it will operate. 

There are two requirements to your firmware requirements — they should be precise and testable. Make your requirements as clear as possible to ensure you don't stray from an initial project idea. The requirements should be defined in a way that enables further testing. All in all, you need to check if the requirements were met.

Organize your deadlines 

In firmware development, you should better treat soft deadlines as hard deadlines. Try to set fixed dates for each feature creation. However, don't forget to include time for feature testing and fixes.

Plan the system’s scale

When developing a solid firmware architecture, you should take into account the future changes that can be implemented into your solution. While building a specific device, brainstorm with your team what features can potentially be added to a product and how to avoid major downtime when new features are introduced.

Key tips to secure your firmware

Input validation

Every embedded system receives input data, and engineers need to take care of the system security during the firmware development stage. Include input validation into your firmware so that any time an untrusted source interacts with a system, it starts checking the received data. Input validation applies to hardware connected to a system as well as Internet sources. 

Make sure that your firmware verifies configuration data before modifying a system's operation. Besides, a system should check the metadata coming from updates and other devices or hardware components.

Safe memory

One of the vulnerabilities embedded engineers should avoid is a buffer overflow that exposes a system to cyberattacks. When the data in the buffer surpasses the storage capacity, an embedded system becomes unsafe and can be easily hacked. 

Take care of your system's response to memory allocation. If you don't develop proper processes that regulate memory allocation, a system may crash and become a target for cyber attackers. For instance, if your firmware doesn't block access to executed code and deallocated data, the system will break down. Moreover, your system's memory can be compromised if you neglect race condition. In this case, a system will perform several operations in the wrong order, leading to more vulnerabilities in the code. You can also use memory-safe language, which doesn't require multiple additional steps to secure a system's memory.

Source control

Managing your code is paramount for secure firmware development. If you can't keep track of the modifications you implement in the code, your firmware becomes accessible for malicious attacks. You should always audit and document code adjustments by supervising commits, who implements them, and why they have been introduced. One of the ways to maintain reliable source control is to follow CI/CD practices. This way, you will ensure regular code review, testing, and bug fixing, which leads to more refined firmware.

Code reviews

Include a code review practice into your firmware development routine. Encourage your team to reexamine the code in terms of its security, especially before updating the firmware and before the product launch. Search for new solutions to make your firmware safer since it's always better to recognize the pitfalls before the product enters the market. 

Third-party software 

Ready-made solutions are always of great help when it comes to firmware development. The popularity of open source technologies made the use of third-party libraries a common thing among embedded engineers. However, third-party resources should still be used carefully and with certain precautions to avoid compromising security. Don't forget to check how a third-party resource of your choice maintains security and keep record of the code you extract from a third-party library. 

All in all, the security of your firmware boils down to regular code audits and documentation, safe memory, and careful use of third-party software. The more precautions you take during the firmware development stage, the fewer issues you will fix after the product release. Besides, firmware security directly affects a product's reputation among end users. Following all our tips will help you make your firmware protected from malicious attacks and build a trustworthy embedded system.