Embedded systems are a part of modern technology that most people often overlook. But they play an essential role in almost every aspect of the digital world. Indeed, it would be impossible to visualize modern life without embedded systems. That hybrid vehicle that brought you to work runs on an embedded system, and so does the microwave oven you used to reheat lunch. Your smartphone will not function without an embedded system, and neither will your office elevator nor the traffic light outside your home.
The uses of embedded systems seem infinite, but so are the threats that endanger them. As technology progresses, design engineers are creating smaller and smarter pieces. However, as they add more functionalities and new features into embedded systems, they risk crowding out basic security measures, making embedded devices susceptible to attacks. The alarming thing is, it only takes one vulnerable spot for a hacker to exploit the entire system.
The threats surrounding embedded systems come in different forms – spying and tampering, hacking, man-in-the-middle attacks, memory data errors, DNS poisoning, signal jamming, brute-forcing access. From toasters to printers to play stations and vehicle controls, embedded devices have been the target of well-structured attacks for many years. Such attacks are not only financially detrimental to a business but could also potentially lead to human injury.
Most embedded systems use password protection and encryption protocols that include Secure Shell (SSH) or Secure Socket Layer (SSL) to combat threats. However, as attackers get more familiar with the systems, these protective measures become inadequate to make the devices secure.
In this article, we analyse what makes an embedded system safe. We touch on five of the most crucial design principles and best practices that keep malicious third parties from accessing, attacking, or tampering with embedded systems.
Data-at-Rest Protection
Data can either be in motion or at rest. Any data that is not moving from a device to another or network to another is data-at-rest. It includes information, applications, configurations stored on a hard drive, flash drive, or some other media, such as rest microcontrollers or microprocessors in embedded devices. Typically, a firewall or anti-virus software protects static data. However, to effectively deter attackers from getting into the system illegally, you need to install extra defence layers, including encryption, password-protected access, and multi-factor authentication.
Utilising industry-standard encryption algorithms such as Advanced Encryption Standard (AES), Rivest–Shamir–Adleman (RSA), Error Correction Code (ECC), or Secure Hash Algorithm (SHA) is an effective way to protect static data. You can secure cryptographic keys by obfuscating the codes or making them unclear so attackers cannot understand them.
With system breaches increasingly becoming rampant, companies must understand the potential threats of the digital world. Taking an online training course in cyber security helps businesses effectively combat any looming dangers to their system.
Authenticated and Secure Boot
When you power-on an embedded system, you want to make sure that the first code that runs on the device is authentic and legitimate. Even if the system is booting successfully, it is possible that some malware has infiltrated it, and the rest of the software is trusting the malicious code. For this reason, you must invest in a secure boot feature. It allows a microprocessor to validate the crypto key, the firmware location, and other essential software aspects.
Take note that numerous vulnerabilities exist in system boot sequences. To enhance the secure boot feature, be sure to utilize a processor’s trusted execution environment option. It creates a safe zone to store firmware and ignore threats from the rest of the system. More importantly, use only a well-designed secure boot technology such as UEFI Secure Boot, Grub Secure Boot, Intel TXT or tboot, and uboot.
Hardware Resource Partitioning
If the software has unlimited access to the hardware’s every component, cybercriminals can use the same to launch malicious activities on the rest of the system. It could compromise the integrity of the entire embedded device and result in disastrous consequences.
Every section of the system should be protected separately. Hardware resource partitioning constrains software access to specific hardware components such as CPU cores, cache, and memory. It provides necessary security measures by isolating and separating the different areas of the system. Therefore, if one application is under attack, it cannot spread to other zones. Compartmentalization averts the disruption of the whole system. In other words, partitioning prevents corrupted components from directly or indirectly affecting other parts of a device.
Secure Software Development and Build Options
The protection of embedded systems starts from the earliest level of their development. At the designing and building stages of the software, most design engineers prioritize implementing security measures into the system to guarantee a successful Software Development Cycle (SDLC). Integrating protection protocols during software development helps identify and mitigate vulnerabilities early on. It results in a more reliable system and reduces expensive fixes later due to unforeseen security gaps.
However, the system is not absolutely secure unless designers conduct security assessments during all phases of the development cycle. Comprehensive security assurance measures that include architecture analysis, code review, penetration testing, and threat modelling should be in place.
Furthermore, developing a secure system is a challenging process and should be handled by trained experts. With that said, the jobs for competent embedded software engineers to design well-protected software.
Integrity Monitoring and Auditing
You cannot counter cyber-attacks if you have no idea your system is being breached. Attackers know this and take advantage of it. Indeed, they hit when you least expect it. That is why you need integrity monitoring and auditing to detect whenever attackers breach or compromise the system. Integrity monitoring validates your files by comparing them to a trusted baseline and generates alerts if the data were altered, compromised, or modified without authorization. In case you are unable to prevent the breach, you will at least discover how they manipulated the system and which component they compromised.
Aside from detecting illegal activities and pointing out unintended changes in the system, auditing enables businesses to comply with regulatory mandates. In the United States, the Health Insurance Portability and Accountability Act and the Federal Information Security Management Act (FISMA) require organisations to comply with integrity monitoring and auditing. The equivalent of this legislation in the UK is the Data Protection Act (DPA). Other regulatory mandates that require compliance include Sarbanes-Oxley Act (SOX), Payment Card Industry Data Security Standard (PCI DSS), and Financial Services and Markets Act 2000 (FISMA).
