Embedded systems are everywhere – from coffee machines to industrial control systems. But they are often poorly secured, which makes them the perfect target for attackers. In this article, you will find out why embedded security, a specialist area of cyber security, is so important, what attacks are a threat and, above all, how you can practically secure your systems.
Why is security in embedded systems so critical?
An embedded system is often not a fully-fledged computer, but a specialized unit with limited resources. However, this is precisely what makes them so vulnerable:
- Long lifecycles – Many embedded systems are in use for ten or more years. Security updates? Often not available.
- Physical access – Embedded devices are often located in insecure environments. Attackers can manipulate them directly.
- Low computing power – Many systems do not have the CPU power for complex cryptography.
- Lack of standards – Embedded security is complex and there are often no clear security guidelines.
In addition, cyber attacks on embedded systems often have a real impact: Tampered medical devices, hacked industrial controllers or exploited IoT devices in botnets are no longer science fiction.
Typical attacks on embedded systems
Before we get to the defensive measures, a brief look at the most common attacks:
1. firmware extraction
Attackers try to read the firmware of a device. Why? Because they can use it to analyze vulnerabilities or even import their own malicious version.
Practical example: Many microcontrollers have a debugging interface (JTAG or SWD). If this is not secured, anyone can read the firmware with just a few tools (e.g. OpenOCD, J-Link).
Solution:
- Deactivate debug interfaces or only activate them with authentication
- Use secure boot to only allow signed firmware
- Use firmware encryption
2. Side-Channel Attacks
Attackers use physical measurements to extract secret data. Examples include voltage or electromagnetic measurements that allow conclusions to be drawn about cryptographic keys.
Practical example: An attacker measures the power consumption of a smart card controller when decrypting a message. Based on the fluctuations, he can reconstruct the private key.
Solution:
- Constant power consumption through hardware-level masking
- Use noise sources or active shielding
- Observe side-channel resistance in cryptography implementations
3. Manipulation of the Boot process
If the boot process is not secured, an attacker can install their own modified firmware.
Solution:
- Secure boot with cryptographically signed firmware
- Use hardware protection mechanisms such as TrustZone (ARM) or TPM
4. Attacks on communication
Many embedded systems communicate via UART, SPI, I2C or CAN bus. These protocols are often unencrypted and vulnerable to man-in-the-middle attacks.
Solution:
- Encryption with TLS or DTLS (if possible)
- Authentication of the communication partners
- Physical protection of the bus lines
5. Code Injection & Buffer Overflows
As with regular computer systems, memory overflows are also a major problem with embedded systems. An attacker can execute arbitrary code and take control.
Solution:
- Secure programming languages (Rust, Ada) instead of C/C++
- Secure coding guideline
Stack canaries and ASLR (if supported by the system) - Fuzzing tests during development
Praktische Sicherheitsstrategien für Embedded Systems
Now it’s getting concrete. Here are proven methods for making your embedded systems more secure:
1. Hard protection of the firmware
Use Secure Boot to ensure that only signed software is executed. Many modern microcontrollers support this, but it must be configured correctly.
2. Secure updates & patch management
If your system can receive updates, then only via signed and encrypted firmware updates.
3. Minimal attack surface
Every open debug interface, every activated feature is a potential vulnerability. Switch off everything that is not absolutely necessary!
4. Use Hardware Security Module (HSM) or TPM
If your embedded system performs cryptographic operations, use an HSM or a Trusted Platform Module (TPM). This protects private keys against physical attacks.
5. Secure memory and peripherals
If possible, use Memory Protection Units (MPUs) or TrustZone to protect critical memory areas. This prevents errors in one application from compromising the entire system.
6. Enforce secure communication
If your embedded system communicates wirelessly or over a network, use the strongest possible encryption and secure protocols:
- TLS/DTLS instead of unencrypted TCP/UDP
- WPA3 instead of open WLAN networks
- Secure key management
7. Do not forget physical security
- Locks for enclosures to prevent tampering
- Sensors for sabotage attempts
- Epoxy resin or special protective layers on chips to make attacks more difficult
Conclusion
Security is not an option, but a must – regardless of whether you are developing a small IoT device or securing an industrial control system. Important measures are:
- Firmware protection (secure boot, disable debugging)
- Secure updates (signed, encrypted updates)
- Minimize attack surface (deactivate unnecessary interfaces)
- Encrypted communication (TLS, secure key management)
- Hardware protection (MPUs, TrustZone, TPM)
Implement as many of these measures as possible – then you will sleep more soundly at night and your embedded systems will remain secure.
It is advisable to have professional penetration tests carried out to ensure the effectiveness of your embedded system. To find a suitable provider, we recommend visiting our cyber security marketplace.
