490
B. Russell
Defending against firmware modification is possible using techniques such as
tamper resistance and firmware integrity protections. To sufficiently guard against
the myriad attacks possible against IoT devices though, a layered security approach
must be implemented. In the following sections we describe techniques that can be
used to secure IoT devices at the edge. We categorize these recommendations based
on the need for:
• A Hardware Security Element that Supports Trusted Operations
• Configure a Secure Real-Time Operating System
• Implement Physical Security Controls
• Deploy Confidentiality Protections
• Implement Strong Authentication and Access Controls
• Harden Network Services
• Implement Logging
• Integrate Framework Security
10.4.1 Use a Hardware Security Element to Support Trusted
Operations
The cyber security posture of an edge machine begins with the security features
provided at the platform layer. This includes a hardware security module, a secure
real-time operating system, and physical protections against tamper. Many hardware
security features were previously only found in hardware security modules (HSMs);
however, there are many products on the market today that meet strict size, weight,
and power requirements while still offering secure hardware features. MCUs on the
market today come from vendors such as FreeScale, Atmel, NXP, microchip, and ST
Microelectronics. Security features provided by a hardware security module should
include:
Trusted Boot A cryptographic boot loader can be implemented to validate the
integrity of the operating system prior to boot. The trusted boot process initializes
the trusted execution environment. The process involves validation of signed hashes
applied to operating system components including the kernel and system partition.
A hardware root of trust applies the signature of the hash which is then verified prior
to loading.
Trusted Execution Environment A hardware root of trust can be used to segregate
untrusted and trusted portions of an IoT machine. Trusted applications can be
installed that are validated prior to allowing to run on the machine. The Trusted
Computing Group (TCG) and others have worked on adapting TEE specifications
to the IoT environment. The TEE incorporates hardware capabilities of the machine
including storage, peripheral access, and the secure element. The TEE also incorporates trusted OS drivers and exposes a client API that can be used by untrusted
applications to interact with trusted components [21].
B. Russell
Defending against firmware modification is possible using techniques such as
tamper resistance and firmware integrity protections. To sufficiently guard against
the myriad attacks possible against IoT devices though, a layered security approach
must be implemented. In the following sections we describe techniques that can be
used to secure IoT devices at the edge. We categorize these recommendations based
on the need for:
• A Hardware Security Element that Supports Trusted Operations
• Configure a Secure Real-Time Operating System
• Implement Physical Security Controls
• Deploy Confidentiality Protections
• Implement Strong Authentication and Access Controls
• Harden Network Services
• Implement Logging
• Integrate Framework Security
10.4.1 Use a Hardware Security Element to Support Trusted
Operations
The cyber security posture of an edge machine begins with the security features
provided at the platform layer. This includes a hardware security module, a secure
real-time operating system, and physical protections against tamper. Many hardware
security features were previously only found in hardware security modules (HSMs);
however, there are many products on the market today that meet strict size, weight,
and power requirements while still offering secure hardware features. MCUs on the
market today come from vendors such as FreeScale, Atmel, NXP, microchip, and ST
Microelectronics. Security features provided by a hardware security module should
include:
Trusted Boot A cryptographic boot loader can be implemented to validate the
integrity of the operating system prior to boot. The trusted boot process initializes
the trusted execution environment. The process involves validation of signed hashes
applied to operating system components including the kernel and system partition.
A hardware root of trust applies the signature of the hash which is then verified prior
to loading.
Trusted Execution Environment A hardware root of trust can be used to segregate
untrusted and trusted portions of an IoT machine. Trusted applications can be
installed that are validated prior to allowing to run on the machine. The Trusted
Computing Group (TCG) and others have worked on adapting TEE specifications
to the IoT environment. The TEE incorporates hardware capabilities of the machine
including storage, peripheral access, and the secure element. The TEE also incorporates trusted OS drivers and exposes a client API that can be used by untrusted
applications to interact with trusted components [21].