🤮 Silicon Labs Key Management – **The Weaknesses**

Products & Technology XIAO
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Hi there,

SO … Allot of discussion on here and many other forums are buzzing about Back doors, side doors , who’s doing what, Having done some research in the field the real progress is done Physically. anyone says different doesn’t know JACK! :microscope:

Take for example the Xiao Brain Silicon, Espressif, Nordic, SIL and others. ALbeit some of this silicon is made in the same TSMC facilities.

Silicon Labs

does offer secure key storage and cryptographic functionality, but there are some key differences and potential vulnerabilities compared to Nordic’s approach. Here’s the breakdown:

1. Limited Hardware-Based Key Protection (Especially on Lower-End Devices)

  • Not all SIL devices include dedicated key management units (KMUs) like the Cryptocell-310 on nRF52840.
  • Lower-end or budget devices may rely more on software-based key handling, which is inherently more vulnerable than hardware-protected keys.

2. Simplicity Over Security in Many Cases (Due to Compatibility)

  • SIL focuses heavily on compatibility with their legacy SDKs and modules.
  • This often means simpler implementations of cryptographic features that prioritize ease of use over strong security.
  • While Secure Boot and Encrypted Bootloaders are available, they don’t emphasize on-device key generation or derived keys nearly as much as Nordic’s solution.

3. Secure Vault Implementation (More Recent but Not Universal)

  • SIL introduced Secure Vault (e.g., Series 2 devices), which does add hardware-based key storage features.
  • However, older or cheaper devices rely on Flash-based storage, which is more susceptible to attacks.
  • Even with Secure Vault, if the firmware is designed without proper key management in mind, vulnerabilities can occur.

4. Insufficient Key Derivation Mechanisms (Compared to Nordic’s Cryptocell-310)

  • Unlike Nordic’s on-device key derivation which uses device-unique identifiers (FICR, etc.), SIL often relies on simpler mechanisms.
  • This makes key extraction theoretically easier for attackers who gain physical access to the device.

5. Inconsistent Support Across Products

  • Not all SIL MCUs have robust key protection features enabled by default, while Nordic’s Cryptocell-310 is standard on nRF52840.
  • It’s more a case of “pay more to get proper security” with SIL, while Nordic offers it out-of-the-box.

Nordic’s Cryptocell-310 is an integrated hardware solution designed for secure key handling and on-device key derivation. SIL’s attempts at implementing secure key management are scattershot and inconsistent across their product line.

There is more , but you get the Jist… Choose wisely , but implement PROPERLY :v:

GL :slight_smile: PJ :+1:

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I’ll offer this…

:mag: Documented Security Vulnerabilities in Silicon Labs’ Gecko Platform

A notable security issue was identified in the Gecko Bootloader of Silicon Labs’ platform, specifically within the Over-the-Air (OTA) update parser. This vulnerability could potentially allow unauthorized code execution during the firmware update process. The detailed analysis and implications of this vulnerability are discussed in the following blog post:​Quarkslab’s blog+1Mouser+1

  • Breaking Secure Boot on the Silicon Labs Gecko Platform: This article presents an in-depth examination of the vulnerability found in the Gecko Bootloader’s OTA parser, highlighting potential risks associated with firmware updates. ​Quarkslab’s blog

Responded with …
Silicon Labs has implemented various methods for secure key storage, including the use of Physically Unclonable Functions (PUFs) to generate device-specific keys. However, it’s important to note that not all devices across their product line uniformly implement these advanced security features. In some instances, key material may end up being stored unencrypted in standard memory, depending on the specific device and its configuration. ​Silicon Labs+2Silicon Labs+2Silicon Labs+2

The Jury is still out…
To mitigate potential security risks, Silicon Labs introduced the Secure Vault™ technology, an integrated suite of security features designed to protect devices, data, and intellectual property from evolving threats. Secure Vault includes capabilities such as secure key management, anti-tamper protection, and secure boot with rollback prevention.

HTH

GL :slight_smile: PJ :v: