DISK46: A Secure, LUKS-Preinstalled Linux Distribution for Raspberry Pi Risk Assessment
I. Product Identification
DISK46 represents a specialized Linux distribution image, meticulously crafted with a preinstalled LUKS (Linux Unified Key Setup) encryption layer. This design choice prioritizes robust data security from the moment of deployment.
1. Target Hardware and Supported Distributions:
This system is specifically engineered for the Raspberry Pi platform, a popular series of small, single-board computers. To cater to a wide range of user preferences and project requirements, DISK46 offers compatibility with several prominent Linux distributions:
| Operating System | Version/Type | Key Features | Best Use Case |
|---|---|---|---|
| Ubuntu | 2024.04 Server | Optimized for headless/server use; no GUI | Server-side applications, IoT gateways |
| Ubuntu | 2024.04 Desktop | Full GUI; versatile for development and general computing | Interactive development, desktop use |
| Raspbian | 64-bit | General Raspberry Pi use, education, prototyping | Lightweight; optimized for Raspberry Pi |
2. Core System Features and Enhancements:
At its heart, DISK46 is built upon a clean, uncluttered operating system foundation. This minimalist approach ensures efficiency and reduces potential attack surfaces. On top of this, several key features and tools have been integrated to enhance security, manageability, and transparency:
| Componnent/Tool | Role | Beschreibung | Primary Use Case |
|---|---|---|---|
| Clevis | Automated decryption framework | Unlocks LUKS-encrypted volumes without manual input during boot | Remote or embedded systems needing unattended boot |
| Clevis-LUKS | LUKS integration module | Integrates LUKS encryption with Clevis automation | Secure unlocking of root and critical partitions |
| Clevis-initramfs | Boot integration package | Embeds Clevis into the initramfs to enable early boot decryption | Ensures encrypted volumes are unlocked before root mount |
| Syft | SBOM generation tool | Scans and lists installed software, libraries, and versions | Security auditing, compliance, and vulnerability tracking |
II. Risk context
The primary objective of this system is to ensure the encryption of the Raspberry Pi disk. This prevents unauthorized third parties from accessing the disk's contents simply by connecting it to another computer.
While disk encryption is a mandatory requirement under the Cyber Resilience Act (CRA), this system does not aim to fulfill all CRA requirements. A complete digital product certification would necessitate addressing other aspects of the product beyond just disk encryption.
Disk encryption is implemented using the standard LUKS utility, employing a robust password. This method is currently considered a strong encryption approach. The product incorporates the Tang / Clevis module for disk encryption, which means the associated risks with these encryption methods are an integral part of this product.
🔸 During the boot sequence, the product accesses the i46 server via Clevis to retrieve the disk password.
The product uses the Raspberry Pi LAN interface for communication by default. However, users can modify this communication method during system setup after the initial installation, which is also performed via a LAN interface.
III. Risks Associated with DISK46
Single Point of Failure during boot
The server responsible for disk encryption may experience malfunctions due to technical issues or cyberattacks like DDoS. Should this occur, IoT devices will be unable to boot and will continuously attempt to reconnect until the server becomes available.
Man In The Middle Attack
An attacker who gains control of the IoT device's network could redirect the device to a malicious server. This vulnerability arises because the device boots using an internet-located IP address. By redirecting the device, an attacker could then bypass the official server to access and decrypt the device's disk.
Linux Operating System
DISK46 offers no improvements to operating system reliability; therefore, all risks associated with a particular operating system version will also apply to DISK46.