Clea OS Security Overview

Overview

Clea OS is an embedded Linux operating system framework designed for industrial and connected devices. It provides security capabilities and development practices intended to support the creation and maintenance of secure embedded products.

The effective security posture of a Clea OS based product depends on several factors, including:

• the selected hardware platform;
• the Clea OS build and configuration;
• the enabled services and interfaces;
• the device provisioning process;
• the applications installed by the system integrator;
• the network and physical deployment environment;
• the product maintenance and update strategy.

Security capabilities can vary between hardware platforms and Clea OS configurations. Some capabilities, including Secure Boot, image signing and storage encryption, require specific hardware support, build configuration and provisioning. Unless otherwise stated in the relevant platform documentation, these capabilities must be explicitly enabled and are not enabled by default.

This page provides a high-level overview of the Clea OS security model, its main security capabilities and the measures expected from the deployment environment.

Security Model and Shared Responsibility

Clea OS security follows a shared-responsibility model involving the operating system, the underlying hardware platform and the system integrator or operator.

Clea OS

Clea OS provides the operating system components, build framework and supported security mechanisms used to create the software image. Depending on the selected configuration and platform, these mechanisms can include:

• Secure Boot integration;
• signed software artifacts and update bundles;
• A/B system updates and recovery mechanisms;
• host-based firewall configuration;
• secure communication protocols;
• device identity and authentication mechanisms;
• support for protected storage;
• security logging;
• Software Bill of Materials generation;
• vulnerability identification and management.

Hardware platform

The underlying hardware platform can provide security capabilities such as:

• hardware root of trust;
• boot artifact authentication;
• Trusted Platform Module or Secure Element;
• hardware-assisted key protection;
• cryptographic acceleration;
• memory and execution protection mechanisms.

Availability and implementation depend on the selected processor, board and Clea OS release.

System integrator and operator

The system integrator or operator is responsible for configuring Clea OS for the final use case and maintaining the security of the deployed product. This includes:

• selecting and enabling the required security capabilities;
• provisioning production keys, certificates and device identities;
• securing administrative access;
• enabling only the required software components and services;
• integrating product applications securely;
• protecting the device physically and through network controls;
• monitoring the deployed system;
• maintaining software and security updates throughout the product lifecycle.

Changing the Clea OS configuration, adding applications or enabling additional services may modify the attack surface and should be evaluated as part of the security assessment of the final product.

Secure-by-Design Principles

Clea OS development and reference configurations apply secure-by-design principles intended to reduce vulnerabilities and limit the impact of potential security incidents.

These principles include:

• Secure defaults: access and functionality should be restricted unless explicitly required.
• Least privilege: users, applications and services should operate with only the permissions required to perform their functions.
• Minimal functionality: unnecessary packages, services, protocols and interfaces should not be enabled.
• Defense in depth: security should not depend on a single protection mechanism.
• Attack-surface reduction: exposed interfaces and externally reachable services should be limited to those required by the intended application.
• Input validation: externally supplied data should be validated before use.
• Open design: security should rely on established cryptographic algorithms and reviewed implementations rather than on secrecy of the design.
• Traceability: changes to software components and configurations should be identifiable and associated with a defined product release.
• Secure maintenance: vulnerabilities and security updates should be managed throughout the supported product lifecycle.

Security Capabilities

Secure Boot

On supported platforms, Clea OS can use hardware-assisted Secure Boot to authenticate boot artifacts before execution. The implementation and provisioning process are platform-specific.

Secure Boot requires correct key generation, image signing and hardware provisioning. On platforms that use irreversible security lifecycle states or one-time programmable fuses, the complete signed boot flow must be validated before production provisioning.

Secure Boot protects the authenticated boot chain. It does not, by itself, guarantee the integrity or confidentiality of every user-space file, application or data partition.

For implementation and provisioning instructions, see:

• Secure Boot on NXP platforms
• Secure Boot on Qualcomm platforms

Refer to the documentation associated with the selected platform and Clea OS release for additional platform-specific information.

Software and Data Protection

Clea OS can support optional mechanisms for protecting software artifacts, filesystems and stored data, depending on the platform and product configuration.

These mechanisms may include:

• signed boot and update artifacts;
• encrypted partitions or storage;
• hardware-backed key storage;
• TPM or Secure Element integration;
• protection of device certificates and credentials.

These mechanisms are not necessarily enabled in the default development configuration. The system integrator is responsible for selecting, enabling, provisioning and validating the mechanisms required by the final product.

Production cryptographic keys must not be stored in source-code repositories, public release packages, shared build directories or unprotected target storage. Where appropriate, keys should be managed using a controlled signing environment, secure key-management service or Hardware Security Module.

Secure Software Updates

Clea OS supports software update mechanisms intended to maintain system integrity and availability during field updates.

Depending on the product configuration, these mechanisms can include:

• A/B system partitioning;
• update integrity and authenticity verification;
• local update bundles;
• remote OTA update delivery;
• fallback or recovery following an unsuccessful update.

The frameworks used for such funtionalities are RAUC, the current default framework enabled, or SWUpdate that can be enabled alternatevly. Signing, encryption and rollback-protection capabilities depend on the selected platform and configuration and may require explicit enablement and provisioning.

The system integrator should:

• use only trusted update sources;
• protect update signing keys;
• verify the update and recovery procedure before deployment;
• ensure that interrupted or unsuccessful updates do not leave the device in an unrecoverable state;
• define how security updates are distributed throughout the supported product lifecycle.

Network and Communication Security

Clea OS provides mechanisms that can be used to reduce network exposure and protect communications.

Reference configurations can include:

• a host-based firewall;
• encrypted communication using protocols such as HTTPS and MQTT over TLS;
• certificate-based device authentication;
• secure remote administration;
• configurable network services.

The actual network exposure depends on the selected image, platform, installed applications and enabled services.

System integrators should enable only the services required by the intended application and restrict access through host-based and external network controls. Management interfaces should not be exposed directly to untrusted networks unless specifically required and protected by appropriate authentication, encryption and access restrictions.

Identity, Credentials and Access Control

Device and user identities must be protected throughout provisioning, operation and maintenance.

The final product configuration should:

• avoid shared or default production credentials;
• use unique device identities and certificates where supported;
• restrict administrative access to authorized personnel;
• use strong authentication mechanisms;
• protect private keys, passwords and tokens from unauthorized access;
• remove development accounts and credentials before production deployment;
• periodically review accounts and access permissions;
• revoke or replace compromised credentials.

Where SSH is enabled, the system integrator should restrict network access to trusted management hosts and use an authentication configuration appropriate for the intended operational environment.

Logging and Monitoring

Clea OS uses standard Linux logging facilities to record system and service events. The logs available on a device depend on the selected configuration and installed applications.

For production deployments, the system integrator should:

• identify the events relevant to security monitoring;
• protect logs from unauthorized access or modification;
• configure appropriate storage and retention limits;
• ensure that logging cannot exhaust available storage;
• use reliable time synchronization;
• forward relevant logs to a remote monitoring system when required by the operational environment;
• review security-relevant events and authentication failures.

Applications integrated into Clea OS should generate sufficient information to support troubleshooting, security monitoring and incident investigation without exposing passwords, private keys, tokens or other sensitive information.

Software Components and Vulnerability Management

Clea OS is built using the Yocto Project and includes software components originating from multiple upstream projects and suppliers.

Release-specific Software Bills of Materials are generated to provide traceability of included components. Clea OS uses standard formats such as SPDX and CycloneDX. Vulnerability Exploitability eXchange artifacts may also be provided to communicate available vulnerability applicability information.

Release-candidate and released software baselines can be correlated with public vulnerability information to identify known vulnerabilities in included components. Identified issues are assessed and managed according to the applicable vulnerability-management process.

Release artifacts, including the available SBOM and VEX files, are published on the Clea OS GitLab release page.

An SBOM or automated vulnerability match does not, by itself, indicate that a vulnerability is exploitable in a specific Clea OS configuration. Applicability can depend on factors such as:

• whether the affected code is included in the image;
• build-time options;
• enabled functionality;
• runtime configuration;
• network exposure;
• available mitigations;
• the hardware platform and deployment environment.

System integrators should consider both component vulnerability information and the security context of the final product.

Security Verification

Security verification activities are selected according to the product, release and applicable security scope. They can include:

• source-code review;
• Static Application Security Testing;
• Software Composition Analysis;
• verification of security requirements;
• threat-based and negative testing;
• validation of implemented threat mitigations;
• network exposure and listening-port analysis;
• known-vulnerability scanning;
• update integrity and rollback testing;
• resource exhaustion and service recovery testing.

Test coverage and results are associated with identified product versions and representative hardware configurations.

Security verification of Clea OS does not replace the security validation required for the final product. Applications, custom configurations, additional packages and deployment-specific integrations introduced by the system integrator must be evaluated within the final product security context.

Defense-in-Depth Measures for the Deployment Environment

Clea OS is intended to operate as part of a defense-in-depth environment. Security mechanisms implemented in the operating system should be complemented by physical, network, administrative and operational controls.

The system integrator or operator should apply the following measures as appropriate to the intended deployment.

Physical protection

• Install production devices in locations accessible only to authorized personnel.
• Prevent unauthorized access to debug, recovery, removable-media and hardware interfaces.
• Disable or physically restrict unused maintenance interfaces where possible.
• Define controlled procedures for device provisioning, maintenance and replacement.

Network protection

• Deploy devices within appropriately segmented networks.
• Use external firewalls or equivalent network controls to restrict inbound and outbound communication.
• Permit communication only with the systems and services required by the intended application.
• Do not expose management interfaces directly to the Internet unless specifically required and appropriately protected.
• Separate device-management traffic from untrusted or general-purpose network traffic where practical.
• Apply additional monitoring or intrusion-detection controls when required by the operational risk assessment.

Secure integration

• Use secure protocols when integrating Clea OS with external applications and services.
• Validate remote certificates and maintain the required trust anchors.
• Protect API credentials, device certificates and authentication tokens.
• Evaluate the security implications of enabling additional protocols, ports or services.
• Review the privileges granted to applications and containers added to the system.

Operational protection

• Maintain an inventory of deployed devices, software versions and relevant configurations.
• Apply security updates using trusted delivery mechanisms.
• Monitor security-relevant logs and system events.
• Protect backups of configuration, credentials and operational data.
• Define recovery procedures for failed updates, damaged storage and lost credentials.
• Periodically review accounts, certificates, exposed services and firewall rules.

These measures should be adapted to the security requirements, risk assessment and operational constraints of the final product.

Security Hardening Recommendations

Before deploying a Clea OS based product in production, the system integrator should review and harden the final configuration.

At minimum:

1. Remove development-only users, credentials, keys and certificates.
2. Replace shared credentials with product-specific or device-specific credentials.
3. Disable packages, services, interfaces and protocols that are not required.
4. Restrict administrative access to trusted users and management networks.
5. Review host-based firewall rules and apply a default-deny approach where appropriate.
6. Protect private keys, device certificates and authentication tokens.
7. Enable and provision supported Secure Boot and storage-protection capabilities when required by the product security assessment.
8. Configure secure update and recovery mechanisms.
9. Configure logging, retention and monitoring appropriate to the intended environment.
10. Verify the resulting network exposure and active services before production release.
11. Reassess the configuration when adding applications, changing platform components or enabling new interfaces.
12. Document deviations from the approved production security configuration.

Hardening activities should be validated on the final hardware, software image and production configuration.

Coordinated Vulnerability Disclosure

SECO operates a Coordinated Vulnerability Disclosure (CVD) process for potential security vulnerabilities affecting Clea OS and other SECO hardware, firmware and software products.

Potential security vulnerabilities can be reported in accordance with this process through the SECO Product Security Vulnerability Reporting page.

When reporting a potential vulnerability, include the affected product and version, required configuration, reproduction steps, potential impact and any relevant logs or proof-of-concept material.

Security testing must be performed only on products and systems that the researcher owns or is authorized to test.