Cyber Resilience Act (CRA) for firewalls, IDS and IPS: Guide to ETSI EN 304 636

17/09/2026

    In this article, we examine the draft of the vertical standard CRA EN 304 636, its scope, requirements and how to use this standard to achieve compliance.

    What is ETSI EN 304 636 within the Cyber Resilience Act framework?

    ETSI EN 304 636 is a vertical cybersecurity standard currently under development to support compliance with the Cyber Resilience Act (CRA) for firewalls, intrusion detection systems (IDS), and intrusion prevention systems (IPS). The standard defines cybersecurity requirements and assessment criteria specifically tailored to products whose primary purpose is to inspect, monitor, detect, prevent, or control network traffic for security purposes. It translates the broad essential cybersecurity requirements of the CRA into technical controls that can be implemented, assessed, and demonstrated by manufacturers.

    Like other CRA vertical standards, ETSI EN 304 636 follows the European standardization model:

    • Horizontal standards define general cybersecurity requirements applicable across product categories.
    • Vertical standards adapt those requirements to specific types of products and technologies.

     

    Once harmonized, compliance with ETSI EN 304 636 is expected to provide a presumption of conformity with the applicable CRA essential requirements for firewalls, IDS, and IPS products.

     

    EN 304 636 scope and applicability

    Which Products Does EN 304 636 Apply To?

     

    Firewalls

    Products that protect networks or systems by controlling and restricting data communications.

    • Network firewalls
    • Next-generation firewalls (NGFW)
    • Application firewalls
    • Web Application Firewalls (WAF)
    • Anti-spam gateways
    • Content filtering gateways

    Intrusion Detection Systems (IDS)

    Products that monitor traffic and identify malicious or suspicious activity.

    • Network-based IDS
    • Host-based IDS
    • Network forensics sensors
    • Threat-hunting platforms

    Intrusion Prevention Systems (IPS)

    Products that actively respond to detected threats by blocking or mitigating malicious activity.

    • Network-based IPS
    • Host-based IPS
    • Inline threat prevention platforms

    The standard applies regardless of whether the product is delivered as:

    • Physical appliance
    • Virtual machine
    • Software deployment
    • Containerized solution
    • Cloud-managed product

    Which products are not in scope?

    While ETSI EN 304 636 applies to products whose primary purpose is to inspect, monitor, detect, prevent, or control network traffic for cybersecurity purposes, several categories of products fall outside its scope.

    • Traditional routers and switches that provide network connectivity but do not implement firewall, IDS, or IPS security functions.
    • Unmanaged network switches with fixed functionality and no security inspection or security management capabilities.
    • Load balancers whose primary purpose is traffic distribution rather than security enforcement.
    • Network monitoring and performance management tools focused on availability, bandwidth analysis, or performance metrics without security inspection capabilities.

    In addition, ETSI EN 304 636 does not assess detection accuracy, threat detection rates, signature coverage, false-positive and false-negative performance, the quality of threat intelligence feeds, security policy effectiveness, or operational effectiveness in a particular customer environment.

    Therefore, a firewall, IDS, or IPS may fully comply with ETSI EN 304 636 while still requiring proper deployment, rule tuning, operational monitoring, and security management to achieve effective protection in practice.

     

    How is EN 304 636 structured?

    Main sections of the EN 304 636 standard

     

    Product Context

    This section defines:

    • Product functions
    • Assets
    • Capabilities
    • Deployment scenarios
    • User roles
    • Threat exposure
    • Operational environment

    Manufacturers must first define their product architecture before determining which requirements apply.

    Technical Requirements

    The standard establishes cybersecurity requirements covering:

    • Vulnerability management
    • Secure defaults
    • Updates
    • Access control
    • Data protection
    • Logging
    • Secure boot
    • Availability
    • Signature handling
    • Remote data processing solutions

    Compliance Assessment

    Clause 6 specifies how compliance is evaluated through:

    • Documentation review
    • Architecture analysis
    • Demonstration activities
    • Functional testing
    • Security verification activities

     

    Main cybersecurity requirements in EN 304 636

     

    Reference Description
    No Known Exploitable Vulnerabilities Manufacturers must maintain a machine-readable Software Bill of Materials (SBOM) and ensure that products do not contain known exploitable vulnerabilities when placed on the market. Third-party components and dependencies should be continuously assessed against vulnerability databases and security advisories.
    Secure by Default Configuration Products must be delivered in a secure state, with only necessary interfaces, services, and protocols enabled. Security controls should be activated by default, and diagnostic or maintenance interfaces should remain disabled unless explicitly enabled and adequately protected.
    Secure Updates Products must support authenticated and integrity-protected update mechanisms. Manufacturers should provide secure update delivery, audit logging of update activities, validation of update authenticity, and mechanisms to recover safely from failed update attempts.
    Authentication and Access Control The standard requires strong authentication and authorization mechanisms, including user authentication, unique credentials, password protection policies, session management, role-based authorization, privilege separation, and secure administration protocols.
    Data Protection Manufacturers are expected to protect credentials, cryptographic material, configuration data, logs, and management communications. Protection applies both to data at rest and data in transit, ensuring confidentiality, integrity, and controlled access.
    System Integrity Products must implement mechanisms to ensure the integrity of firmware, software, and operational components. Key expectations include secure boot, trusted boot chains, integrity verification, protection of recovery functions, and generation of integrity-related audit events.
    Availability and Fail-Secure Behaviour Products must remain secure during abnormal conditions and attack scenarios. Controls include rate limiting, connection throttling, Denial-of-Service (DoS) resilience, automatic recovery capabilities, and fail-secure handling of traffic when inspection cannot be completed.
    Monitoring and Logging Security-relevant activities must be recorded through comprehensive audit logs. Logged events should include authentication attempts, configuration changes, update operations, system events, security incidents, and unauthorized actions.
    Signature and Threat Intelligence Management Products using signature-based detection or threat intelligence feeds must protect signature databases against tampering, rollback attacks, corruption, and unauthorized modifications. Secure validation and update mechanisms must be implemented.
    Remote Data Processing Solutions (RDPS) Products using signature-based detection or threat intelligence feeds must protect signature databases against tampering, rollback attacks, corruption, and unauthorized modifications. Secure validation and update mechanisms must be implemented.

     

    Vulnerability handling conformity

    ETSI EN 304 636 places significant emphasis on the ability of firewall, IDS, and IPS products to identify, manage, and remediate vulnerabilities throughout their operational lifecycle. Conformity in this area is not limited to the existence of a vulnerability management process; manufacturers must demonstrate that vulnerabilities are systematically monitored, assessed, addressed, and communicated in a manner consistent with the product's cybersecurity objectives.

    Secure vulnerability management process

    Manufacturers should establish and maintain a documented vulnerability handling process covering the receipt, analysis, prioritization, remediation, and disclosure of security vulnerabilities. The process should include clearly defined responsibilities, decision-making criteria, and mechanisms for tracking vulnerabilities from identification through resolution. Evidence should demonstrate that vulnerability management activities are integrated into both product development and post-market maintenance practices.

    Vulnerability monitoring and assessment

    A compliant product lifecycle should include continuous monitoring of potential sources of security vulnerabilities, including internally developed components, third-party software, open-source dependencies, and supplied security services. Manufacturers should be able to assess the potential impact of identified vulnerabilities on product security functions and determine the appropriate remediation actions according to risk.

    Particular attention should be given to components identified within the product's Software Bill of Materials (SBOM), enabling the manufacturer to rapidly determine whether newly disclosed vulnerabilities affect the evaluated product.

    Security updates and remediation

    Conformity requires the capability to deliver corrective security updates when vulnerabilities are identified. Update mechanisms should ensure the authenticity and integrity of distributed software, firmware, configuration packages, and other security-relevant components. Manufacturers should demonstrate that security patches can be deployed in a controlled manner while minimizing the risk of unauthorized modification, downgrade attacks, or installation failures.

    Where vulnerabilities cannot be immediately remediated, manufacturers should be able to provide documented mitigation measures, compensating controls, or operational guidance to reduce associated risks until a permanent fix becomes available.

    Vulnerability disclosure and communication

    Manufacturers should maintain procedures for receiving reports from external researchers, customers, and other stakeholders. Publicly available reporting channels, coordinated vulnerability disclosure practices, and transparent security communications contribute to the effectiveness of the overall vulnerability handling framework.

    Assessment evidence may include published vulnerability handling policies, security advisories, remediation records, and examples demonstrating how previously identified vulnerabilities were managed and communicated to affected users.

    Assessment considerations

    During conformity assessment, evaluators are likely to review documented vulnerability management procedures, vulnerability analysis records, remediation workflows, security update mechanisms, and associated technical evidence. Manufacturers should be prepared to demonstrate traceability between identified vulnerabilities, risk assessments, corrective actions, and released updates.

    The evaluation may also consider how the organization maintains awareness of vulnerabilities affecting third-party components, verifies the effectiveness of remediation measures, and ensures that security-relevant updates can be safely distributed throughout the supported lifetime of the product.

    What does conformity demonstrate?

    Conformity with vulnerability handling requirements demonstrates that the manufacturer has implemented a structured and repeatable approach to managing security weaknesses throughout the product lifecycle. It provides confidence that vulnerabilities can be identified, assessed, communicated, and remediated through controlled processes supported by appropriate technical and organizational measures. However, conformity does not guarantee the absence of vulnerabilities. Rather, it demonstrates the manufacturer's capability to respond effectively when vulnerabilities are discovered and to maintain the security posture of the product over time.

    How to use ETSI EN 304 636

    ETSI EN 304 636 follows a risk-based approach, meaning requirements depend on the product's functionality, deployment model, and external dependencies. To achieve compliance, manufacturers should:

    • Define the Product Context: Identify the product's security functions, deployment scenarios, user roles, interfaces, and external dependencies.
    • Determine Applicable Requirements: Assess which requirements apply based on risk factors, threat scenarios, optional features, signature management capabilities, and remote service dependencies.
    • Collect Compliance Evidence: Prepare supporting documentation and evidence, including SBOMs, update mechanisms, secure boot implementation, authentication controls, logging capabilities, cryptographic inventories, and vulnerability management records.
    • Prepare for Assessment: Ensure the product is ready for documentation review, demonstrations, configuration inspection, functional testing, and security validation activities.

     

    Impact on stakeholders

    Product teams

    Responsible for implementing the technical controls required by the standard, including secure-by-design practices, secure updates, SBOM management, secure boot, attack surface reduction, and technical documentation.

    Security teams

    Lead threat modelling, vulnerability management, cryptographic reviews, security testing, monitoring capabilities, and preparation of assessment evidence.

    Legal and compliance teams

    Ensure alignment with CRA requirements, maintain traceability between regulatory obligations and technical controls, review compliance documentation, and support conformity assessment activities.

    Customers and users

    Benefit from products that provide secure default configurations, strong access controls, secure updates, data protection, integrity protection, auditability, and improved long-term cybersecurity maintenance. Compliance increases confidence in product security but does not replace proper deployment and operational security practices.

     

    How Applus+ Laboratories can support CRA compliance

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