NIS2 vs. ISO 27001: How to Leverage Your ISMS for Compliance

For many CISOs, Heads of IT, and Compliance Officers, the NIS2 Directive introduces new, stringent cybersecurity obligations across Europe. The good news is that for organisations already certified to ISO 27001, you are not starting from scratch. ISO 27001, the international standard for information security management, provides a robust framework that significantly overlaps with the requirements of NIS2. Leveraging your existing Information Security Management System (ISMS) is not just efficient; it’s a strategic imperative for streamlining your NIS2 compliance journey.

This guide will show you how to map your ISO 27001 controls to NIS2 requirements, highlight the critical differences, and outline how your current certification can accelerate your path to NIS2 compliance, saving valuable time and resources.

Mandatory Regulation vs. Voluntary Standard: The Key Difference

Before diving into the technical overlaps, it’s crucial to understand the fundamental difference between NIS2 and ISO 27001:

  • NIS2 Directive (EU 2022/2555): A Mandatory Legal Obligation
    • NIS2 is a legislative act of the European Union. Once transposed into national law by Member States, it becomes a mandatory legal requirement for all in-scope entities.
    • It sets a baseline for cybersecurity risk management and incident reporting, with specific requirements and strict deadlines.
    • Non-compliance carries significant administrative fines (up to €10 million or 2% of global turnover for Essential Entities; €7 million or 1.4% for Important Entities) and potential personal liability for management bodies.
    • It focuses on specific sectors deemed critical for the functioning of society and the economy, aiming to enhance the overall cyber resilience of the EU.
  • ISO/IEC 27001: A Voluntary International Standard
    • ISO 27001 is an international standard that provides a framework for establishing, implementing, maintaining, and continually improving an Information Security Management System (ISMS).
    • Certification to ISO 27001 is voluntary. Organisations choose to adopt it to demonstrate their commitment to information security, manage risks systematically, and often to meet contractual or stakeholder requirements.
    • It is technology-neutral and provides a generic set of controls (Annex A) that can be adapted to any organisation.
    • While it helps demonstrate good security practices, ISO 27001 certification alone does not automatically equate to NIS2 compliance.

In essence, NIS2 tells you *what* you must achieve and *when* you must report, backed by legal force. ISO 27001 provides a proven, internationally recognised framework for *how* to manage and implement those security objectives effectively. The synergy lies in leveraging the ‘how’ of ISO 27001 to meet the ‘what’ of NIS2.

Mapping Table: ISO 27001 Annex A Controls to NIS2 Article 21 Requirements

NIS2 Article 21 outlines the core cybersecurity risk management measures that Essential and Important Entities must implement. These measures are designed to be comprehensive and proportionate to the risks faced. Fortunately, a significant portion of these requirements aligns well with the controls specified in Annex A of ISO 27001:2022.

Below is a simplified mapping to illustrate how key ISO 27001:2022 Annex A controls can address NIS2 Article 21 requirements. This is not an exhaustive list but demonstrates the strong foundational overlap.

NIS2 Article 21 (2) Requirements for Cybersecurity Risk Management Measures:

  1. Policies on risk analysis and information system security;
  2. Incident handling;
  3. Business continuity, such as backup management and disaster recovery, and crisis management;
  4. Supply chain security, including security-related aspects concerning the relationship between each entity and its direct suppliers or service providers;
  5. Security in network and information systems acquisition, development, and maintenance, including vulnerability handling and disclosure;
  6. Policies and procedures regarding the use of cryptography and, where appropriate, encryption;
  7. Human resources security, access control, and asset management;
  8. The use of multi-factor authentication or continuous authentication solutions, secured voice, video and text communications, and secured emergency communication systems within the entity, where appropriate.

Mapping of ISO 27001:2022 Annex A Controls to NIS2 Article 21 Requirements:

NIS2 Article 21 (2) RequirementRelevant ISO 27001:2022 Annex A Control(s)Explanation of Overlap
(a) Policies on risk analysis and information system securityA.5.1 Information security policies
A.5.7 Threat intelligence
A.5.3 Information security roles and responsibilities		ISO 27001 mandates an overarching information security policy derived from risk assessments (A.5.1) and assigns clear responsibilities (A.5.3), directly supporting NIS2’s policy requirement. Threat intelligence (A.5.7) is key for effective risk analysis.
(b) Incident handlingA.5.24 Information security incident management
A.5.27 Collection of evidence
A.8.16 Monitoring activities		ISO 27001’s comprehensive incident management (A.5.24) covers detection, analysis, response, and recovery, aligning with NIS2. Monitoring (A.8.16) supports early detection. NIS2, however, adds specific reporting timelines.
(c) Business continuity, backup management, disaster recovery, and crisis managementA.5.30 ICT readiness for business continuity
A.5.31 Business continuity planning
A.5.32 Disaster recovery		ISO 27001 requires robust plans for ICT readiness, business continuity (A.5.30, A.5.31), and disaster recovery (A.5.32), which are core components of NIS2’s resilience mandate. NIS2 may require more detailed testing or specific crisis communication plans.
(d) Supply chain securityA.5.19 Information security in supplier relationships
A.5.23 Information security for use of cloud services
A.6.3 Information security in supplier relationships		ISO 27001 addresses supplier security management (A.5.19, A.6.3) and cloud service security (A.5.23), directly supporting NIS2’s focus on supply chain risks. NIS2 often requires more explicit due diligence and contractual provisions.
(e) Security in network and information systems acquisition, development, and maintenance, including vulnerability handling and disclosureA.8.15 Development security
A.8.25 Secure development life cycle
A.8.26 Application security requirements
A.8.28 Secure coding
A.8.29 Security testing in development and acceptance
A.8.8 Management of technical vulnerabilities		ISO 27001 provides extensive controls for security throughout the SDLC (A.8.25, A.8.26, A.8.28, A.8.29) and vulnerability management (A.8.8), forming a strong basis for this NIS2 requirement.
(f) Policies and procedures regarding the use of cryptography and, where appropriate, encryptionA.5.25 Information security for the use of cryptographyISO 27001 explicitly requires a policy for the effective use of cryptography (A.5.25), directly fulfilling NIS2’s mandate.
(g) Human resources security, access control, and asset managementA.6.4 Disciplinary process
A.6.6 Terms and conditions of employment
A.6.7 Information security awareness, education and training
A.7.2 User access provisioning
A.7.3 Privileged access rights
A.7.4 Information access restriction
A.7.8 User access review
A.5.9 Inventory of information and other associated assets
A.5.10 Acceptable use of information and other associated assets		ISO 27001 has dedicated sections for HR security (A.6.x), comprehensive access control (A.7.x), and asset management (A.5.9, A.5.10), aligning directly with NIS2.
(h) The use of multi-factor authentication (MFA) or continuous authentication solutions, secured voice, video and text communications, and secured emergency communication systemsA.8.5 Secure authentication
A.8.2 Secure coding (for communications)
A.8.1 Secure development life cycle (for systems)		While ISO 27001 mandates secure authentication (A.8.5), NIS2 is more prescriptive, explicitly calling out MFA/continuous authentication and the security of communication systems. An ISO 27001 compliant ISMS would likely already have these, but NIS2 makes them mandatory.

Critical Note on Differences:

While the overlap is substantial, key differences mean ISO 27001 certification alone is insufficient for full NIS2 compliance. NIS2 introduces:

  • Specific Incident Reporting Timelines: Article 23 mandates strict reporting timelines (e.g., initial notification within 24 hours, update within 72 hours, final report within one month) to competent authorities, which ISO 27001 does not specify.
  • Enhanced Management Accountability: NIS2 places clear responsibility on management bodies for approving and overseeing cybersecurity risk management measures, with potential personal liability.
  • Supply Chain Due Diligence: NIS2 demands specific due diligence regarding the cybersecurity practices of direct suppliers and service providers, potentially requiring more rigorous assessments than typically performed under ISO 27001.
  • Supervisory Powers: National authorities under NIS2 have significant powers to conduct audits, request information, and impose fines, a regulatory layer absent from voluntary ISO 27001 certification.
  • Specific Technology Mandates: The explicit mention of MFA (Article 21(2)(h)) and secure communication systems is more direct than a general ISO 27001 control.

Vulnerability Management & Scanning: A Core Pillar of NIS2 Compliance (Article 21(2)(e))

NIS2 explicitly mandates robust security in network and information systems acquisition, development, and maintenance, crucially including vulnerability handling and disclosure (Article 21(2)(e)). For CISOs, this isn’t merely a suggestion; it’s a fundamental requirement for maintaining cyber resilience. Vulnerability management, with regular scanning as its cornerstone, directly addresses this mandate.

The Role of Vulnerability Scanning:

Vulnerability scanning is the automated process of identifying security weaknesses (vulnerabilities) in your IT systems, applications, and networks. It acts as an early warning system, helping organisations uncover exploitable flaws before malicious actors do. Under NIS2, effective scanning is vital for:

  • Proactive Risk Identification: Continuously discovering and assessing new vulnerabilities that could lead to security incidents.
  • Compliance Assurance: Providing demonstrable evidence that your organisation is actively seeking out and addressing weaknesses as required by the Directive.
  • Reducing Attack Surface: Enabling timely patching and configuration changes to close security gaps.

Scope, Frequency, and Integration:

A comprehensive NIS2-aligned vulnerability management program must encompass various aspects:

  • Continuous & Regular Scanning: Implement automated internal and external vulnerability scans on a defined, regular basis (e.g., weekly, monthly), complemented by ad-hoc scans after significant infrastructure changes.
  • Comprehensive Scope: Scan a wide range of assets, including network devices, servers, workstations, cloud environments, web applications, and containers. This also extends to identifying misconfigurations.
  • Integrated Process: Scanning is just one step. An effective program requires a documented process for:
    • Identification: Detecting vulnerabilities through scanning.
    • Assessment: Prioritising vulnerabilities based on severity, exploitability, and potential impact on critical services (linking back to your risk analysis policies).
    • Remediation: Implementing patches, configuration changes, or other mitigating controls.
    • Verification: Re-scanning to confirm that vulnerabilities have been successfully addressed.
    • Reporting & Disclosure: Documenting the process and, where applicable, adhering to NIS2’s incident reporting requirements if a vulnerability leads to an actual security incident.

Leveraging ISO 27001 for Vulnerability Management:

Organisations with an ISO 27001-certified ISMS are well-equipped here. ISO 27001:2022’s Annex A control A.8.8 (Management of technical vulnerabilities) directly guides the establishment of a robust vulnerability management process. This includes:

  • Establishing procedures to identify and remediate vulnerabilities.
  • Using vulnerability scanning tools.
  • Staying informed about new threats and vulnerabilities.
  • Defining roles and responsibilities for managing vulnerabilities.

By effectively implementing A.8.8, you will have a strong foundation to meet the NIS2 requirements for vulnerability handling, demonstrating a proactive approach to maintaining the security of your network and information systems.

How ISO 27001 Certification Accelerates Your NIS2 Journey

If your organisation already holds ISO 27001 certification (especially to the 2022 version), you are in a significantly advantageous position for achieving NIS2 compliance. Your ISMS provides a robust foundation upon which to build the additional NIS2-specific requirements.

Here’s how your ISO 27001 certification accelerates your NIS2 journey:

  • Established Risk Management Framework: ISO 27001 mandates a systematic, risk-based approach to information security. This aligns perfectly with NIS2’s requirement for implementing cybersecurity risk management measures (Article 21). You already have the processes for identifying, assessing, and treating risks.
  • Defined Security Policies and Procedures: Your ISMS includes documented policies, procedures, and controls covering various aspects of information security, from access control to incident management. These can be directly adapted and enhanced to meet NIS2’s specific mandates.
  • Culture of Security Awareness: ISO 27001 promotes a security-conscious culture through training and awareness. This internal readiness makes it easier to implement new NIS2 requirements and gain employee buy-in.
  • Incident Management Capabilities: An ISO 27001-compliant organisation already has incident response plans and capabilities in place. You will primarily need to adjust these to incorporate NIS2’s specific reporting timelines and communication channels with national authorities.
  • Supply Chain Security Foundations: While NIS2 adds more rigor, ISO 27001 includes controls for managing supplier relationships. This provides a starting point for the enhanced due diligence and contractual requirements under NIS2.
  • Demonstrable Evidence: An ISMS generates extensive documentation (e.g., risk assessment reports, policies, audit logs) that serves as crucial evidence of your security posture. This documentation can be readily adapted to demonstrate compliance with NIS2 requirements during potential audits by national authorities.
  • Continuous Improvement Cycle: ISO 27001’s Plan-Do-Check-Act (PDCA) cycle ensures ongoing review and improvement of your security posture. This continuous process is ideal for adapting to evolving NIS2 guidance and maintaining compliance over time.

The key strategy is to perform a comprehensive **gap analysis**. This involves reviewing your existing ISO 27001 ISMS against the full text of the NIS2 Directive (and its national transposition laws) to identify where additional measures, modifications, or specific documentation are required. Focus on the NIS2-specific reporting obligations, the enhanced supply chain due diligence, and any new technological mandates (like explicit MFA requirements).

How Nistra Bridges the Gap Between ISO 27001 and NIS2

Even with an ISO 27001-certified ISMS, bridging the specific gaps to achieve NIS2 compliance can be a complex and time-consuming process. Manually mapping hundreds of controls, understanding the nuances of reporting obligations, and staying abreast of national transposition laws requires dedicated expertise and resources.

Nistra’s AI-powered platform is designed to streamline this integration, making your NIS2 compliance journey efficient and effective. Our **NIS2 Compliance Assessment** is specifically built to assist organisations leveraging existing ISO 27001 frameworks.

Nistra helps you by:

  • Automated Gap Analysis: Our platform intelligently cross-references your existing ISO 27001 controls and documentation against the detailed requirements of NIS2 (Article 21 and others), highlighting precise gaps and areas needing attention.
  • Actionable Remediation Plans: For identified gaps, Nistra provides specific, prioritised recommendations based on ENISA guidance and national interpretations, translating high-level requirements into clear, executable tasks.
  • Evidence Mapping: Easily map your existing ISO 27001 evidence (policies, procedures, audit logs) to fulfil corresponding NIS2 requirements, reducing duplication of effort and streamlining your audit readiness.
  • Incident Reporting Workflows: Nistra helps you adapt your existing incident management processes to meet NIS2’s strict reporting timelines and formats, ensuring seamless communication with competent authorities.
  • Continuous Compliance Monitoring: Beyond initial certification, Nistra continually monitors changes in NIS2 guidance and national laws, helping you maintain ongoing compliance without manual tracking.
  • Supply Chain Due Diligence Support: Facilitate the enhanced supply chain assessments required by NIS2, ensuring your third-party risks are adequately managed and documented.

Leverage your ISO 27001 investment to its full potential. Nistra simplifies the transition to NIS2, ensuring comprehensive and demonstrable compliance.

Get started with your Nistra NIS2 Compliance Eligibility Assessment today.

Citations:

Directive (EU) 2022/2555 of the European Parliament and of the Council of 14 December 2022 on measures for a high common level of cybersecurity across the Union, amending Regulation (EU) No 910/2014 and Directive (EU) 2018/1972, and repealing Directive (EU) 2016/1148 (NIS 2 Directive). Official Journal of the European Union. L 333/80. (Accessible via EUR-Lex: https://eur-lex.europa.eu/eli/dir/2022/2555/oj)

ISO/IEC 27001:2022, Information security, cybersecurity and privacy protection — Information security management systems — Requirements. (Refer to official ISO standard documentation.)

ISO/IEC 27002:2022, Information security, cybersecurity and privacy protection — Information security controls. (Refer to official ISO standard documentation.)

European Union Agency for Cybersecurity (ENISA). “Recommendations for the security of supply chains.” (Refer to relevant ENISA publications and guidance on their official website: www.enisa.europa.eu)

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