NIS 2 vs ISO 27001: How They Complement Each Other

Key Takeaways

Point	Summary
Nature	NIS 2 is an EU directive (mandatory); ISO 27001 is an international standard (voluntary)
Relationship	NIS 2 explicitly references international standards like ISO 27001 as a compliance foundation
Overlap	Approximately 70-80% of ISO 27001 controls map to NIS 2 requirements
Key differences	NIS 2 adds incident reporting timelines, management liability, and sector-specific obligations
Recommendation	Pursuing ISO 27001 is one of the most effective paths to NIS 2 compliance

Quick Answer: ISO 27001 and NIS 2 complement each other strongly. ISO 27001 certification addresses roughly 70-80% of NIS 2 requirements. The main NIS 2 additions are mandatory incident reporting timelines, explicit management liability, supply chain security requirements, and sector-specific obligations. Pursuing both provides comprehensive coverage.

Fundamental Differences

Aspect	NIS 2	ISO 27001
Type	EU Directive (law)	International Standard (voluntary)
Scope	Specific sectors and entity sizes	Any organization
Output	Legal compliance	Certificate (3-year cycle)
Enforcement	Fines up to 10M/2% turnover	No legal penalties (certification withdrawal)
Geographic focus	EU member states	Global
Management liability	Personal accountability	Governance requirement (no personal liability)
Incident reporting	24h/72h/1 month mandatory timelines	No mandatory external reporting timelines

Requirement Mapping

Areas Where ISO 27001 Covers NIS 2

NIS 2 Requirement (Article 21)	ISO 27001 Control
Risk analysis and policies	Clause 6.1.2 (Risk assessment), A.5.1 (Policies)
Incident handling	A.5.24-A.5.28 (Incident management)
Business continuity	A.5.29-A.5.30 (ICT readiness for business continuity)
Network and system security	A.8.20-A.8.34 (Technology controls)
Vulnerability management	A.8.8 (Management of technical vulnerabilities)
Cyber hygiene and training	A.6.3 (Information security awareness)
Cryptography	A.8.24 (Use of cryptography)
Access control	A.5.15-A.5.18, A.8.2-A.8.5 (Access controls)
Multi-factor authentication	A.8.5 (Secure authentication)
Asset management	A.5.9-A.5.14 (Asset management)

Areas Where NIS 2 Goes Beyond ISO 27001

NIS 2 Requirement	ISO 27001 Gap
24-hour early warning	ISO 27001 requires incident management but has no mandatory external reporting timeline
72-hour incident notification	No equivalent timeline requirement
1-month final report	No equivalent requirement
Personal management liability	ISO 27001 requires management commitment but no personal legal liability
Supply chain security specifics	ISO 27001 covers supplier relationships (A.5.19-A.5.23) but NIS 2 is more prescriptive
Sector-specific requirements	ISO 27001 is sector-agnostic; NIS 2 may have sector-specific implementing acts
Coordinated vulnerability disclosure	No equivalent in ISO 27001
National authority registration	ISO 27001 does not require registration with authorities

How ISO 27001 Supports NIS 2 Compliance

NIS 2 Encourages International Standards

Article 25 of NIS 2 explicitly states that entities may use relevant European and international standards and technical specifications when implementing cybersecurity risk-management measures. The European Commission may adopt implementing acts to specify which standards should be used, and ISO 27001 is widely expected to be referenced.

Practical Benefits

Benefit	Description
Established framework	ISO 27001 provides a proven structure for implementing cybersecurity measures
Documentation	The ISMS documentation largely satisfies NIS 2 policy requirements
Risk methodology	ISO 27001's risk assessment process meets NIS 2's risk analysis requirement
Continuous improvement	The Plan-Do-Check-Act cycle aligns with NIS 2's ongoing compliance expectations
Third-party validation	Certification provides independent evidence of security measures
Audit readiness	Regular ISO 27001 audits keep organizations prepared for NIS 2 supervision

What ISO 27001 Certified Organizations Need to Add

If you already have ISO 27001 certification, here is what you need to add for NIS 2 compliance:

1. Incident Reporting Procedures

• Establish the 24h/72h/1 month reporting process
• Identify your national CSIRT and competent authority
• Create report templates for each stage
• Define "significant incident" criteria aligned with NIS 2

2. Management Liability Framework

• Document management body's specific NIS 2 responsibilities
• Implement management cybersecurity training program
• Establish formal management approval process for security measures
• Create records demonstrating management oversight

3. Enhanced Supply Chain Requirements

• Review and strengthen supply chain security measures
• Ensure contracts include NIS 2-specific clauses
• Implement ongoing supplier monitoring processes
• Assess suppliers' development practices and cybersecurity measures

4. National Registration

• Register with relevant national authority as an essential or important entity
• Establish communication channels with CSIRT

Building a Combined Compliance Strategy

For Organizations Without ISO 27001

If you are starting from scratch, consider pursuing ISO 27001 certification as the foundation for NIS 2 compliance:

Step 1: Conduct a combined gap assessment covering both ISO 27001 and NIS 2

Step 2: Implement the ISMS according to ISO 27001, incorporating NIS 2-specific requirements from the start

Step 3: Add NIS 2-specific processes (incident reporting, management liability, supply chain enhancements)

Step 4: Achieve ISO 27001 certification

Step 5: Formalize NIS 2 compliance documentation and register with national authorities

This approach is more efficient than addressing each framework separately.

For Organizations with ISO 27001

Step 1: Conduct a gap analysis mapping your current ISMS against NIS 2 requirements

Step 2: Address the gaps (primarily incident reporting, management liability, supply chain)

Step 3: Update your ISMS documentation to reflect NIS 2-specific requirements

Step 4: Register with your national authority and CSIRT

Step 5: Incorporate NIS 2 requirements into your regular ISMS review cycle

Common Questions

Is ISO 27001 certification required for NIS 2 compliance?

No. ISO 27001 certification is not required for NIS 2 compliance. However, NIS 2 encourages the use of international standards, and ISO 27001 is one of the most effective ways to demonstrate compliance with many NIS 2 requirements. It provides a structured framework and independent validation that supervisory authorities are likely to view favorably.

If we have ISO 27001, are we automatically NIS 2 compliant?

No. While ISO 27001 covers a large portion of NIS 2 requirements, there are specific NIS 2 obligations that ISO 27001 does not address, particularly the mandatory incident reporting timelines, personal management liability, and sector-specific requirements. ISO 27001 is a strong foundation, not a complete solution.

Should we pursue ISO 27001 or focus on NIS 2 directly?

If you are starting from scratch and have the option, pursuing both is the most efficient approach. ISO 27001 provides a recognized certification that serves multiple purposes (customer trust, market access, regulatory compliance) while addressing the majority of NIS 2 requirements. The incremental effort for NIS 2-specific additions is relatively small when built on an ISO 27001 foundation.

How does the ISO 27001 audit cycle interact with NIS 2 supervision?

ISO 27001 operates on a 3-year certification cycle with annual surveillance audits. NIS 2 supervision is ongoing, with essential entities subject to proactive oversight at any time. The regular ISO 27001 audit cycle helps maintain compliance readiness for NIS 2 supervision, but organizations should be prepared for NIS 2 inspections outside the ISO audit schedule.