--- title: "Cybersecurity Frameworks: NIST, ISO 27001, NIS 2, ACN" description: "NIST CSF, ISO 27001, NIS 2 and the ACN baseline compared: scope, mandatory vs voluntary, certification, and a decision matrix for Italian organizations." canonical: https://www.aegister.com/en/cms/insights/cybersecurity-frameworks-nist-iso-27001-nis-2-acn-comparison/ url: /en/cms/insights/cybersecurity-frameworks-nist-iso-27001-nis-2-acn-comparison/ lang: en --- ![](/static/images/header-contact.webp) # Cybersecurity Frameworks Compared: NIST CSF, ISO 27001, NIS 2, ACN Baseline --- ![Cybersecurity Frameworks Compared: NIST CSF, ISO 27001, NIS 2, ACN Baseline](/static/images/cms/framework-cybersecurity-confronto-nist-iso-27001-nis-2-acn.webp) ## Cybersecurity Frameworks Compared: NIST CSF, ISO 27001, NIS 2, ACN Baseline April 29, 2026 [NIST CSF](/en/cms/keyword/nist-csf/) [ISO 27001](/en/cms/keyword/iso-27001/) [ISMS](/en/cms/keyword/isms/) [cybersecurity framework](/en/cms/keyword/cybersecurity-framework/) +6 ## Key Takeaways - NIST CSF 2.0 is a voluntary risk-management framework organized around Govern, Identify, Protect, Detect, Respond and Recover. - ISO/IEC 27001:2022 is a certifiable information security management system standard. - NIS 2 is not a framework choice: for in-scope entities it is a legal obligation implemented in Italy by Legislative Decree 138/2024. - The ACN baseline translates part of the Italian NIS implementation into operational security expectations for NIS subjects. - The best choice depends on the organization's objective: certification, legal compliance, executive risk language or operational baseline. - Most mature organizations combine them instead of choosing one in isolation. ## Scope of This Article This article compares NIST CSF, ISO/IEC 27001, NIS 2 and the ACN baseline for Italian organizations. It explains their purpose, legal nature, certification value and practical combination. ## Why Different Cybersecurity Frameworks Exist Cybersecurity frameworks differ because they solve different governance problems. Some create a common risk language. Some define certifiable management-system requirements. Some impose legal obligations. Others translate law into operational controls. The mistake is to ask which framework is best in the abstract. The right question is: what decision must the organization support? A board risk conversation, a customer certification request, a NIS 2 legal obligation and an ACN evidence review do not require exactly the same artifact. ## NIST Cybersecurity Framework 2.0 NIST describes the Cybersecurity Framework as a tool to help organizations understand and improve their management of cybersecurity risk ([NIST Cybersecurity Framework](https://www.nist.gov/cyberframework)). Version 2.0 is organized around six functions: Govern, Identify, Protect, Detect, Respond and Recover. NIST CSF is useful when an organization needs a strategic operating model, executive language, current-state and target-state profiles, and mapping across other references. It is voluntary and not a certification standard. Its value is clarity, prioritization and communication. ## ISO/IEC 27001:2022 ISO/IEC 27001 is a management-system standard for information security. ISO describes it as the best-known standard for information security management systems and says it defines requirements an ISMS must meet ([ISO/IEC 27001:2022](https://www.iso.org/standard/27001)). ISO/IEC 27001 is valuable when customers, partners or regulators expect a certifiable model. It structures risk assessment, controls, management review, internal audit, corrective action and continual improvement. It does not eliminate legal obligations, but it gives the organization a disciplined operating system for meeting them. ## NIS 2 and Legislative Decree 138/2024 NIS 2 is a European cybersecurity directive for sectors and entities that provide essential or important services. It includes risk-management, governance and incident-reporting obligations. Italy implemented NIS 2 through Legislative Decree 138/2024 ([Directive (EU) 2022/2555](https://eur-lex.europa.eu/eli/dir/2022/2555/oj), [Legislative Decree 138/2024](https://www.gazzettaufficiale.it/eli/id/2024/10/01/24G00155/SG)). For an in-scope subject, NIS 2 is not optional and cannot be replaced by another framework. ISO/IEC 27001 or NIST CSF may help organize work, but the legal perimeter, deadlines, notifications and supervisory powers come from the NIS legal framework. ## ACN Baseline and Categorization In Italy, ACN provides operational determinations, guidance and platform procedures for NIS subjects. The baseline measures and categorization model make the NIS program more concrete: organizations must translate broad obligations into governance, inventory, risk, incident, continuity and evidence activities. For the Italian context, see Aegister's guides on [ACN baseline measures](/en/cms/insights/nis2-basic-measures-acn/) and [NIS activity and service categorization](/en/cms/insights/nis-activity-service-categorization-acn-2026-model/). ## Quick Comparison Table | Dimension | NIST CSF 2.0 | ISO/IEC 27001:2022 | NIS 2 | ACN baseline | | --- | --- | --- | --- | --- | | Origin | NIST, United States | ISO and IEC | European Union | Italian ACN | | Nature | Voluntary framework | Certifiable standard | Legal obligation for in-scope entities | National operational requirement/guidance | | Primary purpose | Risk communication and program structure | Management-system governance | Cyber resilience and incident accountability | Concrete baseline implementation for NIS subjects | | Certification | No | Yes, through accredited certification bodies | No generic certification substitute | No generic certification substitute | | Approach | Risk-based profiles and functions | Risk-based ISMS with controls | Mandatory risk-management and reporting duties | Operational controls and evidence expectations | | Market signal | Maturity and common language | Auditable assurance to customers | Regulatory compliance requirement | Italian NIS readiness | ## Operational Mapping: How They Combine A pragmatic architecture is to use NIST CSF as the executive map, ISO/IEC 27001 as the certifiable management system, NIS 2 as the legal perimeter and ACN baseline measures as the Italian operational checklist. This avoids duplication. A risk assessment can feed ISO/IEC 27001, NIS 2 and board governance. A log-management control can support ACN evidence, NIS 2 incident readiness and NIST Detect. A supplier-risk procedure can support ISO controls, NIS 2 supply-chain measures and procurement assurance. ## Which Framework to Adopt First | Situation | Starting point | Why | | --- | --- | --- | | You are in NIS 2 scope in Italy | NIS legal scope + ACN baseline | Legal deadlines and supervisory expectations come first | | You need a customer-facing certification | ISO/IEC 27001 | It is certifiable and widely recognized | | You need an executive cybersecurity roadmap | NIST CSF 2.0 | It is clear for governance and target profiles | | You want to reduce duplicate compliance work | Combined control map | One evidence model can serve multiple regimes | ## Common Adoption Mistakes - **Confusing control catalogues and management systems:** controls do not replace governance. - **Choosing the popular label:** the best framework depends on legal scope and business objective. - **Duplicating evidence:** separate spreadsheets for each regime create inconsistent answers. - **Treating frameworks as checklists:** risk context and ownership matter more than formal completion. - **Ignoring Italian ACN specifics:** global frameworks must be mapped to national NIS requirements. ## How Aegister Uses This Mapping Aegister's ISO certification journey, NIS 2 content and ACN baseline work are designed to converge rather than create parallel compliance tracks. For related reading, see the [Aegister ISO certifications overview](/en/cms/insights/aegister-iso-certifications-2026-overview/), the [ISO 27001 news](/en/cms/insights/aegister-iso-27001-certification-2026/), the [UNI/PdR 174:2025 article](/en/cms/insights/uni-pdr-174-2025-nis-iso-27001/) and the [NIS 2 impact guide](/en/cms/insights/nis-2-directive-impact/). Organizations that need an operating model can combine [Virtual CISO support](https://aegister.com/en/solutions/virtual-ciso/) with evidence tracking through the [Cyber Console](https://aegister.com/en/solutions/cyber-console/). ## Example Mapping: Incident Management Incident management shows why framework mapping matters. The same operating process can satisfy several expectations if it is designed once and evidenced consistently. | Requirement family | What it asks | Reusable evidence | | --- | --- | --- | | NIST CSF Respond | Plan and execute response activities | Incident response plan, playbooks, lessons learned | | ISO/IEC 27001 | Manage information security incidents and improvements | Procedure, incident register, corrective actions | | NIS 2 | Handle and notify significant incidents under legal timelines | Notification procedure, escalation matrix, evidence log | | ACN baseline | Document operational incident-handling measures | Roles, exercises, logs, communication records | If these records are kept in separate systems, the organization duplicates work and increases inconsistency. If they are mapped centrally, one incident file can support management review, audit, customer assurance and regulatory readiness. ## Certification Is Not the Same as Compliance ISO/IEC 27001 certification can be a strong market signal, but it does not automatically prove compliance with every legal regime. It proves that the organization operates an ISMS within the certified scope and against the standard's requirements. Legal compliance depends on scope. A certified ISMS may exclude a business unit that is relevant for NIS 2. A NIS subject may need incident-notification workflows that go beyond the certification audit. Conversely, an organization outside NIS 2 may still use ISO/IEC 27001 to demonstrate maturity to customers. ## Board Reporting Across Frameworks The board does not need four parallel dashboards. It needs a unified view of risk exposure, control maturity, regulatory deadlines, unresolved findings and investment decisions. A concise board pack can map each objective to evidence: risk assessment, critical assets, incident readiness, supplier exposure, vulnerability backlog, audit findings and regulatory milestones. Framework names should support decisions, not bury them in terminology. ## Use Cases by Organizational Need | Need | Best primary reference | Companion reference | | --- | --- | --- | | Customer assurance | ISO/IEC 27001 | NIST CSF for executive narrative | | NIS legal readiness | NIS 2 and ACN baseline | ISO/IEC 27001 for management-system discipline | | Board-level cyber roadmap | NIST CSF 2.0 | ACN or ISO controls for evidence | | Supplier questionnaires | ISO/IEC 27001 and NIS mapping | Security evidence pack | | Product cybersecurity | Cyber Resilience Act | ISO/IEC 27001 and secure development controls | ## How to Avoid Duplicate Work Build one control library and map each control to several requirements. For example, the same access-review control can support ISO/IEC 27001, NIS 2 governance, customer questionnaires and NIST Identify/Protect outcomes. The same incident exercise can support NIS 2 notification readiness, ISO improvement and NIST Respond. The practical artifact is a crosswalk: requirement, control, owner, evidence, frequency and status. This is more useful than a long policy that nobody updates. ## When to Bring in External Support External support is useful when the organization lacks framework mapping experience, has conflicting customer requests, needs certification readiness, or must translate legal requirements into technical and organizational measures. The advisor should not simply deliver templates; it should leave the company with a reusable evidence model. ## A Maturity Path for Italian Organizations A practical maturity path starts with obligations, then builds reusable governance. The first step is legal scoping: NIS 2, DORA, GDPR, CRA, customer contracts and sectoral obligations. The second step is a baseline control map covering identity, assets, vulnerability management, logging, incident response, backup and supplier risk. The third step is evidence discipline. Every control should have an owner, frequency, proof and review mechanism. The fourth step is certification or external assurance, when the business needs market trust or customer validation. The fifth step is continuous improvement, where audit findings, incident lessons and supplier reviews update the control model. This order prevents the common mistake of pursuing certification before understanding mandatory obligations, or implementing legal measures without a management system able to keep them alive. ## Practical Minimum Artifact Set - framework crosswalk mapping NIST, ISO, NIS 2 and ACN requirements; - risk register connected to critical services and assets; - control library with owner, evidence and review frequency; - incident and vulnerability procedures with real registers; - supplier assurance model for cyber clauses and evidence requests; - board reporting template focused on decisions and residual risk. ## How to Communicate the Choice Internally The framework decision should be explained in business terms. Use NIS 2 and ACN when the driver is legal scope. Use ISO/IEC 27001 when the driver is customer trust and certification. Use NIST CSF when the driver is a common strategic language. This prevents teams from treating framework selection as an abstract standards debate. ## FAQ ### What is the best cybersecurity framework? There is no universal winner. NIST CSF is useful for governance, ISO/IEC 27001 for certification, NIS 2 for legal obligations and ACN baseline for Italian NIS implementation. ### Are NIST CSF and ISO 27001 compatible? Yes. NIST CSF can provide an executive risk map, while ISO/IEC 27001 provides a certifiable management-system structure. ### Does NIS 2 require ISO 27001? NIS 2 does not impose ISO/IEC 27001 certification as a universal requirement, but ISO can help structure evidence and governance. ### Can ACN baseline measures replace ISO 27001? No. ACN baseline measures support Italian NIS obligations. ISO/IEC 27001 is a separate certifiable management-system standard. ## Official Sources - [NIST Cybersecurity Framework](https://www.nist.gov/cyberframework) - [ISO/IEC 27001:2022](https://www.iso.org/standard/27001) - [Directive (EU) 2022/2555](https://eur-lex.europa.eu/eli/dir/2022/2555/oj) - [Legislative Decree 138/2024](https://www.gazzettaufficiale.it/eli/id/2024/10/01/24G00155/SG) - [ACN baseline determination](https://www.acn.gov.it/portale/documents/d/guest/detacn_obblighi_2511-v3_signed) Share this post ## Related News [![UNI/PdR 174:2025 for NIS Organizations Certified to ISO 27001: What It Changes Operationally](/static/images/cms/uni-pdr-174-2025-nis-iso-27001.webp)](/en/cms/insights/uni-pdr-174-2025-nis-iso-27001/) [UNI/PdR 174:2025 for NIS Organizations Certified to ISO 27001: What It Changes Operationally](/en/cms/insights/uni-pdr-174-2025-nis-iso-27001/) [ACN published UNI/PdR 174:2025 as an operational bridge between ISO/IEC 27001 and NIST CSF 2.0 for NIS-scoped organizations. 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