ISO 27001
International standard for information security management systems
NIST 800-171
U.S. standard for protecting CUI in nonfederal systems.
Quick Verdict
ISO 27001 provides voluntary global ISMS certification for all industries, while NIST 800-171 mandates CUI protection for US federal contractors via contractual audits. Companies adopt ISO for broad compliance and market trust; NIST for DoD eligibility.
ISO 27001
ISO/IEC 27001:2022
Key Features
- Risk-based Information Security Management System
- 93 Annex A controls in four themes
- PDCA continual improvement cycle
- Internationally recognized certification standard
- Technology-agnostic across all industries
NIST 800-171
NIST SP 800-171 Revision 3
Key Features
- Protects CUI confidentiality in nonfederal systems
- 97 requirements across 17 control families
- Mandates SSP and POA&M documentation
- Enables CUI enclave scoping strategy
- Aligns with DFARS and CMMC compliance
Detailed Analysis
A comprehensive look at the specific requirements, scope, and impact of each standard.
ISO 27001 Details
What It Is
ISO/IEC 27001:2022 is the international certification standard for establishing, implementing, maintaining, and improving an Information Security Management System (ISMS). It uses a risk-based approach to manage information assets' confidentiality, integrity, and availability across all industries and sizes.
Key Components
- **Clauses 4-10Mandatory requirements for context, leadership, planning, support, operation, evaluation, improvement.
- **Annex A93 controls in four themes (Organizational 37, People 8, Physical 14, Technological 34).
- Built on PDCA cycle for continual improvement.
- Optional certification via accredited auditors.
Why Organizations Use It
- Enhances resilience against breaches, reduces costs (30% fewer incidents).
- Meets regulatory/contractual needs (GDPR, PCI-DSS alignments).
- Builds trust, wins bids (20-30% more in finance/tech).
- Provides competitive edge via certification signaling.
Implementation Overview
- Phased: Initiation, risk assessment, deployment (6-18 months).
- Scalable for SMEs to enterprises; involves gap analysis, SoA, audits.
- Certification: Stage 1 (docs), Stage 2 (effectiveness), annual surveillance.
NIST 800-171 Details
What It Is
NIST SP 800-171 Revision 3 is a U.S. government security framework providing recommended requirements for protecting Controlled Unclassified Information (CUI) confidentiality in nonfederal systems and organizations. It targets federal contractors and supply chains, using a control-based approach tailored from SP 800-53 Moderate baseline for risk-commensurate safeguards.
Key Components
- 97 requirements organized into 17 families (e.g., Access Control, Audit and Accountability, Supply Chain Risk Management).
- Core artifacts: System Security Plan (SSP) describing implementation, Plan of Action and Milestones (POA&M) for gaps.
- Built on FIPS 200; companion SP 800-171A r3 for assessments (examine/interview/test).
- Compliance via self-assessment, CMMC Level 2 certification.
Why Organizations Use It
- Meets contractual mandates like DFARS 252.204-7012.
- Reduces CUI breach risks, ensures DoD eligibility via SPRS scoring.
- Enhances cybersecurity maturity, builds stakeholder trust.
Implementation Overview
Phased: scoping CUI boundaries, gap analysis, control deployment, evidence collection. Applies to contractors handling CUI; suitable for all sizes, U.S.-focused. Requires audits for high-assurance (e.g., C3PAO).
Key Differences
| Aspect | ISO 27001 | NIST 800-171 |
|---|---|---|
| Scope | Comprehensive ISMS for all information assets | CUI confidentiality in nonfederal systems |
| Industry | All industries, global applicability | US federal contractors, defense supply chain |
| Nature | Voluntary international certification standard | Contractual US government security requirements |
| Testing | Accredited external audits, certification | Self-assessments, C3PAO audits, SPRS scoring |
| Penalties | Loss of certification, market access issues | Contract ineligibility, DoD procurement disqualification |
Scope
Industry
Nature
Testing
Penalties
Frequently Asked Questions
Common questions about ISO 27001 and NIST 800-171
ISO 27001 FAQ
NIST 800-171 FAQ
You Might also be Interested in These Articles...

CMMC Level 3 Implementation Guide: Integrating NIST SP 800-172 Enhanced Controls for APT Defense
Step-by-step CMMC Level 3 guide for DIB contractors. Implement 24 NIST SP 800-172 controls on Level 2. Prep for DIBCAC, C3PAO scoping & 180-day POA&Ms. Boost cy

Top 10 Cost-Saving Hacks for CMMC Compliance: Budgeting Blueprints for Small DIB Suppliers
Slash CMMC costs 30-50% with top 10 hacks for small DIB suppliers. Enclave scoping, FedRAMP clouds, automation, POA&M tips & budgeting blueprints for Level 2 co

NIST CSF 2.0 Supply Chain Risk Management: Complete Playbook with Profiles, Tiers, and Vendor Assessment Templates
Master NIST CSF 2.0 ID.SC supply chain risk management with vendor assessment templates, profile gap analysis, and tier strategies. Mitigate third-party threats
Run Maturity Assessments with GRADUM
Transform your compliance journey with our AI-powered assessment platform
Assess your organization's maturity across multiple standards and regulations including ISO 27001, DORA, NIS2, NIST, GDPR, and hundreds more. Get actionable insights and track your progress with collaborative, AI-powered evaluations.
Check out these other Gradum.io Standards Comparison Pages
SAFe vs MAS TRM
Compare SAFe vs MAS TRM: Agile scaling powerhouse meets Singapore's tech risk guidelines. Boost enterprise agility, compliance & ROI in regulated IT—explore now!
ISO 9001 vs WELL
Discover ISO 9001 vs WELL: Compare QMS excellence for operational efficiency with health-focused building standards. Boost compliance, performance & well-being now!
EPA vs FDA 21 CFR Part 11
EPA vs FDA 21 CFR Part 11: Compare environmental standards (CAA/CWA/RCRA) with electronic records rules. Master audits, permits, data integrity for compliance success. Expert insights now!