How does ISO/IEC 27005 support ISO/IEC 27001 compliance?

ISO/IEC 27005 provides detailed guidance on performing information security risk assessments and treatments required by ISO/IEC 27001. It explains how to meet Clause 6.1.2 by defining context, evaluating risks, and selecting controls in a structured, auditable way.

ISO/IEC 27005 supports ISO/IEC 27001 by explaining how organizations should conduct information security risk management activities required for certification. While ISO/IEC 27001 states what must be done, ISO/IEC 27005 describes how to do it in a consistent and defensible manner.

Auditors increasingly scrutinize risk assessment quality, not just its existence. Between 2024 and 2025, many ISO/IEC 27001 nonconformities relate to weak risk evaluation logic, unclear acceptance criteria, or poor linkage between risks and controls. ISO/IEC 27005 addresses these gaps directly.

ISO/IEC 27001 Clause 6.1.2 requires organizations to identify risks, analyze and evaluate them, and define treatment options. ISO/IEC 27005 expands on each of these steps, including:

  • Context establishment and scope definition
  • Risk identification based on assets, threats, and vulnerabilities
  • Risk analysis using qualitative or quantitative techniques
  • Risk evaluation against defined acceptance criteria
  • Risk treatment and residual risk acceptance


Organizations using ISO/IEC 27005 typically produce clearer risk registers, better justified Statements of Applicability, and more consistent audit evidence. Risk decisions are traceable, repeatable, and aligned with business objectives rather than driven solely by control checklists.


Professionals responsible for ISO/IEC 27001 maintenance often use ISO/IEC 27005 as their internal risk methodology reference.

Related Information

  • ISO/IEC 27005 is a guidance standard, not a certifiable one.
  • ISO/IEC 27001 certification does not require formal adoption of ISO/IEC 27005, but auditors often expect alignment.
  • Risk acceptance criteria should be approved by management.
  • Risk treatment plans must reference implemented or planned controls.
  • ISO/IEC 27005 aligns with ISO 31000 risk principles.

Expert Insight

We regularly see organizations pass ISO/IEC 27001 initially, then struggle during surveillance audits because risk management was rushed. ISO/IEC 27005 helps prevent that by forcing clarity early: what is in scope, how risk is measured, and who accepts it. Mature organizations revisit these elements annually, not just before audits. The real benefit is stability. Once risk logic is defined, updates become incremental rather than disruptive.

“When auditors ask ‘why did you choose this control,’ ISO 27005 gives you a documented answer instead of a guess.”

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Topics

ISO 27001 RiskISO 27005 MethodologyISMS ImplementationISMSCompliance

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