ISO 27005 – Implementation Roadmap

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Status: Final Blueprint Summary

Author: Shahab Al Yamin Chawdhury

Organization: Principal Architect & Consultant Group

Research Date: August 21, 2024

Location: Dhaka, Bangladesh

Version: 1.0

1.0 Executive Summary & Strategic Imperative

This document provides a summarized blueprint for implementing the ISO/IEC 27005:2022 standard for information security risk management. The core objective is to transform risk management from a cost center into a strategic, value-generating function.

The Financial Imperative:

A robust risk management framework is a strategic necessity driven by severe financial consequences of security failures.

  • High Breach Costs: The global average cost of a data breach has reached USD 4.88 million. Costs are significantly higher in regulated industries like healthcare (USD 9.77 million) and finance (USD 6.08 million).
  • Human & Third-Party Factors: The human element is a factor in 68% of breaches, and incidents involving third parties have increased by 68%.
  • Key Threat Vectors: Stolen credentials remain the most common attack vector (16% of incidents), while ransomware and extortion are involved in approximately one-third of all breaches.

2.0 The ISO Framework Ecosystem

ISO 27005 operates within a symbiotic ecosystem of standards:

  • ISO 31000 (The Philosophy): Provides a high-level, generic framework for Enterprise Risk Management (ERM) across all risk domains.
  • ISO 27001 (The Mandate): The certifiable standard for an Information Security Management System (ISMS) that requires a formal risk assessment and treatment process.
  • ISO 27005 (The Methodology): Provides the detailed, step-by-step guidance on how to conduct the information security risk management mandated by ISO 27001.

3.0 The 4-Phase Implementation Roadmap

This roadmap outlines a continuous, four-phase lifecycle for implementing ISO 27005.

Phase 1: Context Establishment (Foundation)

This phase sets the strategic foundation and rules for the risk management program.

  • Key Activities:
    • Define the scope and boundaries of the risk management process.
    • Identify all internal and external stakeholders and their requirements.
    • Establish clear and objective risk criteria, including impact scales, likelihood scales, and the organization’s official risk appetite.
  • Key Deliverables:
    • Scope and Context Document
    • Risk Criteria Document

Phase 2: Information Security Risk Assessment (Discovery)

This phase involves the systematic identification, analysis, and evaluation of risks.

  • Key Activities:
    • Risk Identification (Dual-Pronged Approach):
      1. Asset-Based: Inventorying assets and identifying their associated threats and vulnerabilities.
      2. Event-Based: Developing plausible, threat-intelligence-informed risk scenarios (e.g., ransomware attack, insider threat).
    • Risk Analysis: Determine the level of each risk, preferably using a quantitative model like FAIR to express risk in financial terms (Annualized Loss Expectancy).
    • Risk Evaluation: Compare analyzed risks against the predefined acceptance criteria to prioritize them for treatment.
  • Key Deliverables:
    • Comprehensive Asset Register
    • Risk Scenario Library
    • Prioritized Risk Register

Phase 3: Information Security Risk Treatment (Action)

This phase translates analysis into a concrete action plan to address unacceptable risks.

  • Key Activities:
    • Select one of four risk treatment options for each prioritized risk: Modify (mitigate), Retain (accept), Avoid, or Share (transfer).
    • For risks being modified, conduct a cost-benefit analysis to ensure a positive Return on Security Investment (ROSI) for selected controls.
    • Formulate a detailed Risk Treatment Plan (RTP) documenting actions, responsibilities, timelines, and resources.
    • Develop the Statement of Applicability (SoA), a mandatory document for ISO 27001 that justifies the inclusion or exclusion of Annex A controls.
  • Key Deliverables:
    • Risk Treatment Plan (RTP)
    • Statement of Applicability (SoA)

Phase 4: The Continuous Lifecycle (Sustainability)

This phase ensures the risk management process is an ongoing and adaptive part of the organization’s operations.

  • Key Activities:
    • Risk Communication: Develop and execute a plan to communicate risk information to all relevant stakeholders.
    • Monitoring and Review: Continuously monitor for changes in the risk landscape and conduct formal reviews of the risk assessment annually or upon significant change.
    • Continual Improvement: Use monitoring outputs to update documentation and refine the ISMS, following the Plan-Do-Check-Act (PDCA) cycle.
  • Key Deliverables:
    • Risk Communication Plan
    • Risk Monitoring Reports
    • Updated Risk Documentation & Management Review Records

4.0 Critical Success Factors

  • Best Practices to Adopt:
    • Secure active executive sponsorship from the start.
    • Form a cross-functional team including representatives from legal, HR, finance, and business units.
    • Adopt a phased implementation, starting with a critical scope to demonstrate early success.
    • Foster a risk-aware culture through continuous training and communication.
  • Common Pitfalls to Avoid:
    • Lack of genuine executive buy-in and resource commitment.
    • Poorly defined scope (either too broad or too narrow).
    • Creating “paper-only” compliance documents that don’t reflect operational reality.
    • Underestimating the skills, resources, and administrative effort required.