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ISO 27001 Secure Systems Architecture and Engineering Principles Explained

Last updated Jul 5, 2025

Author: Stuart Barker, ISO 27001 expert, thought leader and your number 1 source for everything ISO 27001.

ISO 27001 Secure Systems Architecture Explained with examples and ISO 27001 templates. Everything you need to know.

ISO 27001 Secure Systems Architecture and Engineering Principles

ISO 27001 Secure Systems Architecture and Engineering Principles mandates the implementation of secure system architecture and engineering principles. This involves designing security into all layers of the system throughout the development lifecycle. Furthermore, it emphasises “security by design and default.”

This is a preventive control designed to ensure information systems are designed, implemented, and operated securely throughout their lifecycle.

Who owns it?

The Chief Information Security Officer (CISO) is responsible for establishing, maintaining, and implementing the principles that govern the secure engineering of information systems, in collaboration with the development team.

ISO 27001 Toolkit

Compliance Guidance

The following is compliance guidance for Secure Systems Architecture and Engineering Principles.

1. Foundation

Establish, document, and apply robust security engineering principles throughout all stages of information system development.
Integrate security considerations into all architectural layers (business, data, applications, and technology).
Analyse new technologies for security risks and review designs against known attack patterns.

2. Core Principles

Guide user authentication, secure session management, data validation, and sanitisation.

3. Analyse

  • The full range of security controls needed to protect information and systems.
  • The capabilities of security controls to prevent, detect, and respond to security events.
  • Specific security controls required by business processes (e.g., encryption, integrity checks, digital signatures).
  • How security controls are integrated within the security architecture and technical infrastructure.
  • The interplay of individual security controls (manual and automated).

4. Key Considerations

  • Integrate with a defined security architecture.
  • Consider relevant security infrastructure (e.g., PKI, IAM, DLP, dynamic access management).
  • Evaluate the organisation’s capability to develop and support chosen technologies.
  • Assess the cost, time, and complexity of implementing security requirements.
  • Adhere to current best practices.

5. Core Engineering Practices

  • Apply security architecture principles: “security by design,” “defence in depth,” “security by default,” “default deny,” “fail securely,” “distrust external inputs,” “security in deployment,” “assume breach,” “least privilege,” “usability and manageability,” and “least functionality.”
  • Conduct thorough security-oriented design reviews to identify vulnerabilities and ensure security control effectiveness.
  • Document and address any exceptions to security requirements.
  • Implement system hardening measures.

6. Zero Trust Principles

  • Assume that the organisation’s systems are already compromised.
  • Employ a “never trust, always verify” approach to all access requests.
  • Encrypt all data in transit and at rest.
  • Verify all requests as if they originate from an untrusted source, regardless of internal or external origin.
  • Implement least privilege and dynamic access control based on context (user identity, device, data classification).
  • Enforce strong authentication (e.g., multi-factor authentication).

7. Outsourcing Considerations

  • Incorporate security engineering principles into contracts with third-party suppliers.
  • Ensure that suppliers’ security practices align with the organisation’s requirements.

8. Continuous Improvement:

  • Regularly review and update security engineering principles to address emerging threats and technologies.

Supplementary Guidance

Secure Engineering Principles can be applied to various techniques, including:

  • Fault Tolerance and Resilience: Implementing mechanisms to ensure system availability and data integrity in the face of failures or disruptions.
  • Segregation: Employing techniques like virtualisation or containerisation to isolate applications and prevent interference between them.
  • Tamper Resistance: Implementing measures to detect and prevent unauthorised modifications to data or systems.

1. Virtualisation for Enhanced Security

Virtualisation can enhance security by isolating applications within separate virtual environments. If one application is compromised, the impact on other applications and data is minimised.

2. Tamper Resistance Techniques

Tamper resistance techniques can detect and record attempts to modify data or systems. These techniques can be applied to both physical and logical containers.

ISO 27001 Secure Development Policy Template

The following is a fully ISO 27001 compliant ISO 27001 Secure Development Policy Template.

ISO 27001 Secure Development Policy Template

Further Reading

ISO 27001 Annex A 8.27 Secure Systems Architecture and Engineering Principles specifically addresses the requirements of Secure Systems Architecture and Engineering Principles.

ISO 27001 Secure Development Policy Template

ISO 27001 Clauses

ISO 27001 Clause 4.1 – Understanding The Organisation And Its Context

ISO 27001 Clause 4.2 – Understanding The Needs And Expectations of Interested Parties

ISO 27001 Clause 4.3 – Determining The Scope Of The Information Security Management System

ISO 27001 Clause 4.4 – Information Security Management System

ISO 27001 Clause 5.1 – Leadership and Commitment

ISO 27001 Clause 5.3 – Organisational Roles, Responsibilities and Authorities

ISO 27001 Clause 6.1.1 – Planning General

ISO 27001 Clause 6.1.2 – Information Security Risk Assessment

ISO 27001 Clause 6.1.3 – Information Security Risk Treatment

ISO 27001 Clause 6.2 – Information Security Objectives and Planning to Achieve Them

ISO 27001 Clause 6.3 – Planning Of Changes

ISO 27001 Clause 7.1 – Resources

ISO 27001 Clause 7.2 – Competence

ISO 27001 Clause 7.3 – Awareness

ISO 27001 Clause 7.4 – Communication

ISO 27001 Clause 7.5.1 – Documented Information

ISO 27001 Clause 7.5.2 – Creating and Updating Documented Information

ISO 27001 Clause 8.3 – Information Security Risk Treatment

ISO 27001 Clause 9.1 – Monitoring, Measurement, Analysis, Evaluation

ISO 27001 Clause 9.2 – Internal Audit

ISO 27001 Clause 9.3 – Management Review

ISO 27001 Clause 10.1 – Continual Improvement

ISO 27001 Clause 10.2 – Nonconformity and Corrective Action

ISO 27001 Organisation Controls

ISO 27001 Annex A 5.1: Policies for information security

ISO 27001 Annex A 5.2: Information Security Roles and Responsibilities

ISO 27001 Annex A 5.3: Segregation of duties

ISO 27001 Annex A 5.4: Management responsibilities

ISO 27001 Annex A 5.5: Contact with authorities

ISO 27001 Annex A 5.6: Contact with special interest groups

ISO 27001 Annex A 5.7: Threat intelligence

ISO 27001 Annex A 5.8: Information security in project management

ISO 27001 Annex A 5.9: Inventory of information and other associated assets

ISO 27001 Annex A 5.10: Acceptable use of information and other associated assets

ISO 27001 Annex A 5.11: Return of assets

ISO 27001 Annex A 5.12: Classification of information

ISO 27001 Annex A 5.13: Labelling of information

ISO 27001 Annex A 5.14: Information transfer

ISO 27001 Annex A 5.15: Access control

ISO 27001 Annex A 5.16: Identity management

ISO 27001 Annex A 5.17: Authentication information

ISO 27001 Annex A 5.18: Access rights

ISO 27001 Annex A 5.19: Information security in supplier relationships

ISO 27001 Annex A 5.20: Addressing information security within supplier agreements

ISO 27001 Annex A 5.21: Managing information security in the ICT supply chain

ISO 27001 Annex A 5.22: Monitoring, review and change management of supplier services

ISO 27001 Annex A 5.23: Information security for use of cloud services

ISO 27001 Annex A 5.24: Information security incident management planning and preparation

ISO 27001 Annex A 5.25: Assessment and decision on information security events

ISO 27001 Annex A 5.26: Response to information security incidents

ISO 27001 Annex A 5.27: Learning from information security incidents

ISO 27001 Annex A 5.28: Collection of evidence

ISO 27001 Annex A 5.29: Information security during disruption

ISO 27001 Annex A 5.30: ICT readiness for business continuity

ISO 27001 Annex A 5.31: Identification of legal, statutory, regulatory and contractual requirements

ISO 27001 Annex A 5.32: Intellectual property rights

ISO 27001 Annex A 5.33: Protection of records

ISO 27001 Annex A 5.34: Privacy and protection of PII

ISO 27001 Annex A 5.35: Independent review of information security

ISO 27001 Annex A 5.36: Compliance with policies and standards for information security

ISO 27001 Annex A 5.37: Documented operating procedures

About the author

Stuart Barker is an information security practitioner of over 30 years. He holds an MSc in Software and Systems Security and an undergraduate degree in Software Engineering. He is an ISO 27001 expert and thought leader holding both ISO 27001 Lead Implementer and ISO 27001 Lead Auditor qualifications. In 2010 he started his first cyber security consulting business that he sold in 2018. He worked for over a decade for GE, leading a data governance team across Europe and since then has gone on to deliver hundreds of client engagements and audits.

He regularly mentors and trains professionals on information security and runs a successful ISO 27001 YouTube channel where he shows people how they can implement ISO 27001 themselves. He is passionate that knowledge should not be hoarded and brought to market the first of its kind online ISO 27001 store for all the tools and templates people need when they want to do it themselves.

In his personal life he is an active and a hobbyist kickboxer.

His specialisms are ISO 27001 and SOC 2 and his niche is start up and early stage business.