ISO 27001:2022 Annex A 8.26 – Application Security Requirements Explained

Applications are where data is processed, decisions are made, and money often changes hands.
If application security is weak, every upstream control is undermined.

Annex A 8.26 exists to ensure organisations define and apply appropriate information security requirements for applications, whether they are developed in-house, purchased, customised, or provided as a service.

This control is about making security a defined requirement of applications — not an afterthought.

ISO 27001

Quick Guide: Annex A 8.26 at a Glance

Annex A 8.26 of ISO 27001:2022 focuses on application security requirements.

At a practical level, this means:

  • Defining security requirements for applications based on risk
  • Protecting information processed, stored, or transmitted by applications
  • Addressing access control, integrity, confidentiality, and availability
  • Considering legal, regulatory, and contractual obligations
  • Applying security requirements throughout the application life cycle

The control does not prescribe specific technologies. It expects clear, risk-based requirements that are deliberately applied and maintained.

In-Depth Guide to Annex A 8.26

What Is Annex A 8.26 and Why Does It Matter?

Applications are frequently the primary cause of:

  • Data breaches
  • Privacy incidents
  • Fraud
  • Service disruption

This is because applications:

  • Process sensitive information
  • Interface with users, partners, and the internet
  • Rely on complex logic and dependencies
  • Are frequently changed

If security requirements are not clearly defined:

  • Applications behave inconsistently
  • Controls are applied unevenly
  • Vulnerabilities are introduced by design
  • Compliance becomes accidental

Annex A 8.26 ensures organisations know what security an application is expected to provide — and why.

This control replaces ISO 27001:2013 Annex A 14.1.2 and 14.1.3, expanding the scope from public network applications to all applications.

How to Implement Annex A 8.26 Effectively

A pragmatic approach to Annex A 8.26 typically includes the following elements.

1. Define Application Security Requirements Based on Risk

Organisations should determine security requirements by considering:

  • Information sensitivity
  • Business criticality
  • Exposure to users and networks
  • Likelihood and impact of compromise

Requirements should be risk-driven, not copied blindly across all systems.

2. Identify Information Assets Processed by the Application

Security requirements should reflect:

  • Classification of information handled
  • Whether personal, confidential, or regulated data is involved
  • Data creation, processing, storage, and output

Applications that process sensitive data require stronger controls by design.

3. Define Trust and Identity Requirements

Applications should clearly define:

  • How users and systems are identified
  • Required levels of trust
  • How identity assurance is achieved

This aligns closely with:

  • Identity and access management
  • Privileged access controls
  • Authentication strength requirements

Weak identity assurance undermines all other controls.

4. Control Access to Application Functions and Data

Annex A 8.26 supports defining:

  • Who can access the application
  • Which functions each role can use
  • What data each role can view or change

Access should follow:

  • Least privilege
  • Separation of duties where required

Function-level access control is as important as application-level access.

5. Protect Information Confidentiality, Integrity, and Availability

Application security requirements should address:

  • Protection of data at rest
  • Protection of data in transit
  • Prevention of unauthorised modification
  • Availability and resilience expectations

Cryptographic controls may be required where risk justifies it.

6. Address Input, Processing, and Output Controls

Applications should define requirements for:

  • Input validation and integrity checking
  • Automated processing controls
  • Output controls, including who can view results

Free-text input fields should be controlled to prevent:

  • Accidental disclosure
  • Injection attacks
  • Data integrity issues

Unchecked input is one of the most common application weaknesses.

7. Define Logging and Non-Repudiation Requirements

Where appropriate, applications should:

  • Log relevant transactions and events
  • Support traceability and accountability
  • Provide evidence for investigation or dispute resolution

This is particularly relevant for:

  • Financial transactions
  • Regulatory reporting
  • High-risk operational processes
8. Address Error Handling and Messaging

Error messages should be designed to:

  • Support troubleshooting
  • Avoid revealing sensitive information
  • Prevent attackers gaining insight into application logic

Helpful to users does not mean helpful to attackers.

9. Consider Legal, Regulatory, and Contractual Requirements

Application security requirements should reflect:

  • Data protection and privacy legislation
  • Sector-specific regulation
  • Contractual obligations
  • Retention and evidential requirements

Compliance obligations should be built into application behaviour, not bolted on later.

10. Define Requirements for Transactional Services

Where applications support transactions with external parties, requirements should consider:

  • Trust in counterpart identities
  • Integrity and authenticity of transactions
  • Authorisation and approval mechanisms
  • Confidentiality of transaction data
  • Retention and dispute requirements

Transactional failures often become legal failures.

11. Define Requirements for Electronic Ordering and Payment

For ordering and payment applications, organisations should consider:

  • Confidentiality and integrity of order data
  • Confirmation and validation of payment information
  • Prevention of duplication or loss of transactions
  • Protection of transaction data from public exposure
  • Secure use of digital signatures where applicable

Payment systems magnify the impact of design weaknesses.

12. Apply Security Requirements Across the Application Life Cycle

Security requirements should apply during:

  • Development and configuration
  • Acquisition and procurement
  • Operation and maintenance
  • Change and enhancement

This aligns directly with the secure development life cycle (Annex A 8.25).

In-Depth Guide to Annex A 5.1

What is Annex A 5.1 and Why Does It Matter?

  • What the organisation values
  • How security decisions are approached
  • Where accountability sits
  • Aligns security with business objectives
  • Supports proportionate, risk-based decisions
  • Provides a reference point during incidents and disputes
  • Creates consistency without bureaucracy

How to Implement Annex A 5.1 Effectively

1. Define a Comprehensive Information Security Policy
  • Scope: What the policy applies to (systems, data, people).
  • Objectives: Why security is important for the business.
  • Roles & Responsibilities: Who is accountable for security.
  • Key Principles: Risk management, access control, and data protection.
2. Secure Senior Management Approval
  • Review and approve policies.
  • Ensure resources are allocated for implementation.
  • Lead by example in enforcing security policies.
3. Communicate and Train Employees
  • Include security policies in onboarding and ongoing training.
  • Ensure policies are easily accessible to all employees.
  • Encourage acknowledgment and acceptance of security responsibilities.
4. Regular Review & Continuous Improvement
  • Set a schedule for periodic policy reviews (at least annually).
  • Update policies based on business changes, new threats, or regulatory updates.
  • Conduct audits to ensure compliance and effectiveness.
5. Integrate Policies into the ISMS
  • Use it to develop more detailed security procedures.
  • Ensure policies align with other Annex A controls and broader risk management practices.
Key Differences: ISO 27001:2013 vs ISO 27001:2022
AspectISO 27001:2013ISO 27001:2022
Control StructureTwo separate controls: 5.1.1 & 5.1.2Merged into one control (5.1)
Implementation GuidanceLess prescriptiveMore detailed guidance for policy creation and alignment
Awareness & TrainingNot explicitly mentionedExplicitly requires policies to be part of training programmes
Attributes TableNot includedew attributes table for mapping policies to industry terms
Common Challenges & How to Overcome Them
  • Challenge: Employees don’t follow security policies.
  • Solution: Make policies practical and relevant to daily work. Use real-world examples in training.
  • Challenge: Policies are outdated or too generic.
  • Solution: Schedule annual reviews and update policies based on real threats and business changes.
  • Challenge: Policies are written in technical jargon.
  • Solution: Use plain language that all employees can understand.
  • Challenge: Lack of leadership buy-in.
  • Solution: Show how weak security affects business objectives—costs of breaches, loss of client trust, and legal penalties.
Final Recommendations
  • Make security policies living documents—review, refine, and update regularly.
  • Use policy training and awareness to create a security-conscious workforce.
  • Ensure policies are accessible, relevant, and easy to understand.
  • Keep policies aligned with business strategy and regulatory requirements.
  • Engage leadership in driving security culture from the top down.

Practical Considerations

Annex A 8.26 does not require:

  • Identical security requirements for all applications
  • Custom development of every control
  • Reinventing existing secure platforms

It does require organisations to:

  • Define what “secure enough” means for each application
  • Apply those requirements consistently
  • Be able to justify decisions

Undefined security requirements are indistinguishable from no requirements.

Common Challenges and How to Overcome Them

  • Assuming vendors handle application security
  • Define and verify security requirements explicitly
  • Security added late in the process
  • Define requirements before development or procurement
  • Inconsistent controls across applications
  • Use risk-based security requirement frameworks
  • Ignoring transaction and payment risks
  • Apply specific requirements for high-risk functionality

Most application failures are requirement failures.

In-Depth Guide to Annex A 5.1

What is Annex A 5.1 and Why Does It Matter?

  • What the organisation values
  • How security decisions are approached
  • Where accountability sits
  • Aligns security with business objectives
  • Supports proportionate, risk-based decisions
  • Provides a reference point during incidents and disputes
  • Creates consistency without bureaucracy

How to Implement Annex A 5.1 Effectively

1. Define a Comprehensive Information Security Policy
  • Scope: What the policy applies to (systems, data, people).
  • Objectives: Why security is important for the business.
  • Roles & Responsibilities: Who is accountable for security.
  • Key Principles: Risk management, access control, and data protection.
2. Secure Senior Management Approval
  • Review and approve policies.
  • Ensure resources are allocated for implementation.
  • Lead by example in enforcing security policies.
3. Communicate and Train Employees
  • Include security policies in onboarding and ongoing training.
  • Ensure policies are easily accessible to all employees.
  • Encourage acknowledgment and acceptance of security responsibilities.
4. Regular Review & Continuous Improvement
  • Set a schedule for periodic policy reviews (at least annually).
  • Update policies based on business changes, new threats, or regulatory updates.
  • Conduct audits to ensure compliance and effectiveness.
5. Integrate Policies into the ISMS
  • Use it to develop more detailed security procedures.
  • Ensure policies align with other Annex A controls and broader risk management practices.
Key Differences: ISO 27001:2013 vs ISO 27001:2022
AspectISO 27001:2013ISO 27001:2022
Control StructureTwo separate controls: 5.1.1 & 5.1.2Merged into one control (5.1)
Implementation GuidanceLess prescriptiveMore detailed guidance for policy creation and alignment
Awareness & TrainingNot explicitly mentionedExplicitly requires policies to be part of training programmes
Attributes TableNot includedew attributes table for mapping policies to industry terms
Common Challenges & How to Overcome Them
  • Challenge: Employees don’t follow security policies.
  • Solution: Make policies practical and relevant to daily work. Use real-world examples in training.
  • Challenge: Policies are outdated or too generic.
  • Solution: Schedule annual reviews and update policies based on real threats and business changes.
  • Challenge: Policies are written in technical jargon.
  • Solution: Use plain language that all employees can understand.
  • Challenge: Lack of leadership buy-in.
  • Solution: Show how weak security affects business objectives—costs of breaches, loss of client trust, and legal penalties.
Final Recommendations
  • Make security policies living documents—review, refine, and update regularly.
  • Use policy training and awareness to create a security-conscious workforce.
  • Ensure policies are accessible, relevant, and easy to understand.
  • Keep policies aligned with business strategy and regulatory requirements.
  • Engage leadership in driving security culture from the top down.

Final Recommendations

Annex A 8.26 is about making security a deliberate property of applications.

When application security requirements are defined and applied effectively:

  • Data protection improves
  • Compliance becomes predictable
  • Vulnerabilities are reduced by design
  • Assurance becomes demonstrable

Applications do not fail randomly.
They fail according to the requirements they were given.

Annex A 8.26 ensures organisations give them the right ones.

In-Depth Guide to Annex A 5.1

What is Annex A 5.1 and Why Does It Matter?

  • What the organisation values
  • How security decisions are approached
  • Where accountability sits
  • Aligns security with business objectives
  • Supports proportionate, risk-based decisions
  • Provides a reference point during incidents and disputes
  • Creates consistency without bureaucracy

How to Implement Annex A 5.1 Effectively

1. Define a Comprehensive Information Security Policy
  • Scope: What the policy applies to (systems, data, people).
  • Objectives: Why security is important for the business.
  • Roles & Responsibilities: Who is accountable for security.
  • Key Principles: Risk management, access control, and data protection.
2. Secure Senior Management Approval
  • Review and approve policies.
  • Ensure resources are allocated for implementation.
  • Lead by example in enforcing security policies.
3. Communicate and Train Employees
  • Include security policies in onboarding and ongoing training.
  • Ensure policies are easily accessible to all employees.
  • Encourage acknowledgment and acceptance of security responsibilities.
4. Regular Review & Continuous Improvement
  • Set a schedule for periodic policy reviews (at least annually).
  • Update policies based on business changes, new threats, or regulatory updates.
  • Conduct audits to ensure compliance and effectiveness.
5. Integrate Policies into the ISMS
  • Use it to develop more detailed security procedures.
  • Ensure policies align with other Annex A controls and broader risk management practices.
Key Differences: ISO 27001:2013 vs ISO 27001:2022
AspectISO 27001:2013ISO 27001:2022
Control StructureTwo separate controls: 5.1.1 & 5.1.2Merged into one control (5.1)
Implementation GuidanceLess prescriptiveMore detailed guidance for policy creation and alignment
Awareness & TrainingNot explicitly mentionedExplicitly requires policies to be part of training programmes
Attributes TableNot includedew attributes table for mapping policies to industry terms
Common Challenges & How to Overcome Them
  • Challenge: Employees don’t follow security policies.
  • Solution: Make policies practical and relevant to daily work. Use real-world examples in training.
  • Challenge: Policies are outdated or too generic.
  • Solution: Schedule annual reviews and update policies based on real threats and business changes.
  • Challenge: Policies are written in technical jargon.
  • Solution: Use plain language that all employees can understand.
  • Challenge: Lack of leadership buy-in.
  • Solution: Show how weak security affects business objectives—costs of breaches, loss of client trust, and legal penalties.
Final Recommendations
  • Make security policies living documents—review, refine, and update regularly.
  • Use policy training and awareness to create a security-conscious workforce.
  • Ensure policies are accessible, relevant, and easy to understand.
  • Keep policies aligned with business strategy and regulatory requirements.
  • Engage leadership in driving security culture from the top down.

The Annex Control Table

ISO 27001:2022 Organisational Controls
ISO 27001:2022 Technological Controls