ISO 27001:2022 Annex A Control 5.9 (A.5.9)

Explaining Control 5.9 (A.5.9) Inventory of information and other associated assets

ISO 27001 Annex A Control 5.9 emphasizes the importance of identifying and documenting all information and associated assets within your organization. By building and maintaining an accurate inventory, you ensure that each asset’s security needs are addressed and that asset ownership is clearly assigned. This control contributes to organized asset management and helps you make informed decisions about protection measures and risk management.

Control Type

Information Security Properties

Cybersecurity Concepts

Operational Capabilities

Security Domains

Objective of Control 5.9

The objective of Control 5.9 is to establish a structured approach to cataloging all relevant information and associated assets. Your organization benefits from clearly knowing what assets it has and who is responsible for those assets. An accurate, up-to-date inventory supports security decisions, promotes accountability, and enables efficient responses to incidents or audits.

Purpose of Control 5.9

The purpose of this control is to help you identify every information-bearing asset and associated resource so it can be properly classified, protected, and monitored. Through assigning ownership to each asset, you can establish responsibilities for safeguarding sensitive data and ensuring effective security controls throughout the asset’s life cycle. The inventory process also lays a foundation for managing risks associated with each asset.

Scope and Applicability

This control applies to a wide range of assets that your organization may use or manage. These include information assets, hardware, software, virtual machines, facilities, personnel competencies, and documented records. The level of detail in the inventory depends on the complexity of your organization and the potential impact if assets are compromised. Temporary or short-lived resources, such as virtual instances, should still be considered, but they can be documented in a way that reflects their short usage duration.

Inventory Management and Maintenance

Identification of Assets

Your organization should begin by listing all assets that create, store, process, or transmit information. This list can include:

Hardware devices like servers, desktops, and mobile devices
Software tools and applications
Information repositories (databases, document repositories)
Cloud-based resources, including virtual machines and storage buckets
Physical records or facilities hosting information

To keep the list relevant, focus on assets that significantly affect the confidentiality, integrity, or availability of data.

Documentation of Assets

Document assets in a consistent format. This may include fields such as:

Unique asset identifier
Asset name and description
Location or environment
Classification level (based on sensitivity)
Assigned owner (individual or group)
Purchase or creation date, if applicable
Planned review date for relevance and accuracy

Maintaining clear documentation allows your organization to track changes and assess risks more accurately.

Regular Reviews and Updates

Regular reviews are necessary to keep the asset inventory accurate. Your organization can conduct periodic validation exercises, such as:

Comparing physical or digital asset lists with inventory records
Incorporating inventory checks into change management processes
Leveraging automated discovery tools to identify new or modified assets

These actions help you detect discrepancies early and ensure the inventory remains reliable.

Consistency and Alignment

An organized approach to inventory management requires consistent classification and alignment across different departments. If various teams maintain separate records, coordinate with them to ensure all inventories share compatible fields and definitions. This avoids duplication and streamlines reporting during audits or risk assessments.

Ownership and Responsibilities

Assignment of Ownership

Each asset should have a clearly assigned owner who is accountable for its security throughout its life cycle. Ownership is assigned when assets are created or brought into your organization. It should be reassigned as roles change or when owners leave.

Owner Duties

Asset owners are responsible for:

Ensuring the asset is included and updated in the inventory.
Reviewing and assigning the proper classification level.
Reviewing classification periodically to maintain alignment with business needs.
Establishing acceptable use guidelines for the asset.
Restricting access based on the asset’s classification level and reviewing these restrictions periodically.
Overseeing secure disposal or archival of the asset when it is no longer needed, removing it from the inventory.
Managing risks linked to their assigned assets.
Supporting personnel who need specific information about the asset for operational or compliance reasons.

Classification Alignment

Your organization’s classification scheme (such as “Confidential,” “Internal Use Only,” “Public”) should apply to each asset in the inventory. Control 5.9 supports consistent labeling and handling of data. The classification should guide how you deploy protective measures, grant user permissions, and audit access logs. An accurate classification ensures that resources allocated to asset protection align with the asset’s sensitivity.

Ensuring Accuracy and Reliability

Verification Mechanisms

A reliable asset inventory can be maintained through verification processes, such as:

Scheduled checks against physical and virtual resources.
Automated asset discovery and monitoring tools.
Integration with configuration management databases or systems.

Granularity Considerations

Determine the necessary level of detail for each asset type. Critical systems that store sensitive data may require detailed entries, including software components, system configurations, and dependencies. For shorter-lived assets, document essential details sufficient for risk management without creating excessive administrative overhead.

Integration with Other Processes

Risk Management

An accurate inventory helps you identify threat exposures and prioritize risk treatment efforts. You can more effectively apply controls and allocate resources where they are needed most.

Incident Response

When an incident occurs, your organization can quickly identify the affected assets, locate the relevant owner, and determine the classification of any involved data. This improves the speed and efficiency of your incident handling and reduces potential impacts on operations.

Audit and Compliance

Many audits require proof that your organization manages its assets systematically. An up-to-date asset inventory demonstrates your commitment to sound security practices. It also helps you comply with various regulatory and industry requirements, reducing the risk of penalties.

Other Relevant Controls

Control 5.10: Acceptable Use of Assets
This control outlines policies and procedures for how employees, contractors, or third parties should interact with organizational assets in day-to-day operations.

Control 5.12: Classification of Information
This control helps define how information is categorized based on sensitivity and defines the standards for handling different classes of information.

Control 5.13: Handling of Assets
This control covers best practices for labeling, transporting, and disposing of information-bearing assets, ensuring continuity in their management life cycle.

Other controls may apply depending on your organization’s context, especially those related to access control, physical security, and incident management.

Templates That May Assist with This Control

Your organization can benefit from standardized documents or spreadsheet templates to maintain a consistent approach. Useful templates can include:

Asset Inventory Template: Provides a structured format for listing hardware, software, and information assets.
Asset Classification Guideline: Assists owners in determining the right classification for each asset.
Ownership Assignment Matrix: Helps define accountability by mapping asset types to specific owners.
Asset Review Checklist: Provides a step-by-step process for validating inventory data on a regular schedule.

Implementation Steps and Best Practices

1. Plan

Define the scope and objectives: Determine which areas of your organization’s operations will be covered by the asset inventory. Decide whether you will include all hardware, software, physical records, and virtual assets in one comprehensive list or create separate inventories for each category.
Identify stakeholders: Involve representatives from different departments to ensure you capture all assets. Departments like IT, finance, operations, and HR may have their own inventories or unique asset types. Assign clear roles and responsibilities for collecting data and maintaining the inventory.
Establish a governance structure: Designate a project lead or steering committee to oversee the entire inventory process. Define reporting lines to ensure any issues or updates are communicated efficiently to management.

2. Execute

Gather asset information: Use standardized templates, discovery tools, or spreadsheets to collect data. Document details like asset name, category, owner, classification, and other relevant attributes. Encourage each department to conduct an initial identification of assets and consolidate findings into a central repository.
Coordinate with asset owners: When assigning ownership, confirm that each individual or team understands their responsibilities. Provide guidelines for how to classify assets and maintain ongoing updates, especially for assets in dynamic environments such as cloud-based services.
Validate and reconcile: Cross-check existing records or inventories to ensure you have an accurate baseline. Compare department-level lists with centralized data to identify duplicates or missing entries.

3. Review and Refine

Establish review intervals: Define a review schedule (e.g., quarterly or semi-annually) for asset owners and department heads to verify the accuracy of the inventory. This can include checking if any assets are missing, obsolete, or have changed status (e.g., location, ownership).
Adjust classification where needed: Over time, the sensitivity or business impact of certain assets may change. Periodically re-evaluate asset classifications to ensure the level of protection remains appropriate.
Track decommissioned or retired assets: Ensure retired assets are removed from active inventory or moved to a separate archive. Confirm that any sensitive data is wiped or destroyed in a secure manner, following your organization’s data disposal and retention policies.

4. Integrate with Security Processes

Link to risk assessments: Incorporate asset inventory checks into your risk assessment activities. When you identify a vulnerability or potential threat, refer to the asset inventory to see which assets might be at risk and how that risk could affect broader business operations.
Merge with incident response procedures: Make sure the inventory is easily accessible to your incident response team. Quick access to accurate asset details helps determine how an incident might spread and which data might be at risk.
Align with change management: Update the asset inventory as part of any change or configuration management process. When new software is installed, systems are upgraded, or equipment is replaced, ensure that the inventory reflects these changes in real time.

5. Automate Where Possible

Asset discovery tools: Consider using specialized software to automatically detect new hardware and software on the network. Automated discovery can reveal unauthorized or forgotten assets and reduce manual tracking effort.
Configuration management databases: Integrate the inventory with a centralized configuration management database (CMDB) to store configurations, relationships, and dependencies among assets. This approach helps you see the impact of changes on interconnected systems.
Ongoing monitoring: Deploy monitoring systems that continuously track hardware, software versions, and application usage. Automated alerts or reporting capabilities can notify you when an asset changes state (e.g., new installation, decommissioning), prompting immediate updates to the inventory.

Conclusion

ISO 27001 Control 5.9 offers a framework for building and maintaining a reliable inventory of information and associated assets. Via keeping this inventory accurate, assigning ownership, and aligning asset classification with organizational requirements, your organization can strengthen security and efficiently address potential risks. This control helps ensure that each asset is adequately protected and that the assigned owner has the necessary information to manage the asset securely. Regular updates, periodic audits, and alignment with related controls enable a continuous process of improvement in asset management and overall security posture.