ISO/IEC 27001

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Data Inventory Template

1. Purpose

The purpose of this Data Inventory Template is to help the organization identify, document, classify, understand, and manage the information and data it collects, processes, stores, transfers, shares, and deletes.

A data inventory helps the organization answer:

  • What data do we have?
  • Where does it come from?
  • Where is it stored?
  • Who uses it?
  • Why do we use it?
  • Who can access it?
  • Who do we share it with?
  • How long do we retain it?
  • What security protections are applied?
  • What risks and regulatory requirements apply?

The inventory should support both information security risk management and, where applicable, privacy and regulatory compliance.


2. Scope

The inventory may cover:

  • Customer data
  • Employee data
  • Applicant data
  • Supplier/vendor data
  • Financial information
  • Authentication information
  • Business information
  • Source code and technical information
  • Security logs
  • Audit information
  • Contracts
  • Marketing information
  • Support information
  • Application data
  • Database records
  • Cloud storage
  • Backup data
  • Data processed by SaaS applications
  • Data processed by third parties
  • Paper or physical records where relevant

The level of detail should be proportionate to the organization’s size, complexity, risks, and applicable requirements.


3. Data Inventory Record

Each significant data set or data category should have a record.

FieldDescription
Data IDUnique identifier
Data/Information NameName of the data set
Data CategoryCustomer, employee, financial, technical, etc.
DescriptionWhat the data contains
Business ProcessProcess using the data
Data OwnerPerson responsible for the data
System/ApplicationApplication processing the data
Storage LocationDatabase, cloud storage, SaaS, physical location, etc.
Data SourceWhere the data originates
Data Subjects/IndividualsCustomers, employees, suppliers, users, etc.
Information ClassificationPublic/Internal/Confidential/Restricted, or organizational scheme
Personal DataYes/No
Sensitive DataYes/No, based on applicable definition
Customer DataYes/No
Financial DataYes/No
Security/Credential DataYes/No
CriticalityCritical/High/Medium/Low
Confidentiality RequirementLow/Medium/High
Integrity RequirementLow/Medium/High
Availability RequirementLow/Medium/High
Processing PurposeWhy the data is used
Access RolesWho can access it
Privileged AccessYes/No
Internal SharingDepartments/users receiving data
External SharingThird parties receiving data
Third-Party ProcessorRelevant supplier
Data LocationCountry/region/cloud region
Data TransferCross-border transfer, if applicable
EncryptionAt rest/in transit/other
Authentication/Access ControlSecurity controls
Logging/MonitoringRelevant monitoring
BackupBackup requirements
Retention PeriodHow long data is retained
Disposal MethodHow data is deleted/destroyed
Related Asset IDLink to Asset Inventory
Related Risk IDLink to Risk Register
Related RequirementLegal/regulatory/contractual requirement
Related ControlRelevant security/privacy control
Last ReviewedDate
Next ReviewDate
StatusActive/Archived/Deleted/etc.
Evidence/ReferenceSupporting record

4. Data Categories

Organizations should define categories appropriate to their business.

Example

Data CategoryExamples
Customer DataCustomer name, account details, support information
Employee DataEmployee records, payroll information
Authentication DataUser IDs, authentication metadata
Financial DataInvoices, payment records
Technical DataIP addresses, system configurations
Security DataLogs, alerts, security events
Business DataContracts, proposals, business plans
Source CodeApplication source code and repositories
Supplier DataSupplier contacts and contracts
Marketing DataLeads, campaign information
Audit DataAudit evidence and assessment records

5. Data Classification

Each data set should be assigned an appropriate classification.

For example:

ClassificationTypical ExampleProtection
PublicPublic website contentBasic integrity protection
InternalInternal proceduresAuthorized employee access
ConfidentialCustomer informationRestricted access and appropriate encryption
RestrictedCredentials, encryption keysStrong access controls and enhanced protection

These classification levels are examples. The organization should define its own classification scheme and handling requirements.


6. Data Owner

Every important data set should have an accountable owner.

The Data Owner should be responsible for:

  • Understanding the purpose of the data.
  • Confirming business use.
  • Determining appropriate classification.
  • Identifying authorized users.
  • Supporting risk assessment.
  • Defining retention requirements.
  • Reviewing access requirements.
  • Supporting data deletion/archiving decisions.
  • Ensuring the inventory remains accurate.

The Data Owner does not necessarily perform the technical administration of the data.


7. Data Source

The organization should document where data originates.

Possible sources include:

  • Customer registration
  • Website forms
  • Mobile applications
  • APIs
  • Employees
  • Suppliers
  • Business partners
  • Public sources
  • Customer integrations
  • Internal systems
  • Cloud services
  • Third-party SaaS applications

Example

Customer email address

Source → Customer signup form
↓
Application → SaaS platform
↓
Database → AWS RDS
↓
Support → Customer support platform
↓
Backup → AWS backup environment


8. Data Flow

Where appropriate, document how important data moves through the organization.

A simple data flow may be:

Customer → Web Application → API → AWS Application → RDS → Backup → Support SaaS

For more sensitive or complex processing, maintain a formal Data Flow Diagram.

The data inventory should identify the relevant systems and services involved in the flow.


9. Data Storage Location

Record where data is stored.

Examples:

  • AWS RDS
  • Amazon S3
  • Azure SQL
  • Google Cloud Storage
  • Microsoft 365
  • GitHub
  • Salesforce
  • HR platform
  • Customer support platform
  • Employee laptop
  • Physical records

For cloud environments, consider recording:

  • Cloud provider
  • Account/subscription
  • Region
  • Service
  • Environment
  • Storage type

10. Data Processing Purpose

The organization should document why the data is processed.

Examples:

DataPurpose
Customer account informationProvide SaaS service
Customer support informationResolve support requests
Employee informationEmployment administration
Security logsSecurity monitoring and investigation
Payment informationBilling and payment processing
Marketing contact informationMarketing communications
Authentication informationUser authentication and account security

The purpose should be sufficiently specific to understand the business need.


11. Access and Use

Document who can access important data.

Example:

DataUsers/RolesAccess
Customer databaseEngineering/DBAPrivileged
Customer support dataSupport TeamBusiness access
Employee recordsHRRestricted
Security logsSecurity TeamRestricted
Source codeEngineeringAuthorized developers
Financial recordsFinanceRestricted

Access should follow:

Need-to-Know → Least Privilege → Authorized Access → Periodic Review


12. Data Sharing

Identify internal and external data sharing.

Internal Sharing

Examples:

  • Engineering
  • Finance
  • HR
  • Customer Support
  • Security
  • Management

External Sharing

Examples:

  • Cloud providers
  • SaaS providers
  • Payment providers
  • Auditors
  • Consultants
  • Customers
  • Regulators
  • Government authorities
  • Business partners

For significant third-party sharing, record the applicable supplier/security/privacy requirements.


13. Third-Party Data Processing

Where a supplier or service provider processes organizational data, record:

  • Supplier
  • Service
  • Data processed
  • Purpose
  • Data classification
  • Data location
  • Security assessment
  • Contract
  • Data processing agreement, where applicable
  • Incident notification requirements
  • Retention
  • Deletion/return requirements
  • Supplier review date

Example

Customer Support SaaS

Customer name, email address, support tickets and attachments
↓
Customer Support Platform
↓
Third-party processor
↓
Support team access

The SaaS Application Register and Supplier Security Assessment should contain the corresponding supplier information.


14. Data Location and Cross-Border Transfer

Where relevant, record where data is stored or processed.

Example:

DataProviderRegionCross-Border Processing
Customer DataAWSMumbaiNo
Customer SupportSaaS ProviderUnited StatesYes
Employee DataHR PlatformIndiaNo
Source CodeGitHubProvider-controlledReview required

Cross-border transfer requirements depend on the applicable laws, contractual commitments, data type, and jurisdictions involved.

The data inventory should therefore identify potential transfers rather than assuming that every transfer is prohibited or permitted.


15. Data Security Controls

For important data sets, record applicable security controls.

Examples include:

  • Encryption at rest
  • Encryption in transit
  • MFA
  • RBAC
  • Least privilege
  • Network restrictions
  • Backup
  • Logging
  • Monitoring
  • DLP
  • Data masking
  • Tokenization
  • Secure deletion
  • Vulnerability management
  • Access reviews

Example

Customer Database

Classification → Confidential
↓
Encryption → Enabled
↓
Access → RBAC
↓
Privileged Access → MFA
↓
Monitoring → CloudTrail/CloudWatch and database monitoring
↓
Backup → Automated backup
↓
Review → Periodic access/security review


16. Data Retention

The organization should define appropriate retention periods based on:

  • Business requirements
  • Legal requirements
  • Regulatory requirements
  • Contractual requirements
  • Security requirements
  • Operational requirements

Example:

DataRetentionReason
Customer account dataDefined by service/business requirementService delivery
Security logsDefined by security requirementsMonitoring/investigation
Employee recordsDefined by applicable requirementsEmployment administration
ContractsDefined by legal/business requirementsLegal/business record
Temporary filesShort-termOperational need

Retention periods should not be copied from generic templates without confirming their applicability.


17. Data Disposal

When data reaches the end of its retention period, the organization should determine whether it should be:

  • Deleted
  • Anonymized
  • Archived
  • Returned
  • Securely destroyed

Disposal should consider:

  • Primary systems
  • Backups
  • Replicas
  • Archives
  • SaaS platforms
  • Third-party processors
  • Physical media

Evidence may include:

  • Deletion logs
  • System records
  • Supplier deletion confirmation
  • Disposal certificates
  • Approved deletion tickets

18. Data Lifecycle

A practical data lifecycle is:

Collect/Create → Classify → Store → Use → Share → Monitor → Retain → Archive/Delete → Verify

For sensitive information:

Identify → Classify → Protect → Access → Monitor → Retain → Securely Dispose

The lifecycle should be connected to the organization’s asset lifecycle and information security processes.


19. AWS SaaS Example

Consider a SaaS company providing a customer analytics platform.

Data Set

Customer Account Data

FieldExample
Data IDDATA-001
DataCustomer account information
SourceCustomer registration
SystemSaaS application
StorageAWS RDS
ClassificationConfidential
OwnerCustomer Operations/Business Owner
Technical CustodianEngineering
CriticalityHigh
Personal DataYes, where applicable
AccessSupport + authorized operations
Privileged AccessEngineering/DBA
EncryptionEnabled
BackupAutomated
MonitoringSecurity monitoring
Third PartiesRelevant cloud/SaaS providers
RetentionDefined by applicable business/legal requirements
DisposalSecure deletion
Related RiskR-001
Related AssetAST-001
ReviewPeriodic

20. Data Inventory vs Asset Inventory

These records are related but serve different purposes.

Asset InventoryData Inventory
What assets exist?What data exists?
ServersCustomer data
ApplicationsEmployee data
Cloud resourcesFinancial data
LaptopsSecurity logs
SaaS applicationsSupport information
Network infrastructureSource/business information
Security systemsPersonal/sensitive information

Example:

Asset: AWS RDS database
Data: Customer account information stored in that database

Therefore:

Data → Stored/Processed by Asset → Protected by Controls


21. Data Inventory and Risk Management

The Data Inventory should feed into the organization’s risk management process.

Example:

Customer Data
↓
Stored in AWS RDS
↓
Confidential
↓
Unauthorized access risk
↓
MFA + RBAC + encryption + monitoring + access reviews
↓
Risk Register
↓
Risk treatment
↓
Evidence

This helps ensure that security controls are based on actual information and business risks.


22. Data Inventory and Privacy

Where personal data is involved, the Data Inventory can support privacy activities such as:

  • Data mapping
  • Records of processing
  • Privacy impact assessments
  • Data subject rights processes
  • Retention management
  • Processor management
  • Data transfer assessments
  • Breach response
  • Privacy notices

However, a Data Inventory is not automatically the same thing as a Record of Processing Activities (RoPA).

A RoPA may require additional privacy-specific information depending on the applicable law.


23. Data Inventory Review Process

The inventory should be reviewed:

  • Periodically
  • When new applications are introduced
  • When new data is collected
  • When business processes change
  • When systems are migrated
  • When suppliers change
  • When data locations change
  • After significant incidents
  • When legal/regulatory requirements change
  • Before retiring significant systems

Review Workflow

Identify Change → Assess Data Impact → Update Inventory → Review Security/Privacy Requirements → Update Risk/Controls → Approve Where Required → Retain Evidence


24. Data Discovery and Reconciliation

The organization should periodically compare the Data Inventory against actual systems.

For example:

Data Inventory

Customer data → AWS RDS

Actual Environment

AWS RDS
S3
Customer Support SaaS
Analytics Platform
Backup Environment

If the organization discovers customer data being stored in an additional system, the inventory should be updated and the new processing/storage location assessed.


25. Shadow Data

The organization should consider the possibility of data being stored outside approved systems.

Examples:

  • Employee using personal cloud storage
  • Customer data copied into spreadsheets
  • Production data copied to development
  • Customer information stored in an unauthorized AI tool
  • Sensitive information shared through personal messaging applications

A practical process is:

Detect → Identify Data → Assess Risk → Restrict/Approve → Move/Delete → Update Inventory → Monitor


26. Data in Development and Test Environments

Production data should not automatically be copied into development or testing environments.

Before using production data in non-production environments, consider:

  • Business justification
  • Data classification
  • Privacy requirements
  • Access restrictions
  • Masking/anonymization
  • Security controls
  • Retention
  • Deletion

Where possible, use synthetic or appropriately anonymized test data.


27. Backup Data

Backups should also be considered in the Data Inventory where relevant.

Document:

  • What data is backed up
  • Backup location
  • Backup owner
  • Retention period
  • Encryption
  • Access restrictions
  • Recovery requirements
  • Supplier/cloud provider
  • Secure deletion requirements

Deleting data from a production database does not necessarily mean that all backup copies have immediately disappeared.


28. Data Inventory Roles

Data Owner

  • Defines business purpose.
  • Confirms data classification.
  • Supports access decisions.
  • Supports retention requirements.
  • Reviews the data record.

System/Application Owner

  • Identifies where data is processed.
  • Ensures appropriate technical controls.
  • Supports system changes.

Security/ISMS Manager

  • Ensures security requirements are considered.
  • Links data to risk management.
  • Supports reviews and audits.

Privacy/Legal

Where applicable:

  • Determines privacy/legal requirements.
  • Reviews processing activities.
  • Supports data transfer and retention requirements.
  • Advises on regulatory obligations.

IT/Cloud/Engineering

  • Maintains technical information.
  • Implements security controls.
  • Supports data discovery and deletion.

Employees

  • Handle organizational data according to security and privacy requirements.
  • Report unauthorized data storage or sharing.

29. Audit Evidence

An auditor may select a data set and trace:

Data → Owner → Classification → System → Storage → Access → Security Controls → Risk → Retention → Disposal

Possible evidence includes:

  • Data Inventory
  • Asset Inventory
  • Data Flow Diagram
  • Access reviews
  • Risk Register
  • Security configurations
  • Encryption configuration
  • Backup records
  • Supplier assessments
  • Contracts
  • Retention schedules
  • Deletion records
  • Privacy assessments
  • Incident records
  • Internal audit records

30. Common Mistakes

Mistake 1 — Creating a list of data without locations

Knowing that “customer data” exists is not enough. The organization should understand where it is stored and processed.

Mistake 2 — Ignoring third-party systems

Customer or employee data may exist in SaaS platforms, cloud services, support systems, and external processors.

Mistake 3 — Treating the inventory as a one-time exercise

Data environments change continuously.

Mistake 4 — Not identifying owners

Important data should have accountable ownership.

Mistake 5 — Ignoring backups

Data may continue to exist in backup systems after deletion from primary systems.

Mistake 6 — Mixing production and test data

Production data in development environments can introduce significant security and privacy risks.

Mistake 7 — Assuming all data requires the same protection

Protection should be proportionate to classification, risk, business value, and applicable requirements.

Mistake 8 — Confusing Data Inventory with RoPA

A data inventory supports privacy management but may not contain all information required for a formal RoPA.


31. Startup-Friendly Minimum Data Inventory

A startup can begin with a simple spreadsheet containing:

Data IDDataOwnerSystemLocationClassificationPersonal DataUsersThird PartyRetentionRiskStatus
DATA-001Customer Account DataOperationsSaaS AppAWS RDSConfidentialYesSupport/EngineeringAWSDefinedR-001Active
DATA-002Employee RecordsHRHR SaaSSaaS ProviderConfidentialYesHRHR ProviderDefinedR-002Active
DATA-003Source CodeEngineeringGitHubCloudConfidentialNoEngineeringGitHubBusiness requirementR-003Active
DATA-004Security LogsSecuritySIEMCloudConfidentialPossibleSecuritySIEM ProviderDefinedR-004Active

The inventory can later be integrated into a GRC, privacy management, CMDB, or data discovery platform as the organization grows.


32. Quick Data Inventory Checklist

CheckYes/NoEvidence
Is important organizational data identified?
Is the data owner assigned?
Is the source of data documented?
Is the processing purpose documented?
Is the data classification defined?
Is the system/application identified?
Is the storage location known?
Are data flows understood where necessary?
Are authorized users identified?
Are third-party processors identified?
Are external sharing arrangements documented?
Is data location known?
Are security controls identified?
Is encryption addressed where appropriate?
Are backup requirements understood?
Is retention defined?
Is secure disposal defined?
Are related risks identified?
Are applicable legal/regulatory requirements identified?
Is the inventory periodically reviewed?
Is the inventory updated after significant changes?

33. Relationship with Other ISMS Documents

The Data Inventory should connect with:

Information & Asset Inventory
→ What assets process or store the data?

Asset Ownership Register
→ Who owns the asset?

Asset Classification Procedure
→ How is the information classified?

Risk Assessment
→ What could happen to the data?

Risk Treatment Plan
→ What protection is required?

Access Control Policy
→ Who can access the data?

SaaS Application Register
→ Which third-party applications process the data?

Supplier Security Assessment
→ How are external processors assessed?

Data Retention/Deletion Procedure
→ How long is data retained and how is it deleted?

Incident/Breach Response
→ What happens if the data is compromised?

Privacy/RoPA Records
→ What additional privacy information is required?

The overall relationship is:

Data → Owner → Classification → Location → Processing → Access → Sharing → Risk → Controls → Retention → Disposal → Evidence


34. Final Principle

A useful Data Inventory should allow the organization to answer five basic questions:

What data do we have?
Where is it?
Who uses it?
How is it protected?
When and how is it removed?

The practical lifecycle is:

Discover → Identify → Classify → Map → Assess → Protect → Monitor → Retain → Review → Delete → Verify → Improve

The objective is not to create an unnecessarily large spreadsheet. The objective is to maintain enough visibility to understand the organization’s important information, its movement through systems and suppliers, its security risks, and the controls required to protect it.

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