ISO 27001 Annex A 8.15: Logging

What Control 8.15 means in practice

Generate, protect and retain useful event records for accountability, investigation and monitoring. Test the control through the organisation's actual scope, decisions, ownership and operating records rather than relying on a policy reference alone.

For logging, proportional design depends on the affected services, information, people and dependencies. The evidence below should be adapted to that real boundary.

Implementation steps

1. Step 1. Define ownership, scope and operating criteria for logging.
2. Step 2. Implement monitoring standard that fits the organization’s risks, services and working practices.
3. Step 3. Integrate the activity with relevant change, exception and review processes.
4. Step 4. Review performance and improve the arrangement when risks, technology or obligations change.

What good implementation looks like

• sample events present, accurate and attributable
• missing log sources identified and restored
• retention and access controls operating as designed

Implementation evidence and effectiveness evidence

How an auditor may test Control 8.15

1. Select a representative in-scope service, asset or process.
2. Confirm the accountable owner and expected operation.
3. Trace a recent example: Authentication, privileged activity and security-control changes are logged.
4. Inspect the operating record and corroborating technical evidence.
5. Compare the design with evidence that the control operated effectively.
6. Follow an exception or adverse result through decision and closure.
7. Review trends, metrics and improvement decisions.

Questions to prepare for

• How is logging implemented in practice?
• Who owns the activity and how are decisions approved?
• Show me a recent example from operation through review.
• How are exceptions, changes or overdue actions handled?

Practical examples

Illustrative decision and evidence record

Reviewer note: Test logging with a recent real example; a current operating record normally reveals more than policy wording alone.

Useful performance and coverage measures

• critical log-source coverage
• ingestion failures
• time to retrieve investigation records

Approach for smaller and mature organizations

Smaller organization

Use a clear owner, a proportionate working record, built-in platform capability and a scheduled review. Sample real activity instead of creating duplicate paperwork for logging.

Mature or complex organization

Define service-level ownership, automated coverage reporting, integrated workflow, risk-based exceptions and independent assurance across business units and technology platforms.

Practical implementation checklist

• □ Define ownership, scope and operating criteria for logging.
• □ Implement monitoring standard that fits the organization’s risks, services and working practices.
• □ Integrate the activity with relevant change, exception and review processes.
• □ Review performance and improve the arrangement when risks, technology or obligations change.
• □ Sample evidence has been checked for operation and effectiveness.
• □ Exceptions have owners, rationale, review dates and closure evidence.

Common implementation mistakes

• documenting logging without consistent operation
• unclear ownership or review frequency
• evidence that does not cover the full ISMS scope
• exceptions accepted without risk-based approval or follow-up

Related controls, clauses and resources