ISO 27001 A.8.11: data masking, explained for startups

A.8.11 Data masking

Sensitive data is hidden or masked where people do not need to see it. What proves it: where sensitive data is masked or hidden, and how.

A certification auditor samples masking configuration. A file that usually does the job: masking rules in your database or application, or a sample record showing masked fields.

How to put it in place

Each step leaves a record, and the record is what the auditor samples rather than the step itself. Inside Polara, the control card for A.8.11 walks you through it in this order.

1. List where sensitive fields appear: support tools, logs, analytics and test data.
2. Mask or remove them where they are not needed.
3. Check a sample after each change.

The free ISO 27001 readiness assessment asks one question that evidences it:

• What data do your test environments use?

Policies, connectors and the SOC 2 overlap

In the ISO 27001 policy pack, the Operations Security Policy covers A.8.11. An auditor reads the policy for the rule, then samples the records to see the rule was followed.

The same evidence counts toward SOC 2. The Trust Services criteria that cover this ground: CC6.1, logical access and C1.1, confidential data handling.

Technological controls

A.8.11 is one of the 34 technological controls in Annex A. The controls built into your systems: access, devices, malware, vulnerabilities, backups, logging, networks, encryption and secure development. Exports and settings screenshots prove most of them.

Nearby controls in the same theme:

• A.8.8, vulnerability management
• A.8.9, configuration management
• A.8.10, deleting information
• A.8.12, data leak prevention
• A.8.13, backups
• A.8.14, redundancy

Before it: A.8.10, deleting information. After it: A.8.12, data leak prevention. Every control, by theme, is on the Annex A controls page.