# SSO-03 Data Processing of Service Organisations

- Domain: SSO – Control and Monitoring of Service Providers and Suppliers
- Since C5:2020: new in C5:2026
- Web page: https://c5.patrickscheid.de/en/sso-03/

## Basic criterion

### SSO-03.01B

If the cloud service provider relies on assets from a supplier or on services from subservice organisations for the operation of the cloud service, it does not allow those suppliers or service organisations to access any cloud service customer data, cloud service derived data or account data. Exceptions are made only if the cloud service provider has performed a risk assessment according to OIS-07 on the possibility of cloud service customer data, cloud service derived data or account data being exposed.

### SSO-03.02B

The cloud service provider obtains written authorisation of the customer prior to the processing of cloud service customer data, cloud service derived data or account data when engaging service organisations. This can be achieved by authorisation of the customer, per service organisation, or by way of a general pre-authorisation between the cloud service provider and the customer.

**Supplementary information:**

This subcriterion does not apply to cloud service derived data that does not contain any customer-owned data. Examples for such cloud service derived data include operational metrics or technical telemetry data.

## Additional criterion

### SSO-03.01AS (additional, sharpens 01B)

If the cloud service provider relies on assets from a supplier or on services from subservice organisations for the operation of the cloud service, it does not allow those suppliers or service organisations to access any cloud service customer data, cloud service derived data or account data. Exceptions are made only if the cloud service provider has performed a risk assessment according to OIS-07 on the possibility of cloud service customer data, cloud service derived data or account data being exposed, and it is ensured that all operations requiring access to those data types are performed or supervised by authorised personnel (cf. HR-01).

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Source: BSI C5:2026, machine-readable edition v1.0.1, © Federal Office for Information Security (BSI) 2026, reproduced unchanged under CC BY-ND 4.0 (https://creativecommons.org/licenses/by-nd/4.0/). Change notes: BSI C5:2026 Changelog, © BSI 2026, CC BY-ND 4.0. Unofficial presentation, not affiliated with BSI.