What evidence do auditors commonly ask for on A.2.5.8 Engagement of a subcontractor to process PII?

Written customer authorization for each subcontractor, whether general or specific; Written contract with every subcontractor carrying the processor control obligations; Justification for any processor control not required of a subcontractor; Evidence the risk assessment and processing scope informed which controls were required; Reconciliation between subcontractors actually used and those authorized.

What is the most common gap auditors find on A.2.5.8?

Subcontractor engaged on the strength of a general authorization that does not in fact cover it

ISO/IEC 27701:2025 · Annex A Table A.2 PIMS controls for PII processors

`A.2.5.8` Engagement of a subcontractor to process PII

The organization must bring in a subcontractor to process personal data only as the customer contract allows, and must have the customer's written authorization before the subcontractor starts, given either through suitable terms in the customer contract or by a one-off agreement. It must hold a written contract with each such subcontractor that deals with putting the relevant processor controls in place, requiring the subcontractor to implement them with regard to the risk assessment and the extent of the processing. All of those controls are to be treated as relevant unless an exclusion is justified; responsibilities may be divided in other ways, provided each control has been considered and the outcome documented.

Source: ISO/IEC 27701:2025, A.2.5.8. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open ISO/IEC 27701:2025 in the compliance library.

artefacts

held by a system

at each review

hard

to go live

Document repository

where the evidence lives

teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

none for this control

periodic reviewEvidence produced at each review

Evidence the risk assessment and processing scope informed which controls were required · Policy repository / GRC workspace

governing documentDocuments that govern the control

Written customer authorization for each subcontractor, whether general or specific · Document repository
Written contract with every subcontractor carrying the processor control obligations · Vendor register / contract repository
Justification for any processor control not required of a subcontractor · Document repository
Reconciliation between subcontractors actually used and those authorized · Document repository

First move

No system holds this evidence for you: it is people and documents. Reminders and routing to the owner still save time. Put the document under version control with an owner and review date, and log each review as a record with reviewer and date.

Common gaps auditors find

Subcontractor engaged on the strength of a general authorization that does not in fact cover it
Subcontractor contracts carrying security terms while the processor control set is never flowed down
Controls omitted by silence rather than justified exclusion
Tooling and infrastructure providers that process personal data not recognised as subcontractors
Authorization obtained once and not revisited when the subcontractor's scope of processing grew

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

Build my evidence sheet

A.2.5.7 Disclosure of subcontractors used to process PII · A.2.5.9 Change of subcontractor to process PII