EvidenceSheet
NIST SP 800-171 Rev 3 · 03.16 SA (System and Services Acquisition)

03.16.03 External System Services

Require providers of external system services to comply with security requirements; define and document oversight and user roles; monitor compliance of external service providers.

Source: NIST SP 800-171 Rev 3, 03.16.03. 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 NIST SP 800-171 Rev 3 in the compliance library.

3
artefacts
1
held by a system
1
at each review
moderate
to go live
SIEM / log platform
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

  • Vendor monitoring records · SIEM / log platform

periodic reviewEvidence produced at each review

  • SOC 2 reports · Document repository

governing documentDocuments that govern the control

  • Vendor security requirements clauses · Vendor register / contract repository

First move

Start with the 1 of 3 artefacts that already live in a system (SIEM / log platform); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

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.

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03.16.02 Unsupported System Components · 03.17.01 Supply Chain Risk Management Plan