What evidence do auditors commonly ask for on SA-20 Customized Development of Critical Components?

Supply chain risk management plan; System and services acquisition policy; Procedures addressing the customized development of critical system components; System design documentation; System configuration settings and associated documentation; System development life cycle documentation addressing the custom development of critical system components.

What is the most common gap auditors find on SA-20?

The defined critical components were never reimplemented or custom developed

NIST SP 800-53 Rev 5 · SA - System and Services Acquisition

`SA-20` Customized Development of Critical Components

Reimplement or custom develop the following critical system components: organization-defined critical system components.

Source: NIST SP 800-53 Rev 5, SA-20. 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 800-53 Rev 5 in the compliance library.

Base controls and their enhancements. Which apply follows the baseline you are assessed against (for example FedRAMP Moderate or High, or the low, moderate and high baselines of SP 800-53B). Text in square brackets is a parameter your organisation sets.

artefacts

held by a system

at each review

hard

to go live

Policy repository / GRC workspace

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

Configuration management records · Cloud console / configuration management

periodic reviewEvidence produced at each review

System audit records · Policy repository / GRC workspace
Test of Organizational processes for the reimplementation or customized development of critical system components; mechanisms supporting and/or implementing the reimplementation or customized development of critical system components · Document repository

governing documentDocuments that govern the control

Supply chain risk management plan · Policy repository / GRC workspace
System and services acquisition policy · Policy repository / GRC workspace
Procedures addressing the customized development of critical system components · Policy repository / GRC workspace
System design documentation · Document repository
System configuration settings and associated documentation · Policy repository / GRC workspace
System development life cycle documentation addressing the custom development of critical system components · Document repository
System security plan · Policy repository / GRC workspace

First move

Mostly documents and reviews. Pull the 1 system-held artefact from your Cloud console / configuration management on a schedule; put the documents under version control with an owner and review date, and log each review as a dated record with a named reviewer.

Common gaps auditors find

The defined critical components were never reimplemented or custom developed
The critical components requiring custom development were never identified

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

SA-17(9) Developer Security and Privacy Architecture and Design | Design Diversity · SA-21 Developer Screening