What evidence do auditors commonly ask for on SC-40(4) Wireless Link Protection | Signal Parameter Identification?

System and communications protection policy; Access control policy and procedures; Procedures addressing system design documentation; Wireless network diagrams; System configuration settings and associated documentation; System architecture.

What is the most common gap auditors find on SC-40(4)?

Defined wireless transmitters can be identified by their signal parameters

NIST SP 800-53 Rev 5 · SC - System and Communications Protection

`SC-40(4)` Wireless Link Protection | Signal Parameter Identification

Implement cryptographic mechanisms to prevent the identification of organization-defined wireless transmitters by using the transmitter signal parameters.

Source: NIST SP 800-53 Rev 5, SC-40(4). 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

none for this control

periodic reviewEvidence produced at each review

System audit records · Policy repository / GRC workspace
Test of Cryptographic mechanisms preventing the identification of wireless transmitters · Document repository

governing documentDocuments that govern the control

System and communications protection policy · Policy repository / GRC workspace
Access control policy and procedures · Policy repository / GRC workspace
Procedures addressing system design documentation · Policy repository / GRC workspace
Wireless network diagrams · Policy repository / GRC workspace
System configuration settings and associated documentation · Policy repository / GRC workspace
System architecture · Policy repository / GRC workspace
System communications hardware and software · Document repository
System security plan · Policy repository / GRC workspace

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

Defined wireless transmitters can be identified by their signal parameters
The transmitters requiring protection against identification were never defined

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

SC-40(3) Wireless Link Protection | Imitative or Manipulative Communications Deception · SC-41 Port and I/O Device Access