What evidence do auditors commonly ask for on SC.L2-3.13.15 Communications Authenticity?

Session authenticity mechanism configuration, for example session tokens and mutual authentication; Evidence sessions are bound and validated; Configuration preventing session fixation and reuse.

What is the most common gap auditors find on SC.L2-3.13.15?

Confidentiality protected while session authenticity is not

CMMC 2.0 · System and Communications Protection

`SC.L2-3.13.15` Communications Authenticity

Protect the authenticity of communications sessions so a session cannot be hijacked or spoofed.

Source: CMMC 2.0, SC.L2-3.13.15. 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 CMMC 2.0 in the compliance library.

artefacts

held by a system

at each review

easy

to go live

Identity provider / directory

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

Session authenticity mechanism configuration, for example session tokens and mutual authentication · Identity provider / directory
Configuration preventing session fixation and reuse · Cloud console / configuration management

periodic reviewEvidence produced at each review

Evidence sessions are bound and validated · Document repository

governing documentDocuments that govern the control

none for this control

First move

Automate the pull from your Identity provider / directory. Scheduled export of users, roles and MFA state from the directory; access-review completion pulled from the IdP, not a spreadsheet.

Common gaps auditors find

Confidentiality protected while session authenticity is not
Session identifiers predictable or not regenerated after authentication
Application sessions outside the assessed scope

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.L2-3.13.14 Voice over Internet Protocol · SC.L2-3.13.16 Data at Rest