What evidence do auditors commonly ask for on COS-02 Security requirements for connections in the Cloud Service Provider's network?

Published connection requirement document listing permitted protocols for each zone; Communication matrix defining allowed source and destination pairings; Design showing administration and monitoring traffic carried on distinct paths; Provisions governing site-to-site and cross-network communication.

What is the most common gap auditors find on COS-02?

Requirements describe zones in general terms without naming the protocols allowed in them

BSI C5 (121-criteria catalogue) · C5: Communication Security

`COS-02` Security requirements for connections in the Cloud Service Provider's network

Design, publish and issue binding connection requirements stating when security zones separate and customers are segregated, which protocols and communication relationships are permitted, how administration and monitoring traffic is kept apart, and which cross-site and cross-network traffic is allowed.

Source: BSI C5 (121-criteria catalogue), COS-02. 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 BSI C5 (121-criteria catalogue) in the compliance library.

The edition of the catalogue is not stamped here; check the edition your attestation is issued against.

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

none for this control

governing documentDocuments that govern the control

Published connection requirement document listing permitted protocols for each zone · Policy repository / GRC workspace
Communication matrix defining allowed source and destination pairings · Policy repository / GRC workspace
Design showing administration and monitoring traffic carried on distinct paths · Policy repository / GRC workspace
Provisions governing site-to-site and cross-network communication · 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

Requirements describe zones in general terms without naming the protocols allowed in them
Administrative traffic carried on the same segment as production payload flows
Interconnections built by engineering teams with no reference back to the stated requirements

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

COS-01 Technical safeguards · COS-03 Monitoring of connections in the Cloud Service Provider's network