Clarification on SSM-1 DN-1 → DN-2 Flow (YES/NO Interpretation)

[Roger2625]

Asset under assessment:
Network asset– LAN Configuration (Network asset, Sensitive network function configuration)

Current scenario:

• LAN configuration is persistently stored on the device

• It is only accessible and modifiable by the root user

• Unprivileged users cannot read or modify the configuration

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Decision Tree Questions (SSM-1)

DT.SSM-1.DN-1 asks:

Is the storage of the network asset protected by physical or logical measures in the equipment’s target operational environment?

In this scenario, logical protection exists via privilege separation (root-only access).

Question 1:
➡️Network asset Should DT.SSM-1.DN-1 therefore be evaluated as YES?

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DT.SSM-1.DN-2 asks:

Is the storage of the network asset implemented by a secure storage mechanism?

Given that LAN configuration is Sensitive (not Confidential) and integrity is protected by access control:

Question 2:
➡️ If DN-1 = YES, should the assessment proceed to DT.SSM-1.DN-2, and can DN-2 be evaluated as YES, resulting in SSM-1 = PASS?

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YES / NO confusion clarification

In DT.SSM , the visual layout appears to suggest that a YES outcome at DN-1 leads directly to Not Applicable, while NO proceeds to DN-2. However, semantically:

• A NO at DN-1 (no protection at all) would make SSM-1 Not Applicable

• A YES at DN-1 logically requires further evaluation at DN-2

Question 3:
➡️ Can you confirm that DN-1 = YES → DN-2, and DN-1 = NO → Not Applicable, and that the diagram should be interpreted semantically rather than by arrow placement?

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My question is ??
For a LAN configuration stored persistently and accessible only to root, does DN-1 evaluate to YES (thus proceeding to DN-2), or should this be considered Not Applicable under SSM-1?

[zealience]

Hello @Roger2625 ,

Thank you for your questions. Sorry for the delay.

Question 1:
In your example, there are no physical or logical measures in the equipment’s target operational environment.
The key element here is "in the equipment’s target operational environment". I would only answer DT.SSM-1.DN-1 with Yes when the measures is in the environment in which the equipment is deployed, not in the equipment itself. For example, a logical measure in the equipment’s target operational environment could be a firewall in the network to which the equipment is connected to. A physical measure could be a door with a badge reader that only authorized persons possess, and therefore only them can access the room where the equipment is located.

Question 2:
In the Decision Tree of SSM-1, DN-1 asks whether there are physical or logical measures in the equipment’s target operational environment to protect asset stored. When you answer Yes, it leads to SSM-1 = NOT APPLICABLE, and stops there, i.e., there is no need for secure storage mechanism (since other measures protect the assets stored).
However when there are no physical/logical measures in the operational environment, DN-1 is No and leads to DN-2 which asks whether assets are stored using a secure storage mechanism. If you have in place such a secure mechanism, that leads to SSM-1 = PASS. You will then move on to SSM-2, in which you will document how the secure storage mechanism is implemented. There are 5 possibilities provided by the "Implementation Categories". One of them is Access Control. This is the one to choose in your case.

Question 3:
In my opinion the SSM-1 Decision Tree is ok. One can read it literally:
DN-1: Is the storage of the [...] assets protected by [...] measures in the operational environment?

• Yes? Then there is no need for secure storage mechanism since other measures protect the assets stored, and therefore SSM-1 is NOT APPLICABLE (keep in mind that SSM-1 is meant to identify the applicability of secure storage mechanisms)
• No? Then there is a need to store assets securely since there are no other measures to protect them. Hence we need to go to DN-2, where we need a storage mechanism to pass SSM-1.

I hope this helps.

Guillaume