PD-0137: CC V3 PP Conformance Type Consistency

This decision represents a long-term technical decision based on an OD, and may not be the same as the final results of the source OD. With respect to published criteria documentation and scheme documents, it provides suggested guidance on evaluation direction, but is not authoritative. Authoritative decisions are provided through the published criteria documents and published scheme and international interpretations thereof. With respect to published PPs, PDs are authoritative corrections to the PP, based on input from the PP author (if available), that are in force until the publication of the next revision of that PP.

Issue

In CCv3.1, ASE_CCL.1-10 requires, in paragraph 361 and 362, that, for a claim of "demonstrable" PP compliance, CC Part 1 Annex D (in particular, Annex D.3) is to be used. This annex defines, in paragraph 444 first bullet, that, when an ST is more restrictive than a PP, then "all TOEs that meet the PP also meet the ST". This statement is inconsistent because when an ST is more restrictive, i.e. has stricter assumptions, threats, etc. a TOE that conforms with the PP is not necessarily compliant with the ST.

Similarly, in CC Part 1 paragraph 445, first bullet, the second sub-bullet contains a requirement that is also inconsistent; and again in paragraph 445, second bullet, second sub-bullet.

Resolution

1. In CC Part 1, paragraph 444: rephrase first bullet to "all TOEs that meet the ST also meet the PP, and".

2. In CC Part 1, paragraph 445: rephrase first bullet, second sub-bullet to "all operational environments that would meet the security problem definition in the ST would also meet the security problem definition in the PP."

3. In CC Part 1, paragraph 445: rephrase second bullet, second sub-bullet to "all operational environments that would meet the security objectives for the operational environment in the ST would also meet the security objectives for the operational environment in the PP."

Support

It would seem that the CC V3 authors wrote paragraph 444 and 445 a little too quickly. In item 1 of the resolution, an alternate wording would be something to the effect that any TOE must conform to BOTH the ST and the PP. Regardless, the Issue statement is clear. It is easy to imagine TOEs conforming to a PP that do not conform to an ST that is more restrictive. Likewise in items 2 and 3, it is easy to imagine operational environments that would conform to a PP yet not conform to a more restrictive ST.

Modification History:

2007-05-31

PD Created. [ODRB May 2007 Agenda Item 3.a.iii]

References:

• None

Related NIs:

• None

Related CCIMB-INTERPs:

• None

Source OD: 0263