[CISSP-D] Re: Q: Subject/Object sensitive label in Multi-level security

Answer D is correct. You may be misunderstanding the concepts here.

1) The question refers to a confidentiality MAC policy. This policy 
(as implemented in BLP) states "no read down" - i.e., a top secret 
user cannot read a secret file. and "no write up" a secret user 
process may not write to a top secret file.

2) Domination. The short hand way of talking about these security 
policies are "no read up" and "no write down" but to be more 
specific you must understand the concept of domination. It basically 
means that the for label A to dominate label B, label A must have a 
equal to or greater than security level than label B (e.g., "Top 
Secret" vs. "Secret") and must have all the categories of B 
(e.g. "Top Secret - AZUL" vs. "Secret - AZUL"). (see any CISSP book 
for an explanation).

3) Answer A can be interpretted to mean "Write Down"
   Answer B is nonsense and uses nonstandard terms
   Answer C is nonsense and uses nonstandard terms 
   Answer D can be interpretted to mean "Write Up"

"Write Down" is prohibited whereas "Write Up" is allowed therefore 
answer D and not A is correct.







--- In CISSP-Discuss@yahoogroups.com, Weifeng Bao <go2sailing@y...> 
wrote:
> Here is the question from cccure.org quiz:
>
> Q: what is necessary for a subject to have write
> access to an object in a Multi-level security policy?
>
> A. The subject's sensitivity label must dominate the
> object's sensitivity label.
> B. The subject's sensitivity label subordinates the
> object's sensitivity label.
> C. The subject's sensitivity label is subordinated by
> the object's senstivity label.
> D. The subject's sensitivity label is dominated by the
> object's sensitivity label.
>
> The given answer D.  However, I think the answer
> should be A.  Do I misunderstand the keywords or
> concept here?
>
> Thanks.
>
> --Weifeng 
>
>
>
>               
> __________________________________ 
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