The multilevel security mode permits two or more classification levels of information to be processed at the same time when all the users do not have the clearance of formal approval to access all the information being processed by the system.
In dedicated security mode, all users have the clearance or authorization and need-to-know to all data processed within the system.
In system-high security mode, all users have a security clearance or authorization to access the information but not necessarily a need-to-know for all the information processed on the system (only some of the data).
In compartmented security mode, all users have the clearance to access all the information processed by the system, but might not have the need-to-know and formal access approval.
Generally, Security modes refer to information systems security modes of operations used in mandatory access control (MAC) systems. Often, these systems contain information at various levels of security classification.
The mode of operation is determined by:
The type of users who will be directly or indirectly accessing the system.
The type of data, including classification levels, compartments, and categories, that are processed on the system.
The type of levels of users, their need to know, and formal access approvals that the users will have.
Dedicated security mode In this mode of operation, all users must have:
Signed NDA for ALL information on the system.
Proper clearance for ALL information on the system.
Formal access approval for ALL information on the system.
A valid need to know for ALL information on the system.
All users can access ALL data. System high security mode
In this mode of operation, all users must have:
Signed NDA for ALL information on the system. Proper clearance for ALL information on the system. Formal access approval for ALL information on the system. A valid need to know for SOME information on the system.
All users can access SOME data, based on their need to know.
Compartmented security mode In this mode of operation, all users must have:
Signed NDA for ALL information on the system. Proper clearance for ALL information on the system. Formal access approval for SOME information they will access on the system. A valid need to know for SOME information on the system.
All users can access SOME data, based on their need to know and formal access approval.
Multilevel security mode In this mode of operation, all users must have:
Signed NDA for ALL information on the system. Proper clearance for SOME information on the system. Formal access approval for SOME information on the system. A valid need to know for SOME information on the system.
All users can access SOME data, based on their need to know, clearance and formal access approval.
REFERENCES:
WALLHOFF, John, CBK#6 Security Architecture and Models (CISSP Study Guide), April 2002 (page 6). and http://en.wikipedia.org/wiki/Security_Modes