Page 563 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

latter.

Compartmented mode Compartmented mode systems weaken
these requirements one step further:

Each user must have a valid security clearance that permits access
to all information processed by the system.

Each user must have access approval for any information they will
have access to on the system.

Each user must have a valid need to know for all information they
will have access to on the system.

Notice that the major difference between compartmented mode

systems and system high mode systems is that users of a
compartmented mode system do not necessarily have access approval
for all the information on the system. However, as with system high
and dedicated systems, all users of the system must still have
appropriate security clearances. In a special implementation of this
mode called compartmented mode workstations (CMWs), users with
the necessary clearances can process multiple compartments of data at

the same time.

CMWs require that two forms of security labels be placed on objects:
sensitivity levels and information labels. Sensitivity levels describe the
levels at which objects must be protected. These are common among
all four of the modes. Information labels prevent data
overclassification and associate additional information with the
objects, which assists in proper and accurate data labeling not related

to access control.

Multilevel Mode The government’s definition of multilevel mode
systems pretty much parallels the technical definition given in the
previous section. However, for consistency, we’ll express it in terms of
clearance, access approval, and need to know:

Some users do not have a valid security clearance for all

information processed by the system. Thus, access is controlled by
whether the subject’s clearance level dominates the object’s
sensitivity label.