Wireless Security.pdf - PDF Archive

Managing Access 297
of the session and those of the files accessed during the session are used, in
turn, to label output from the session. This ensures that information is uniformly
protected throughout its life on the system.
Security labels are a very strong form of access control. Because they are costly and
difficult to administer, security labels are best suited for information systems that
have very strict security requirements (such as that used by government, financial, and
research and development [R & D] organizations that handle classified information or
information whose loss would severely or critically degrade the financial viability of the
organization). Security labels are an excellent means of consistent enforcement of access
restrictions; however, their administration and highly inflexible characteristics can be a
significant deterrent to their use.
Security labels cannot generally be changed because they are permanently linked to
specific information. For this reason, user-accessible data cannot be disclosed as a result
of a user copying information and changing the access rights on a file in an attempt to
make that information more accessible than the document owner originally intended.
This feature eliminates most types of human errors and malicious software problems
that compromise data. The drawback to using security labels is that sometimes the very
feature that protects user data also prevents legitimate use of some information. As an
example, it is impossible to cut and paste information from documents with different
access levels assigned to their respective labels.
13.1.5.2 Data Categorization
One method used to ease the burden necessary for administration of security labeling
is categorizing data by similar protection requirements (data categorization). As an
example, a label could be developed specifically for “ Company Proprietary Data. ” This
label would mark information that can be disclosed only to the organization’s employees.
Another label, “ General Release Data, ” could be used to mark information that is
available to anyone.
When considering the implementation of mandatory access controls with security labels,
one must decide between using a rule-based approach, where access is granted based on
resource rules, or using an administratively directed approach, where access is granted
by an administrator who oversees the resources. Using a rule-based approach is most
often preferred because members of a group can be granted access simply by validating
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