Page 155 - CISSO_Prep_ Guide

authentication - through an ID card or biometrics before
allowing a subject (the person) to gain access. The security
guard may also log all activity - who enters and leaves, who
signed in a visitor, who tried to enter but was refused - all of
these can be logged and used for future investigation, if
necessary. It is important to remember that the security guard
only enforces the rules given by the owner. The security guard is
NOT responsible for determining who should and who should
not have access - only the owner can decide who should be let
in, and what procedures must be followed to enable that access.
Several simple and logical rules must apply to the reference
monitor. The rules are:
1. The access control system must mediate ALL access
- in other words, whenever an entity desires to
access. It must intercept the access request, verify
whether that access should be permitted and then
grant (or deny) access according to the rules
provided by the owner.
2. The access control system must be testable; there
must be a way to validate that the access controls are
working correctly and only allowing appropriate
access to authorized personnel.
3. The access control system must be protected from
modification or tampering - no one should be able to
change the access control rules except through an
authorized process. The entity requesting access (the
subject) should not be able to change its own rules).