Page 689 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

In addition to smart/dumb cards and proximity readers, physical
access can be managed with radio-frequency identification (RFID) or

biometric access control devices. See Chapter 13 for a description of
biometric devices. These and other devices, such as cable locks, can
support the protection and securing of equipment.

Intrusion Detection Systems

Intrusion detection systems (IDSs) are systems—automated or manual
—designed to detect an attempted intrusion, breach, or attack; the use
of an unauthorized entry/point; or the occurrence of some specific

event at an unauthorized or abnormal time. Intrusion detection
systems used to monitor physical activity may include security guards,
automated access controls, and motion detectors as well as other
specialty monitoring techniques. These are discussed in more detail in
the later sections “Motion Detectors” and “Intrusion Alarms.”

Physical intrusion detection systems, also called burglar alarms,
detect unauthorized activities and notify the authorities (internal

security or external law enforcement). The most common type of
system uses a simple circuit (aka dry contact switches) consisting of
foil tape in entrance points to detect when a door or window has been
opened.

An intrusion detection mechanism is useful only if it is connected to an
intrusion alarm. (See “Intrusion Alarms” later in this chapter.) An
intrusion alarm notifies authorities about a breach of physical security.

There are two aspects of any intrusion detection and alarm system that

can cause it to fail: how it gets its power and how it communicates. If
the system loses power, the alarm will not function. Thus, a reliable
detection and alarm system has a battery backup with enough stored
power for 24 hours of operation.

If communication lines are cut, an alarm may not function and
security personnel and emergency services will not be notified. Thus, a
reliable detection and alarm system incorporates a heartbeat sensor

for line supervision. A heartbeat sensor is a mechanism by which the
communication pathway is either constantly or periodically checked
with a test signal. If the receiving station detects a failed heartbeat