Fundamentals of Information Systems Security, 4th Edition

How to Verify Security Controls

One specific class of monitoring controls can provide a very good layer of security. This class of controls monitors network and system activity to detect unusual or suspicious behavior, and some controls in this class can even respond to detected suspicious activity and possibly stop an attack in progress. Controls that monitor activity include IDSs, IPSs, and firewalls.

NOTE

There are two important types of primary security controls: preventive and detective. A detective control (i.e., IDS) simply detects when a defined event occurs, whereas a preventive control (i.e., IPS) prevents the event from ever happening. ...