From my book, Antiterrorism and Threat Response, Planning and Implementation, there are five fundamentals to antiterrorism planning:
1 Threat vulnerability assessment. This is a realistic assessment based on the actual threat to your organization or installation, and your organization’s ability to defend against that threat.
2 Security measures. This is a mixture of procedural and physical barriers designed to reduce the vulnerability of the organization or installation to an attack identified in the threat assessment phase—in other words, fences, alarms, locks, guards, access control, etc. These measures will increase or decrease with the prevailing terrorism threat.
3 Observation plan. Your personnel should be trained to recognize the threat when they see it. Most terrorist attacks are preceded by an extensive period of surveillance, and this surveillance can be detected by trained observers. This information is used to modify security measures and alert counterterrorism forces.
4 Random antiterrorism measures. A terrorist organization conducting surveillance against your organization or installation will try to develop a picture of your security plans and procedures. It will seek to learn your layout and routine. In antiterrorism planning, routine is weakness. Random antiterrorism measures deter attack by sowing doubt in the minds of the attackers. By constantly changing details of your defensive posture, terrorists will not be able to form a clear picture of the target’s defences, and therefore cannot ensure a high probability of success. This in itself is often enough reason for a terrorist group to move on to another, less prepared target.
5 Response planning. What will you do if surveillance is detected? What will you do if your organization is attacked? Response planning is crisis response planning. If your personnel are well-trained and rehearsed, the effects of a terrorist attack can often be swiftly contained.
Design Basis Threat / Vulnerability of Integrated Security Analysis
The first two activities in antiterrorism planning, the TVA and security measures, are best conducted through the use of a design basis threat (DBT) and the Vulnerability of Integrated Security Analysis (VISA) process. The DBT describes the capabilities and resources available to potential insider and outsider adversaries, and is used to develop the physical protection system (PPS). To a large extent, your DBT is the threat assessment.
The VISA process uses the DBT to create reasonable and credible scenarios that achieve one or more of the unacceptable consequences of an attack while staying within the resources and capabilities described in the DBT. VISA is the vulnerability assessment and security measures part of antiterrorism planning.
For more information on the DBT/VISA process, please go to this page in my website.