Tuesday, February 12, 2008

SVA Definitions – Vulnerability, Target Attractiveness, Likelihood of Success

Continuing yesterday’s blog (“SVA Definitions – Risk, Consequences and Threat”) we continue to look at some definitions that need to be understood by SVA team members at high-risk chemical facilities. As before the definitions come from the CCPS SVA Guideline Book,  "Guidelines for Analyzing and Managing the Security Vulnerabilities of Fixed Chemical Sites."


Definition of Vulnerability 


In an SVA vulnerability is “any weakness that can be exploited by an adversary to gain unauthorized access to an asset.” Vulnerability could be due to a hole in the security precautions protecting the asset, plant operating procedures that allow access, or even management procedures that make unauthorized access easier to achieve.


There are two general methods for assessing vulnerability in the CCPS approach to conducting an SVA. The asset-based approach looks at the threat and hazards associated with assets at the facility. For example a facility with a 60,000-pound chlorine tank and no other COI would look at how that particular asset could be attacked to achieve a catastrophic release, working from the result back to the probable method of attack.


The scenario-based approach focuses more on the potential attackers. The vulnerability assessment looks at various attack scenarios that could be employed against the facility. Looking at, for example, what damage an armed assault team, a vehicle bomber and a cyber attack could do to determine the vulnerability points of the facility.


Which approach to take depends on a number of factors. A team with a strong understanding of terrorist tactics and capabilities would probably favor the scenario-based approach. A team with more of a process background would probably use the asset-based approach.


Definition of Target Attractiveness


Target Attractiveness is a measure of the value of the facility to an adversary when viewed as a target. In large part this depends on the objective of the adversary planning the attack. Thus an accurate assessment of the Target Attractiveness depends on the intelligence available on adversary. This means that in almost all instances only a broad outline of Target Attractiveness can be obtained.


Target Attractiveness can be best used to determine the necessity of doing an SVA. For the purposes of CFATS DHS has determined the Target Attractiveness of all facilities that have completed the Top Screen. Thus the Tier ranking of the facility can serve as a relative measure of Target Attractiveness.


Definition of Likelihood of Adversary Success


The Likelihood of Adversary Success is a measure of the probable success of a security measure to prevent a catastrophic result from a terrorist attack. Once again a quantitative measure is not likely to be determined from available information. There is simply not enough available data.


Once again the judgement of the SVA team will be used to evaluate the various security measures and their effectiveness at reducing the Likelihood of Adversary Success. This is one of the reasons that it is necessary to have a wide variety of skills on the SVA team. Two skill sets that it is imperative for the team to have to make this particular evaluation are a strong understanding of security procedures and devices as well as knowledge of terrorist tactics and capabilities.

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