Exam CISSP topic 1 question 130 discussion

3-4 feet deters casual trespassers. 6-7 feet too high to climb — may block vision. 8 feet with 3 strands of barbed wire will deter determined intruders and is generally considered as the standard height and configuration.

I know A seems the obvious answer as per OSG, but the keyword is "cost-effective" A. Fences three to four feet high with a turnstile - did you consider the cost of the turnstile? B. Fences six to seven feet high with a painted gate - did you consider the cost of a painted gate? C. Fences accompanied by patrolling security guards - an easy one, they are expensive! D. Fences eight or more feet high with three strands of barbed wire - this solves the purpose and won't cost compared to A & B

LOL I can't believe nobody selected B. A. lowest price for fences, however, 4 feet high fence might not much an effective deterrent, for residential yes could be acceptable, but not offices and buildings — also I have not seen a perimeter fence with a turnstile? how would cars enter? turnstile is good control for piggy-backing on building entrances, not perimeter defenses. Bollards might be a better choice than turnstile but also costly. C. Good deterrent, but additional cost for a security guard. D. Best deterrent but has the highest cost, may not be cost effective.

This would also depend on linear size of the gate. A massive campus with that is 10000 acres with barbed wire and a taller fence would cost significantly more than one turnstile and a gate half the size. A causal trespasser who sees any fence, by definition would be deterred by an obstacle.

Answer A) Question stated "casual trespassers".

For a causal trespasser, 3-4 feet should be enough. Source: https://resources.infosecinstitute.com/certifications/cissp/cissp-perimeter-defenses/ Different heights provide varying degrees of protection 3-4 feet deters casual trespassers. 6-7 feet too high to climb — may block vision. 8 feet with 3 strands of barbed wire will deter determined intruders and is generally considered as the standard height and configuration.

the examiner is asking for option D, and we will provide hom with the option. However i do not agree in full, consider this, trees can be climbed, all you need is a rope and you are in the premises, all i am saying is that this may not be the best solution even with eight feel high, something to think about

"MUST COST-EFFICIENTLY DETER CASUAL TRESPASSERS" https://resources.infosecinstitute.com/certification/cissp-perimeter-defenses/#:~:text=Different%20heights%20provide,deters%20casual%20trespassers.

Unless your trespasser is a midget a 3-4 foot fence wouldn't deter anyone. I'd go with D

Turnstile is not cost effective and should be installed in the building.

Fences 2-to-3 feet high can be easily crossed and would not be considered a deterrent. 3-to-4 foot fence will deter only casual. 5-to-7 feet high are considered more difficult to climb than a shorter fence. 8 feet high should be used to deter a determined intruder.

Agreed, A is the answer

it's A

...casual deterrent..

OSG Various types of fences are effective against different types of intruders: ✓ ■ Fences 3 to 4 feet high deter casual trespassers. ✓ ■ Fences 6 to 7 feet high are too hard to climb easily and deter most intruders, except determined ones. ✓ ■ Fences 8 or more feet high with strands of barbed or razor wire deter even determined intruders.

security guards, it is not cost-efficintly , the answer should be D