Quick Answer
The answer is a mantrap door. This is a preventive physical security control because it actively blocks unauthorized entry through a series of interlocking doors that require authentication and verification before granting passage, physically stopping a breach before it occurs rather than merely detecting or monitoring it. On the CISSP exam, this concept tests your ability to distinguish preventive controls from detective or deterrent measures; a common trap is confusing a mantrap with a simple access log or CCTV, which only record events. Remember that preventive controls stop the action, while detective controls catch it after the fact. A useful memory tip is to think of a mantrap as a "physical gatekeeper" that says "prove yourself first" rather than "we'll catch you later."
This CISSP practice question tests your understanding of security architecture and engineering. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
In the context of physical security, which of the following is an example of a preventive control?
Security guards monitoring
Why wrong: Incorrect. Guards can be deterrent or detective.
CCTV cameras
Why wrong: Incorrect. CCTV is a detective control.
Intrusion detection system
Why wrong: Incorrect. IDS is detective.
Mantrap door
Correct. A mantrap prevents tailgating and unauthorized access.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Mantrap door
A mantrap door is a preventive physical security control because it actively prevents unauthorized entry by requiring authentication and verification before allowing passage through a series of interlocking doors. Unlike monitoring or detection systems, a mantrap physically blocks access until the user is validated, thereby stopping a breach before it occurs.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Security guards monitoring
Why it's wrong here
Incorrect. Guards can be deterrent or detective.
CCTV cameras
Why it's wrong here
Incorrect. CCTV is a detective control.
Intrusion detection system
Why it's wrong here
Incorrect. IDS is detective.
Mantrap door
Why this is correct
Correct. A mantrap prevents tailgating and unauthorized access.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is confusing preventive controls (which stop an incident) with detective controls (which identify an incident after it occurs), leading candidates to incorrectly select CCTV or IDS as preventive measures.
Detailed technical explanation
A mantrap typically uses two or more interlocking doors with electronic locks controlled by an access control system (e.g., card readers, biometrics). The system enforces a 'one-person-per-authentication' rule, preventing tailgating by weighing or counting occupants in the vestibule. In high-security environments, mantrap doors are often integrated with metal detectors or explosive trace detection to further prevent weapon or contraband entry.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Security Architecture and Engineering — This question tests Security Architecture and Engineering — Read the scenario before looking for a memorised answer..
The correct answer is: Mantrap door — A mantrap door is a preventive physical security control because it actively prevents unauthorized entry by requiring authentication and verification before allowing passage through a series of interlocking doors. Unlike monitoring or detection systems, a mantrap physically blocks access until the user is validated, thereby stopping a breach before it occurs.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO of the following are examples of physical security controls?
easyWhy B: Biometric door locks are physical security controls because they restrict physical access to a facility or room by verifying a unique biological trait (e.g., fingerprint, iris pattern). This falls under the domain of physical access control, which is a core component of physical security, not logical or administrative controls.
Last reviewed: Jun 24, 2026
This CISSP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISSP exam.
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