easyMultiple Choice
Examples of Preventive Physical Security Controls
In the context of physical security, which of the following is an example of a preventive control?
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."
⚠ Common exam trap
Many exam-takers confuse 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.
Answer choices
Why each option matters
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.
Answer analysis
Option-by-option breakdown
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
Guards monitoring observe and report events, which is detective work; they do not physically block entry unless actively enforcing access, which the stem's wording excludes. Tempting because guards can perform prevention when stationed at checkpoints, and that staffing scenario would satisfy a preventive-control requirement.
- ✗
CCTV cameras
Why it's wrong here
CCTV records and deters after the fact; it detects and supports investigation rather than blocking access. It is the right choice for monitoring and evidence gathering. Preventive controls such as locks, bollards or access badges physically stop or restrict entry before an incident occurs.
- ✗
Intrusion detection system
Why it's wrong here
An IDS detects and alerts on intrusions after they occur, so it cannot block or deter access; it is detective, not preventive. It is tempting because it is a physical security system, and it would be the right choice when the requirement is to identify and log unauthorised entry attempts rather than stop them.
- ✓
Mantrap door
Why this is correct
A mantrap door physically constrains entry, allowing only one person through an interlocking chamber at a time. It stops unauthorised tailgating before access occurs, satisfying the stem's requirement for a preventive control rather than a detective or corrective one.
Go deeper
Related to this question
Learn chapter
Identity and Access Management (IAM)
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
Key term
Security control
A security control is a safeguard or countermeasure designed to protect the confidentiality, integrity, and availability of information systems and data.
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Same concept, more angles
1 more way this is tested on CISSP
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?
easy- A.Firewall rules
- ✓ B.Biometric door locks
- C.Security awareness training
- ✓ D.CCTV surveillance cameras
- E.Intrusion detection system (IDS)
Why B: Biometric door locks (B) and CCTV surveillance cameras (D) are both physical security controls. Biometric door locks physically restrict access to a facility or room by verifying unique biological traits (e.g., fingerprints or iris scans). CCTV surveillance cameras provide physical monitoring and surveillance of a facility to detect and record unauthorized physical activity. In contrast, firewall rules (A) and Intrusion Detection Systems (E) are logical/technical controls, while security awareness training (C) is an administrative control.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.