easyMultiple ChoiceObjective-mapped
CISSP Practice Question: The security manager for a manufacturing company…
You are the security manager for a manufacturing company with a large facility that houses production servers and sensitive intellectual property. The facility has a single physical entrance that uses a card reader for access control. During a routine audit, you find that the door prop alarm has been bypassed by taping a magnet to the sensor, allowing the door to stay open without triggering an alert. The security guard station is located 200 feet away and does not have a direct line of sight to the door. Which control should you implement FIRST to prevent unauthorized physical access?
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
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Implement a mantrap with two interlocking doors at the entrance.
Implement a mantrap with two interlocking doors. A mantrap is a preventive physical control that effectively prevents tailgating and door propping by requiring one person to authenticate before the second door opens. This directly addresses the bypassed door prop alarm. Option A (biometric scanner) improves authentication but does not prevent door propping. Option B (patrols) is a detective/reactive control and may not catch the propping in time. Option D (video surveillance) is detective, not preventive.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Replace the card reader with a biometric fingerprint scanner.
Why it's wrong here
Replacing a card reader with a biometric fingerprint scanner significantly strengthens the authentication mechanism, ensuring that only authorized individuals can *initiate* the door unlock sequence. However, this enhancement to logical access control does not address the physical vulnerability of the door itself. Once the door is unlocked by an authenticated user, it can still be held open for others to follow (tailgating) or propped open, as the biometric scanner does not control the physical state of the door after authentication.
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Increase the frequency of security patrols around the entrance.
Why it's wrong here
Increasing the frequency of security patrols offers a visible deterrent and a reactive detective control, relying on human observation and intervention. However, patrols are inherently intermittent and cannot guarantee constant, real-time prevention of door propping or tailgating. There will always be gaps in coverage between patrols, during which an unauthorized individual could exploit the vulnerability without immediate detection or physical impedance.
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Implement a mantrap with two interlocking doors at the entrance.
Why this is correct
Implementing a mantrap with two interlocking doors is the most effective preventive control against tailgating and door propping. This system ensures that only one door can be open at a time, physically preventing unauthorized individuals from following an authenticated person through or holding a door open. It forces single-person entry per successful authentication, creating a secure vestibule that actively mitigates both threats by design.
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Install a video surveillance camera to monitor the entrance.
Why it's wrong here
Installing a video surveillance camera provides a valuable detective control, recording incidents of unauthorized access or door propping for later review and forensic analysis. While cameras can act as a deterrent, they do not physically prevent an unauthorized individual from entering or stop someone from propping a door open. The camera merely documents the security breach after it occurs, rather than actively stopping it in real-time.
Go deeper
Related to this question
Learn chapter
Security Governance and Principles
Key term
Access control
Access control is the security practice of determining who or what is allowed to view, use, or enter a resource, and under what conditions.
Key term
Authentication
Authentication is the process of verifying that someone or something is who or what it claims to be before granting access to a system or resource.
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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.