How to Prevent Tailgating Attacks: Mantrap vs Other Controls
You are a security consultant for a mid-sized company with 500 employees. The company has a secure data center with a biometric access control system. Recently, a contractor was able to enter the data center without authorization by claiming he forgot his badge and an employee held the door for him. The contractor then accessed sensitive servers and exfiltrated data. The company wants to prevent such incidents. Which physical security control would be most effective in preventing this type of attack?
Quick Answer
The answer is a mantrap with biometric and badge authentication. This physical security control is most effective because it enforces strict two-person authentication, requiring both the contractor and the employee to independently verify their identities before the mantrap doors unlock, thereby eliminating the social engineering vector of tailgating. On the Certified Ethical Hacker CEH exam, this scenario tests your understanding of layered physical security and the specific weakness of single-factor biometric systems when combined with human courtesy. A common trap is choosing a simple turnstile or security guard, but these fail to prevent piggybacking when an employee holds the door. Remember the memory tip: “Mantrap means one trap per person”—each authentication cycle allows only one individual to pass, directly blocking unauthorized entry.
⚠ Common exam trap
A common mix-up: candidates choose CCTV or guards because they seem like obvious physical security measures, but the question specifically targets tailgating/piggybacking, which only a mantrap with dual authentication can reliably prevent.
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
✓
Implement a mantrap with biometric and badge authentication.
A mantrap with biometric and badge authentication enforces strict two-person authentication: both the contractor and the employee must independently authenticate before the mantrap doors unlock. This prevents tailgating (piggybacking) by ensuring only one person enters per authentication cycle, eliminating the social engineering vector where an employee holds the door for an unauthorized individual.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Install CCTV cameras to monitor the entrance.
Why it's wrong here
CCTV is detective, not preventive.
- ✗
Require employees to wear RFID badges at all times.
Why it's wrong here
Badges do not prevent tailgating.
- ✓
Implement a mantrap with biometric and badge authentication.
Why this is correct
Mantraps physically prevent tailgating by requiring one person at a time.
- ✗
Hire additional security guards at the entrance.
Why it's wrong here
Guards can be socially engineered.
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Same concept, more angles
1 more way this is tested on CEH
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 effective physical security controls to prevent tailgating?
hard- A.Biometric door lock
- ✓ B.Mantrap
- C.CCTV cameras
- D.Security guard
- ✓ E.Turnstile with one-way access
Why B: A mantrap is a physical security control consisting of two interlocking doors that create a small vestibule. Only one door can be opened at a time, and the system verifies that only one person enters before allowing the second door to open. This design directly prevents tailgating by trapping unauthorized individuals who attempt to follow an authorized person through the first door.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CEH practice question is part of Courseiva's free EC-Council 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 CEH exam.