hardMultiple Choice
ISC2 CC Practice Question: A financial firm has a data center with strict…
A financial firm has a data center with strict access controls. Employees must use smart cards and PINs to enter a mantrapped entrance. Recently, an unauthorized person gained access by following an employee through the mantrapped door (tailgating). The security team reviews logs and finds that the door was opened twice in quick succession, indicating tailgating occurred. The firm wants to implement a solution that prevents tailgating without slowing down authorized access. Which action should they take?
⚠ Common exam trap
ISC2 often tests the distinction between detection (e.g., logs, cameras) and prevention (e.g., turnstiles, mantrap doors), so candidates mistakenly choose biometric or procedural options that only detect or deter rather than physically block tailgating.
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 turnstile that allows only one person per smart card authentication
A turnstile physically enforces one-person-per-authentication by rotating only after a valid smart card read and allowing a single passage, then locking until the next authentication. This directly prevents tailgating without adding delay, as each authorized user passes through at their own pace without needing additional steps like biometric scans or pre-approval.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Require employees to log access requests in advance
Why it's wrong here
Pre-logging access requests creates an approval record but does not physically count or separate people crossing the threshold, so a tailgater still enters behind an approved employee. It is tempting because advance logging supports audit trails and visitor management, yet it leaves the mantrap's single-passage control unenforced.
- ✗
Install a biometric scanner that requires fingerprint and retina scan
Why it's wrong here
Requiring fingerprint plus retina scanning adds a second authentication factor at the same door, so an authenticated employee can still be followed through; it authenticates identity, not the number of bodies passing. It is tempting because biometrics strengthen verification, and would suit replacing lost smart cards, but it does not detect piggybacking.
- ✓
Implement a turnstile that allows only one person per smart card authentication
Why this is correct
A turnstile physically enforces single-person entry per smart card authentication, eliminating the tailgating window that mantrap logs merely detect. It satisfies the requirement to prevent unauthorised entry without impeding authorised staff, since each valid authentication admits exactly one person.
- ✗
Increase the number of security guards at the entrance
Why it's wrong here
Adding guards increases human observation but relies on attention and cannot guarantee one person per authentication, so a determined tailgater still slips through during busy periods. It is tempting because staffing is a quick deterrent, and guards suit low-traffic lobbies, but the mantrap needs an automated single-entry interlock.
Go deeper
Related to this question
Learn chapter
Authentication and Authorization Methods
Key term
Tailgating
Tailgating is a physical security breach where an unauthorized person follows an authorized person into a restricted area without proper authentication.
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 CC 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 CC exam.