What is tailgating and how can it be mitigated?

• A. Unauthorized person follows an authorized person; mitigations include turnstiles, mantraps, policy, escorting.
• B. A security breach where an intruder follows another into a secure area; mitigations include turnstiles, mantraps, policy, escorting.
• C. A type of vehicle breach at perimeter.
• D. A method of digital authentication.

Answer: (A)

Tailgating is when an unauthorized person follows an authorized individual through an access point into a restricted area. This happens because the system relies on the person’s credential or presence, and the door or entry can be used by more than one person or kept open. To prevent it, implement controls that enforce single-person passage per authentication: turnstiles or mantraps ensure only the person presenting a valid credential gets through, and doors should be monitored so they aren’t propped open. A clear security policy, plus escorting of visitors or unknown individuals when required, reinforces that others cannot enter simply by walking in behind someone. Training staff to challenge or report tailgating and to avoid holding doors for others also helps reduce risk. This concept is about the entry behavior itself, not a vehicle breach or a digital authentication method, which is why the described mitigations fit best.