Relay Attack
Noun · Security & Infosec
Definitions
An attack in which communications between a legitimate party and a trusted system are forwarded through an attacker-controlled channel so proximity or direct-contact assumptions are bypassed. Relay attacks are common in contactless cards, NFC, wireless entry systems, and some challenge-response protocols.
In plain English: An attack that forwards a real authentication exchange to trick a system into accepting it.
Example: "The badge clone did not need the secret key because the relay attack simply forwarded the live authentication exchange from a distance."