Patent ID: 7640585

Claim:
An intrusion detection sensor detecting an attack against a wireless network including an access point providing wireless communication to one or more wireless terminals, the intrusion detection sensor being configured in the wireless network to sense packets between the access point and the one or more wireless terminals and to receive from the access point confirmation information for indicating whether or not the access point has transmitted to a wireless terminal an event packet including critical information on whether or not a wireless connection between the access point and the wireless terminal is established, wherein the intrusion detection sensor examines a packet transmitted and received between the access point and the wireless terminal according to a predetermined detection rule, and when an event packet including critical information on whether or not a wireless line connection between the access point and the wireless terminal is established is examined by the intrusion detection sensor, the event packet is examined by additionally using the confirmation information received from the access point for indicating whether or not the access point has transmitted an event packet, so as to determine the validity of the examined event packet according to whether confirmation information that is associated with the examined event packet and indicates that the access point transmitted the examined event packet is received from the access point.