A clear channel assessment attack or Queensland attack is a

physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechani ...

DoS attack against

Wi-Fi Wi-Fi () is a family of wireless network protocols based on the IEEE 802.11 family of standards, which are commonly used for Wireless LAN, local area networking of devices and Internet access, allowing nearby digital devices to exchange data by ...

networks. The attack focuses the need of a wireless network to receive the "clear channel assessment"; which is a function within

CSMA/CA Carrier-sense multiple access with collision avoidance (CSMA/CA) in computer networking, is a link layer multiple access method in which carrier sensing is used. Under CSMA/CA, nodes attempt to avoid collisions by beginning transmission only af ...

to determine whether the wireless medium is ready and able to receive data, so that the transmitter may start sending it. The attack makes it appear that the airwaves are busy, which basically puts the entire system on hold. The attack works only on 802.11b, and is not effective on the OFDM-based protocols 802.11g and 802.11a. However, some hybrid 802.11b/g access points will hinder the 802.11g network when the 802.11b network is attacked.

Discovery

The attack was originally discovered by researchers at

Queensland University of Technology The Queensland University of Technology (QUT) is a public university, public research university located in the city of Brisbane in Queensland, Australia. It has two major campuses, a modern city campus in Gardens Point, Brisbane, Gardens Point ...

's Information Security Research Center, thus it is where the name ''Queensland attack'' comes from.

In practice

The signal telling the system the airwaves are busy is of course sent through the attacker's

NIC Nic is a gender-neutral given name, often short for Nicole, Nicholas, Nicola, or Dominic. It is also a component of Irish-language female surnames. It may refer to: Arts and entertainment * Nic Dalton (born 1964), Australian musician * Nic En ...

, by placing it in continuous transmit mode. The attack can be set up through the use of the Intersil's Prism Test Utility (PrismTestUtil322.exe).

References

{{reflist Computer security exploits