|
Clear Channel Assessment Attack
A clear channel assessment attack or Queensland attack is a physical layer DoS attack against Wi-Fi networks. The attack focuses the need of a wireless network to receive the "clear channel assessment"; which is a function within CSMA/CA 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'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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequencies to transmit on, the line code to use and similar low-level parameters, are specified by the physical layer. At the electrical layer, the physical layer is commonly implemented in a dedicated PHY chip or, in electronic design automation (EDA), by a design block. In mobile computing, the MIPI Alliance *-PHY family of interconnect protocols are widely used. Role The physical layer defines the means of transmitting a stream of raw bits over a physical data link connecting network nodes. The bitstream may be grouped into code words or symbols and converted to a physical signal that is transmitted over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DoS Attack
In computing, a denial-of-service attack (DoS attack) is a cyberattack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. The range of attacks varies widely, spanning from inundating a server with millions of requests to slow its performance, overwhelming a server with a substantial amount of invalid data, to submitting requests with an illegitimate IP address. In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack; simply attempting to block a single source is insufficient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
