802.11b (others) single packet DoS

[michaeltone1975 <michaeltone1975 () telstra com>]

http://www.auscert.org.au/render.html?it=4091

The vulnerability is related to the medium access control (MAC)
function of the IEEE 802.11 protocol.  WLAN devices perform Carrier
Sense Multiple Access with Collision Avoidance (CSMA/CA), which
minimises the likelihood of two devices transmitting
simultaneously.  Fundamental to the functioning of CSMA/CA is the
Clear Channel Assessment (CCA) procedure, used in all
standards-compliant hardware and performed by a Direct Sequence
Spread Spectrum (DSSS) physical (PHY) layer.

An attack against this vulnerability exploits the CCA function at
the physical layer and causes all WLAN nodes within range, both
clients and access points (AP), to defer transmission of data for
the duration of the attack. When under attack, the device behaves
as if the channel is always busy, preventing the transmission of
any data over the wireless network.


http://standards.ieee.org/getieee802/download/802.11-1999.pdf





                                                                      

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