[Full-Disclosure] (AUSCERT AA-2004.02) AUSCERT Advisory - Denial of Service Vulnerability in IEEE 802.11 Wireless Devices (fwd)

Valdis.Kletnieks at vt.edu Valdis.Kletnieks at vt.edu
Thu May 13 22:52:03 BST 2004


On Thu, 13 May 2004 20:36:47 +0200, Gunter Luyten <gunter.lists at haxor.be>  said:

> > 	The model of a shared communications channel is a fundamental
> > 	factor in the effectiveness of an attack on this vulnerability.
> > 	For this reason, it is likely that devices based on the newer IEEE
> > 	802.11a standard will not be affected by this attack where the
> > 	physical layer uses Orthogonal Frequency Division Multiplexing
> > 	(OFDM).
> 
> That might be possible indeed, but this confirms to me that this 
> "vulnerability" is based upon radio physics rather than shortcomings in 
> the CSMA/CA protocol.

What they're saying here is "We'll not be affected by *THIS* attack (the one
that transmits on 1 frequency per channel)".  A moment's pondering will
show that all you have to do is apply the same attack to the 48 OFDM subcarriers
at once.  In other words, just a little more challenging.  (Remember, every
single card that does OFDM has the circuitry to handle this already on it).

So no, you can't take down an OFDM with a PDA that does 802.11b.

You have to get a PDA that has an OFDM-capable card. :)
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