[IP] another important flaw in ethernet -- New flaw takes Wi-Fi off the air
Delivered-To: dfarber+@xxxxxxxxxxxxxxxxxx
Date: Thu, 13 May 2004 23:39:24 -0400
From: "Patrick W.Gilmore" <patrick@xxxxxxxxx>
Subject: Re: [IP] New flaw takes Wi-Fi off the air
To: dave@xxxxxxxxxx
Cc: "Patrick W.Gilmore" <patrick@xxxxxxxxx>
Dave,
Our team has just spent an enormous amount of time and money in intensive
study and we have confirmed that - you may not believe this - if you cut
the ethernet cable between your computer and the wall (wait for it): YOUR
COMPUTER WILL LOSE ITS NETWORK CONNECTIVITY!
We think this deserves the widest possible distribution, so please publish
to IP. We plan to do a press release, and hopefully get DHS on the band
wagon. We are sure other countries will follow suit quickly.
Did that sound a bit obvious and alarmist? Perhaps even a little
silly? Now you know exactly how any network professional felt reading the
release below.
Some of my friends then say, "Yes, but we are not all network professionals
so we do not know this stuff." Well, if you are not knowledgeable in a
field, why do you feel competent to discuss what is alarming or not? There
are probably hundreds of drugs I've never even heard of which would kill
you very quickly, but I do not take space in medical journals warning
doctors of what they already know. And if I took space in a newspaper
saying the same thing, doctors would laugh out loud, or more likely shake
their heads in bewilderment.
Why have we suddenly had a rash of "announcements" stating the obvious? It
is causing a lot of light and heat, but no fire. Oh, and it is wasting a
lot of people's time as people ask their local professional to comment on
the newest "vulnerability".
--
TTFN,
patrick
On May 13, 2004, at 7:25 PM, Dave Farber wrote:
Delivered-To: dfarber+@xxxxxxxxxxxxxxxxxx
Date: Thu, 13 May 2004 15:23:54 -0700
From: Dewayne Hendricks <dewayne@xxxxxxxxxxxxx>
Subject: [Dewayne-Net] New flaw takes Wi-Fi off the air
Sender: dewayne-net@xxxxxxxxxxxxx
To: Dewayne-Net Technology List <dewayne-net@xxxxxxxxxxxxx>
New flaw takes Wi-Fi off the air
By Patrick Gray, Security Focus (drew.cullen@xxxxxxxxxxxxxxxxx)
Published Thursday 13th May 2004 21:29 GMT
<http://www.theregister.co.uk/2004/05/13/wifi_security_flaw/>
A newly-discovered vulnerability in the 802.11 wireless standard allows
attackers to jam wireless networks within a radius of one kilometre using
off-the-shelf equipment.
Affecting various hardware implementations of the IEEE 802.11 wireless
networking standard - including widely used 802.11b devices - the flaw was
found in the collision avoidance routines used to prevent multiple devices
from transmitting at the same moment.
"When under attack, the device behaves as if the channel is always busy,
preventing the transmission of any data over the wireless network," a
security advisory (http://www.auscert.org.au/render.html?it=4091) released
by AusCERT reads.
The weakness allows miscreants to take down networks within five seconds,
according to researchers at Australia's Queensland University of
Technology's Information Security Research Centre (ISRC), which discovered
the vulnerability.
ISRC's leader of network and systems security research, Associate
Professor Mark Looi, whose PhD students, Christian Wullems, Kevin Tham and
Jason Smith discovered the flaw, said any organization that relies heavily
on wireless infrastructure should take the threat seriously.
"Anyone who's relying on the availability of a wireless network should
really consider that their wireless network can be knocked offline at any
time," said Looi. "They need to very seriously evaluate that network and
decide if it's possible to move away from wireless technology."
While previous denial of service attacks against wireless networks have
required specialised hardware and relied on high-power antennas, the new
attack will make knocking a wireless network off the air an option for a
"semi-skilled" attacker using standard hardware.
"An attacker using a low-powered, portable device such as an electronic
PDA and a commonly available wireless networking card may cause
significant disruption to all WLAN traffic within range, in a manner that
makes identification... of the attacker difficult," The AusCERT advisory read.
Because the flaw is in the 802.11 protocol itself, the vulnerability
cannot be mitigated through the use of software or encryption schemes.
Replacing wireless devices with those not affected by the flaw seems the
only option, said Looi.
"Mitigation strategies are few and far between," Looi said "Organisations
could deploy wireless networks that don't use this technology, [but] it
will be a very expensive exercise."
The flaw is only present in devices using a Direct Sequence Spread
Spectrum (DSSS) physical layer, including IEEE 802.11, 802.11b and 802.11g
wireless devices operating at low speed. 802.11a and 802.11g wireless
devices configured to operate at speeds above 20Mbps are not affected by
the glitch,
AusCERT senior security analyst Jamie Gillespie does not anticipate the
wide exploitation of the vulnerability.
"For the average corporate user, we're not expecting to see ongoing denial
of service attacks. However, if you have remote equipment that is only
connected through wireless it is possible that the connection could be
disrupted," Gillespie said. "Some critical infrastructure providers may
not deploy wireless... but if any do then they should be looking at
mitigation strategies."
The lack of a "measurable result" during an attack is likely to render the
average attacker bored, Gillespie added.
Unlike flaws discovered in the WEP encryption scheme, the newly-disclosed
vulnerability will not allow an attacker to snoop on network communications.
The ISRC findings will be presented to the Institute of Electrical and
Electronic Engineers (IEEE) Wireless Telecommunication Symposium in
California on Friday.
Archives at: <http://Wireless.Com/Dewayne-Net>
Weblog at: <http://weblog.warpspeed.com>
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