[Fwd: [IP] New flaw takes Wi-Fi off the air]
-------- Original Message -------- Subject: [IP] New flaw takes Wi-Fi off the air Date: Thu, 13 May 2004 19:25:28 -0400 From: Dave Farber <dave@farber.net> Reply-To: dave@farber.net To: ip@v2.listbox.com Delivered-To: dfarber+@ux13.sp.cs.cmu.edu Date: Thu, 13 May 2004 15:23:54 -0700 From: Dewayne Hendricks <dewayne@warpspeed.com> Subject: [Dewayne-Net] New flaw takes Wi-Fi off the air Sender: dewayne-net@warpspeed.com To: Dewayne-Net Technology List <dewayne-net@warpspeed.com> New flaw takes Wi-Fi off the air By Patrick Gray, Security Focus (drew.cullen@theregister.co.uk) 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> ------------------------------------- You are subscribed as suresh@hserus.net To manage your subscription, go to http://v2.listbox.com/member/?listname=ip Archives at: http://www.interesting-people.org/archives/interesting-people/
On Fri, 14 May 2004 05:21:39 +0530, Suresh Ramasubramanian <suresh@outblaze.com> said:
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.
Wow. I'm underwhelmed. First, we collectively realize that RFC793 really HAS said 'The RST has to be in the window, not dead on' for 2 decades. Now somebody's discovered that a jabbering transciever can take out a CSMA/CA network. And to top it off: 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) Yes - *THIS* attack doesn't work, you can't take down a 802.11a net with a hacked PDA that jabbers on channel, you need to use a hacked 802.11a-capable PDA that jabbers on all the subchannels at once. ;) Any bets on what will be rediscovered next? Some CERT will realize that if a DDoS uses RFC1918 source addresses, it will be hard to track down the misbehaving sources? ;)
## On 2004-05-13 21:43 -0400 Valdis.Kletnieks@vt.edu typed:
Any bets on what will be rediscovered next? Some CERT will realize that if a DDoS uses RFC1918 source addresses, it will be hard to track down the misbehaving sources? ;)
No - then someone would have to re-invent backscatter analysis ... ;-) -- Rafi
Rafi Sadowsky writes on 5/14/2004 11:28 PM:
## On 2004-05-13 21:43 -0400 Valdis.Kletnieks@vt.edu typed:
Any bets on what will be rediscovered next? Some CERT will realize that if a DDoS uses RFC1918 source addresses, it will be hard to track down the misbehaving sources? ;)
No - then someone would have to re-invent backscatter analysis ... ;-)
And someone would then start another thread about BCP 38 on nanog ... funny how several threads turn into a thread about spoofed source address filtering in no time at all :) srs -- suresh ramasubramanian suresh@outblaze.com gpg EDEDEFB9 manager, security and antispam operations, outblaze ltd
Suresh Ramasubramanian wrote:
And someone would then start another thread about BCP 38 on nanog ... funny how several threads turn into a thread about spoofed source address filtering in no time at all :)
Let the record reflect the fact that it was not I who did that this time. I forgot where the grease spot (from the oft-beaten horse) was. -- Requiescas in pace o email Ex turpi causa non oritur actio http://members.cox.net/larrysheldon/
On Fri, May 14, 2004 at 05:21:39AM +0530, Suresh Ramasubramanian wrote:
-------- Original Message --------
New flaw takes Wi-Fi off the air . . . AusCERT senior security analyst Jamie Gillespie does not anticipate the wide exploitation of the vulnerability.
I can think of one application - the next time I'm presenting at a conference where everyone has their heads buried in their laptops, I know what I'll be running on my machine at the podium ;) Bill.
I can think of one application - the next time I'm presenting at a conference where everyone has their heads buried in their laptops, I know what I'll be running on my machine at the podium ;)
what keeps the cows in the pasture is the quality of the grass not the height of the fence. randy
Isn't that directly related to the number of cow-chips on the pasture? On May 14, 2004 Randy Bush spake:
what keeps the cows in the pasture is the quality of the grass not the height of the fence.
randy
-- Rich Sena - ras@thick.net ThickNET Consulting "On the way to understanding; you understand, and forget."
Randy Bush writes on 5/14/2004 7:13 PM:
I can think of one application - the next time I'm presenting at a conference where everyone has their heads buried in their laptops, I know what I'll be running on my machine at the podium ;)
what keeps the cows in the pasture is the quality of the grass not the height of the fence.
You can take a horse to water, but you can't make it drink. yours, etc. -- suresh ramasubramanian suresh@outblaze.com gpg EDEDEFB9 manager, security and antispam operations, outblaze ltd
what keeps the cows in the pasture is the quality of the grass not the height of the fence. You can take a horse to water, but you can't make it drink.
i am greatly cheered by non-listening competitors. we have actually watched nanog/ietf/... traffic levels, and one can clearly tell when there is an interesting talk/speaker; net use drops non-trivially. the bottom line is that, if you want people to listen to you, then have something interesting to say and say it well. and just being cute doesn't cut it. randy
----- Original Message ----- From: "Bill Owens" <owens@nysernet.org>
I can think of one application - the next time I'm presenting at a conference where everyone has their heads buried in their laptops, I know what I'll be running on my machine at the podium ;)
Bill.
Wayback before laptops, an old hand at IBM stopped in the middle of his presentation and said, "If you guys get done listening before I get done talking, please let me know so I can leave." --Michael
participants (8)
-
Bill Owens -
Laurence F. Sheldon, Jr. -
Michael Painter -
Rafi Sadowsky -
Randy Bush -
Rich Sena -
Suresh Ramasubramanian -
Valdis.Kletnieks＠vt.edu