Bugtraq mailing list archives

Re[2]: Skype Network Remote DoS Exploit


From: "Matthew Leeds" <mleeds () theleeds net>
Date: Mon, 20 Aug 2007 14:50:30 -0700

I'd consider this uh, untrue. Didn't happen on the last patch Tuesday, nor the one before. What made this month 
special? Did those millions of Windows users who update all coordinate their activity? Not likely.

As to other services that depends on running on consumers computers to provide services, there are not many on the 
scale of Skype that vampire bandwidth and CPU in the same way. Certainly none of the bit torrent networks crashed, but 
then I suspect that they are far more tolerant of user's computers coming and going, and far less dependent on their 
persistence.

----------
---Matthew
*********** REPLY SEPARATOR  ***********

On 8/20/2007 at 1:39 PM Steven M. Christey wrote:

The outage being experienced by Skype was apparently due to massive
simultaneous reboots and reconnects after systems installed their
Windows patches.

from http://heartbeat.skype.com/2007/08/what_happened_on_august_16.html:

  The disruption was triggered by a massive restart of our users'
  computers across the globe within a very short timeframe as they
  re-booted after receiving a routine set of patches through Windows
  Update.

  The high number of restarts affected Skype's network resources.
  This caused a flood of log-in requests, which, combined with the
  lack of peer-to-peer network resources, prompted a chain reaction
  that had a critical impact.

I wonder how many other services are impacted by simultaneous Windows
scheduled updates.

Anyway... given that this was going on at the time the SecurityLab.ru
exploit was released, and the exploit only claims a DoS (and only
seems to make a series of requests to long URIs), was the exploit
actually effective, or was the "DoS" just part of the larger outage?

- Steve




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