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RE: The impending DDoS storm

  • From: Josh Fleishman
  • Date: Thu Aug 14 11:27:22 2003



Has anyone determined a method for triggering the DOS attack manually?
We've attempted this by changing an infected machine's clock, however it
did not work on our test box.  If anyone has triggered the attack, do
you have a copy of the sniffed data stream?  

It sounds like uRPF is going to be of very little benefit to blocking
the attack if the spoofed addresses come from the infected host's
subnet/parent subnet.

-Josh

-----Original Message-----
From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of
Mark Vallar
Sent: Wednesday, August 13, 2003 7:18 PM
To: nanog@merit.edu
Subject: Re: The impending DDoS storm




Jack Bates Wrote:

> I have no affiliation with Microsoft, nor do I care about their
> services or products. What I do care about is a worm that sends out 
> packets uncontrolled. If there is the possibility that this "planned" 
> DOS will cause issues with my topology, then I will do whatever it 
> takes to stop it. The fact that user's can't reach windowsupdate.com 
> is irrelevant.
>

There will most likely be issues with a lot of networks.

I had a glimpse of what is to come on the 16th on Tuesday.  We have a
firewall customer that had an infected machine behind the firewall and
the RTC clock was set incorrectly to 8/16.  The firewall was *logging*
~50 attempts per second trying to connect on port 80 to
windowsupdate.com. Since the worm was sending from a spoofed source
address the firewall was denying the packets.  This customers network is
a /24 out of traditional Class B space and I was seeing random source
addresses from almost every IP out of the /16.

This is not a forensic analysis, just what I observed in the firewall
logs.

Is it a coincidence that 8/16 is a Saturday....I think not.  A lot less
personal on-site to deal with possible issues.

-Mark Vallar








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