Re: DOS by Flooding a Network

From: Skip Carter (skipat_private)
Date: Mon Jun 17 2002 - 15:24:31 PDT

  • Next message: W.G. Iyer: "Re: DOS by Flooding a Network"

    > This past weekend, we experienced the periodic flooding of our network.
    > The flooding caused our network to be inaccessible. The traffic has
    > mainly been ICMP: large quantities of large spoofed packets...similar to
    > "ping-of-death. Appropriate patching has been applied so the actual
    > attach does not shut anything down. However, it does succeed in flooding
    > of our network rendering it inaccessible.
    > 
    > We are trying to figure out a way, if any, to mitigate this attack from
    > flooding our network in the future. We tried to coordinate with our ISP
    > upstream but they say they can't do anything....and we feel sending
    > resets on our end would be useless and ineffective. We are trying to
    > figure out a way to eliminate the "choke point" or "bottle neck" when
    > the attacks occur. I feel we should be able to do something better than
    > just "weathering the storm".
    
    	We have been seeing the same type of thing here, it started almost a week ago 
    and became
    very heavy over the weekend.  The packets almost look like a classical Smurf 
    storm, but the
    destination IP is 255.255.255.255.  This morning I created a Snort rule to 
    record what is
    happening and so far I have seen 77 different supposed source addresses (which 
    are almost
    certainly spoofed).   Fortunately for me, my ISP is cooperating in trying to 
    deal with these
    events.
    
    
    
    
    
     
    
    
    -- 
     Dr. Everett (Skip) Carter      Phone: 831-641-0645 FAX:  831-641-0647
     Taygeta Scientific Inc.        INTERNET: skipat_private
     1340 Munras Ave., Suite 314    WWW: http://www.taygeta.com
     Monterey, CA. 93940            
    
    
    
    
    
    
    
    
    
    
    
    
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