IGMP DOS Attack

[D.Stout () EU HNS COM]

  After installing a Snort IDS system on a network link I am responsible 
for , I left it running over night to see how many alerts would be 
generated.
When I returned in the morning I found 450,000 alerts from snort detailing 
a IGMP DoS attack from 6 different source hosts. I cannot find any 
information about this DoS attack (DDoS if you consider 6 hosts at same 
time). 

  Has anybody else had an IGMP DoS attack starting at 5:23 CET ?
  Does anybody know what causes this ?
  What are the implications of this (other than pure bandwidth 
consumption)

  I will continue to search for info, but please help me if you know what 
this is.

Dave Stout
Internet Security Engineer



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