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Re: [nsp] known networks for broadcast ping attacks
From: "Alex.Bligh" <amb () xara net>
Date: Thu, 31 Jul 1997 09:32:22 +0100

At 7:56 PM +0100 7/30/97, Alex.Bligh wrote:
Urm, is the MAE-East LAN ?! Are you saying attacks are
being mounted from here or people are attacking this LAN (not
sure which is more worrying)

The LAN is being used indirectly to attack another network.  Pings are
spoofed as originating from the machine that is being attacked and sent to
the broadcast address on another network.  This causes every machine on the
receiving network to send an ECHO_RESPONSE to the machine being attacked,
esentially creating a huge multiplying effect on a ping flood attack.

Apparently, the MAE-East LAN is one of the networks that attackers are
using to flood other hosts.

Right. Well that's how I read it too. And just to make sure this thread
is indeed operations related, I'll make the following points:

1. Send a Cisco enough (a thousand a second) ICMP ECHO REQUESTS, and
   it takes CPU to 99% and drops all BGP sessions. Tested on a C7010.

2. Various routers on MAE-East have been mysteriously clearing all their
   BGP peers over the past week or two.

3. The attack mentioned causes a lot of ICMP ECHO REQUESTS to be sent
   to Cisco routers on MAE-East.

Are these facts by any chance related? I think we should be told. Or,
urm, find out. On with that logging ACL.

Alex Bligh
Xara Networks

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