RE: Packets from 255.255.255.255(80) (was: Packet from port 80 with spoofed microsoft.com ip)

["greg () optionsinternet com" <greg () optionsinternet com>]

Today we have been receiving on average 380,000 requests an hour TO
255.255.255.255 FROM random IPs. I performed a reverse DNS query on a
sample of 200 hosts, 2 of which came back with hostnames. A ping scan of
the very same 200 hosts showed that only around 20 were *active*.

I contacted our ISP and was told that this traffic was "normal".

Has anyone else seen any similar requests?

Regards

Greg Bolshaw


Original Message:
-----------------
From: Tomasz Papszun tomek-incid () lodz tpsa pl
Date: Thu, 30 Jan 2003 19:03:51 +0100
To: incidents () securityfocus com
Subject: Packets from 255.255.255.255(80) (was: Packet from port 80 with
spoofed microsoft.com ip)


On Thu, 30 Jan 2003 at 14:31:36 +1100, Keith Owens wrote:
> On Wed, 29 Jan 2003 21:46:53 +1100, 
> Michael Rowe <mrowe () mojain com> wrote:
> > I received a packet on my cable modem today, allegedly from
> > microsoft.com: 
> >
> > 18:41:35.663374 207.46.249.190.80 > my.cable.modem.ip.1681:
S866282571:866282571(0) ack 268566529 win 16384 <mss 1460>
> I am seeing a lot of sync/ack packets from port 80 to non-existent
> addresses on my networks.  Somebody is spoofing source addresses to
> attack hosts, we are just innocent victims.  When will ISPs learn that
> they should filter their customer's packets to prevent spoofing?  I am
> even seeing syn/ack packets from 255.255.255.255:80!

Similarly at my networks.
Yesterday evening (Jan 29 21:10 GMT+1) a very noticeable stream of such
packets started to come into my networks.

All are TCP, from 255.255.255.255(80), destined to various random
addresses (even not used) to various port numbers.

This appearance is very noticeable. Before yesterday, single packets
from 255.255.255.255 were coming in rate about one for three weeks.
Since yesterday there have been about 1680 for 22 hours.

-- 
 Tomasz Papszun   SysAdm @ TP S.A. Lodz, Poland  | And it's only
 tomek () lodz tpsa pl   http://www.lodz.tpsa.pl/   | ones and zeros.

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