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Date:      Sat, 22 Jan 2000 11:06:36 -0800 (PST)
From:      Pete Carah <pete@ns.altadena.net>
To:        security@freebsd.org
Subject:   RE: Some observations on stream.c and streamnt.c
Message-ID:  <200001221906.LAA83395@ns.altadena.net>

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Well, our (Bay) router is rendered silent (doesn't reboot) just 
routing this attack through itself at around 6k pps.  If aimed at
the router it gets silent faster but never seems to need a reboot (of
course, I don't want to try this too long on the particular router).

This is an ARN at 13.01, should have lots of CPU for 6k pps of this
attack.  I Don't know why just relaying the attack to the other ethernet
has such a dramatic effect.  (about 2k pps get through for a few seconds
then it sleeps completely).

It is not affected if the attack is against a host (fbsd or mac) on the 
same segment, so the "side-effect" multicast, etc packets don't seem to 
be bothering the router, at least not soon...  Don't know what our
upstream sees :-)

We tried this against fbsd (2.2.8-stable, 3.3 and 3.4) with no apparent
results, but "only" at 6k pps for 5-10 mins.  It didn't affect a Mac 
(i-mac at 8.6 or a powerbook at 9.0) at all other than to lengthen the 
ping times about 1/2 msec (tried both to listening and non-listening ports).  
We didn't have time to try windoze or either Cisco.

(I didn't compile this for a "fast" machine, only my laptop which can
only get to 6700 or so pps.)

A flowpoint 2200 DSL router as target with old firmware (1.4.x) is 
affected in an interesting way; it takes ping times from 1msec to around 
7 for 20 pings, then drops about 5 sec of (all) packets, then cycles 
again without rebooting.  Apparently when it runs out of buffers it 
garbage-collects rather slowly and otherwise recovers.  Haven't tried
this on current firmware.

-- Pete


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