Re: [PEN-TEST] Breaking SSH Listening Ports

["Dunker, Noah" <NDunker () FISHNETSECURITY COM>]

Noah Dunker (a.k.a. a real dork) wrote:

> (FreeBSD)
> ipfw add 1 pass ip from 127.0.0.0/8 in via lo0
> ipfw add 2 deny ip from 127.0.0.0/8

WHOA!!! Clarification, I must have been brain-dead... you must specify a
destination with ipfilter!


(FreeBSD)
ipfw add 1 pass ip from 127.0.0.0/8 to any in via lo0
ipfw add 2 reject ip from 127.0.0.0/8 to any

<Reject works better, too...>

Sorry about that... Wanted to catch it B4 someone else did...

--Noah Dunker




-----Original Message-----
From: MARC A KURTZ [mailto:marck () ESU EDU]
Sent: Thursday, September 14, 2000 2:03 PM
To: PEN-TEST () SECURITYFOCUS COM
Subject: Breaking SSH Listening Ports


(I hope this isn't off-topic)

We are looking into way to break a solution we have that uses SSH to forward
local ports on a Windows box. It uses the option to only bind to 127.0.0.1

My question is, is a hacker able to "break" into the computer and send data
to that loopback address and get the response? Is the loopback completely
non-physical? In other words if a hacker injected 127.0.0.1 packets into the
ethernet card somehow, would the card ignore them, or pass them to the IP
stack?? Will the hacker be able to get the response if it gave one? We are
also assuming there is no PcAnywhere or similiar software installed to take
control of the mouse, keyboard and screen.

Thanks for any insight anyone can give me!

Thank you,
Marc Kurtz