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Network Security Secure-Shell
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RE: Illegal user ssh probes

Subject: RE: Illegal user ssh probes
Date: Wed, 29 Sep 2004 10:50:59 -0400 (EDT)
i wrote this to frank directly but the wider group may find it of
interest.  the attack origins are not limited to one geopolitical region:
........
hi frank -
i saw this came up last month on my logs and it was noted on the NetSec
list, which fwd'd the EDUCAUSE Security list msgs:
http://listserv.educause.edu/cgi-bin/wa.exe?A2=ind0408&L=security&T=0&F=&S=&P=11857
http://listserv.educause.edu/cgi-bin/wa.exe?A2=ind0408&L=security&T=0&F=&S=&P=19493

hope this helps    -robert

On Tue, 28 Sep 2004, Huijsmans, JCM (Jan) wrote:

On examining /var/log/secure for several firewalls I manage
remotely using
ssh I have observed a recurrent pattern of probing over the
last several
that attempts to connect using user id's in the following order...

test / guest / admin / admin / user / test

We are seeing the same on 1 of the systems of my private company, coming from 
several systems from the former eastern europe. (mostly 80.x.x.x) In our set 
of users they try are also the user root and an attempt without a user 
(NO_USER or something like that, I don't have access to the logs right now)

However I am wondering if anyone has characterised the probe and/or
performed a risk assessment/analysis?  The rate of probes is
very low so I don't think there is a DOS attack just yet!

Not yet, but on our system we're see a probe pop up every 2-3 hours. (started 
with 1 every 2-3 days)

Is it worth reporting the behaviour to the net block
assignees in case they
aren't aware their server might be compromised?

I think we should at least compare the ip blocks off list to see if there are 
similarities.

Jan Huijsmans


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