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Date:      Mon, 21 Nov 2005 04:37:23 -0800
From:      ray@redshift.com
To:        Marian Hettwer <MH@kernel32.de>, Peter Jeremy <PeterJeremy@optushome.com.au>
Cc:        freebsd-security@freebsd.org
Subject:   Re: Need urgent help regarding security
Message-ID:  <3.0.1.32.20051121043723.00aa1490@pop.redshift.com>
In-Reply-To: <43819049.5090107@kernel32.de>
References:  <20051121085221.GA4267@cirb503493.alcatel.com.au> <3.0.1.32.20051117232057.00a96750@pop.redshift.com> <43818643.5000206@kernel32.de> <20051121085221.GA4267@cirb503493.alcatel.com.au>

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At 10:15 AM 11/21/2005 +0100, Marian Hettwer wrote:
| Hi there,
| 
| Peter Jeremy wrote:
| > On Mon, 2005-Nov-21 09:33:07 +0100, Marian Hettwer wrote:
| > 
| >>ray@redshift.com wrote:
| >>
| >>>Also, if you have access to the router, it's handy to re-write
| >>>traffic from a higher public port down to port 22 on the server,
| >>>since that will trip up anyone doing scans looking for a connect on
| >>>port 22 across a large number of IP's.
| >>>
| >>
| >>No. That's security by obscurity and doesn't make your system even a wee 
| >>bit more secure.
| > 
| > 
| > It depends what you are guarding against.  If someone wants to get into
| > _your_ system then it's worthless.  OTOH, "you don't have to run faster
| > than the bear, just faster than someone else": Moving your ssh access
| > off port 22 means that someone doing a network scan of port 22 won't
| > see your system.  This is reasonable protection against script kiddies.
| > 
| Where is the protection, or rather the danger in being "visible" to 
| script kiddis? There's no security issue valid for script kiddis which 
| wouldn't be valid for any other attacker too.
| The main question is: Where is the danger in script kiddies with their 
| brute force attacks?
| I guess it's mainly the annoying fact that your logfile get's 
| unreadable. If that's the problem: use logsurfer or something similar to 
| analyze the logfile.
| You just don't get more secure by moving the sshd to a different port 
| than port 22.

The point isn't to get more secure.  You are correct by saying that moving the
port # doesn't make anything more secure.  But why make it easy for someone that
might be doing a scan to find your SSH prompt during a scan that may be focused
on ports 21, 22, 25, 80 and 110?

Along these same lines, we used to even re-compile sshd and remove the welcome
message/version number in the connect.  I know there are two schools of thought
on broadcasting your version numbers on connections, but in the mid 90's, we did
do that from time to time.

Anyway, to each their own :)

Ray




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