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Date:      Wed, 24 Jul 2002 13:14:49 -0700
From:      Eli Dart <dart@nersc.gov>
To:        twig les <twigles@yahoo.com>
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re: SSH problem (was ssh cipher) 
Message-ID:  <20020724201450.8DAD63B1AD@gemini.nersc.gov>
In-Reply-To: Message from twig les <twigles@yahoo.com>  of "Wed, 24 Jul 2002 12:33:25 PDT." <20020724193325.92208.qmail@web10107.mail.yahoo.com> 

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I seem to remember encountering something like this some time ago.

Do you have tcp wrappers configured to display a banner?   I think 
this was what caused the problem for me -- the banner that tcp 
wrappers injected fouled up the ssh protocol negotiations.

I could be wrong about this....memory is fuzzy today...

		--eli


In reply to twig les <twigles@yahoo.com> :

> Well the problem isn't ssh.com vs openssh.  I sshed
> from the pos box to my sniffer and got in, but
> couldn't ssh back again.  This is the verbose output
> from the session from the pos to the sniffer:
> 
> <snip>
> # ssh -v -v -v -l snort 10.x.x.x
> OpenSSH_2.5.1p2, SSH protocols 1.5/2.0, OpenSSL
> 0x0090600f
> Contains Cisco Secure Intrusion Detection System
> modifications.
> Domestic strength encryption. (k9).
> debug: Reading configuration data /etc/ssh_config
> debug: ssh_connect: getuid 0 geteuid 0 anon 0
> debug: Connecting to 10.20.0.124 [10.20.0.124] port
> 922.
> debug: Allocated local port 1023.
> debug: Connection established.
> debug: identity file /root/.ssh/identity type 3
> debug: identity file /root/.ssh/id_dsa type 3
> debug: Remote protocol version 1.99, remote software
> version OpenSSH_2.3.0 FreeBSD localisations 20010713
> debug: match: OpenSSH_2.3.0 FreeBSD localisations
> 20010713 pat ^OpenSSH_2\.3\.0
> debug: Local version string SSH-1.5-OpenSSH_2.5.1p2
> debug: Waiting for server public key.
> debug: Received server public key (768 bits) and host
> key (1024 bits).
> <snip>
> debug: Encryption type: 3des
> debug: Sent encrypted session key.
> debug: Installing crc compensation attack detector.
> debug: Received encrypted confirmation.
> debug: Doing password authentication.
> snort@10.x.x.x's password: 
> <snip>
> 
> 
> But when sshing back, I got the following:
> 
> 
> %ssh -c 3des-cbc -v -v -v 10.20.0.90
> SSH Version OpenSSH_2.3.0 FreeBSD localisations
> 20010713, protocol versions 1.5/2.0.
> Compiled with SSL (0x0090601f).
> debug: Reading configuration data /etc/ssh/ssh_config
> debug: ssh_connect: getuid 1001 geteuid 1001 anon 1
> debug: Connecting to (null) [10.20.0.90] port 22.
> debug: Connection established.
> ssh_exchange_identification: Connection closed by
> remote host
> debug: Calling cleanup 0x8058204(0x0)
> <snip>
> 
> Things I've ruled out:
> Incompatibility with ssh.com and openssh (can ssh from
> sniffer to ssh.com boxes).
> Wrong user
> Wrong listening port
> Unallowed source IP (I can telnet in, but not SSH)
> Wrong cipher - it's using 3des
> 
> Am I destined to bang my head on the desk and load
> Warcraft 3?
> 
> 
> --- Peter Pentchev <roam@ringlet.net> wrote:
> > On Wed, Jul 24, 2002 at 11:02:09AM -0700, twig les
> > wrote:
> > > All, I have a POS box running an old version of
> > > openssh (not allowed to upgrade it, sigh).  Right
> > now
> > > our jumpoff point is running ssh.com software and
> > gets
> > > the following error immediately:
> > > 
> > > ssh 1.1.1.1
> > > warning: Authentication failed.
> > > Disconnected; connection lost (Connection
> > closed.).
> > > 
> > > I've tried specifying the user and even the port
> > but I
> > > think the problem may be that the openssh (2.5 i
> > > think) may not be using the correct cipher.  How
> > do I
> > > check what cipher this guy is using?  Also, this
> > box
> > > has got to be logging the connections attempts
> > > somewhere, but I haven't seen it.
> > 
> > Does the ssh.com SSH client have something
> > resembling
> > the OpenSSH client's "-v" command-line option, and
> > especially its "-v -v -v" functionality? :)
> > 
> > G'luck,
> > Peter
> > 
> > -- 
> > Peter Pentchev	roam@ringlet.net	roam@FreeBSD.org
> > PGP key:
> > http://people.FreeBSD.org/~roam/roam.key.asc
> > Key fingerprint	FDBA FD79 C26F 3C51 C95E  DF9E ED18
> > B68D 1619 4553
> > No language can express every thought unambiguously,
> > least of all this one.
> > 
> 
> > ATTACHMENT part 2 application/pgp-signature 
> 
> 
> 
> =====
> -----------------------------------------------------------
> All warfare is based on deception.
> -----------------------------------------------------------
> 
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