Date: Wed, 5 Dec 2001 11:57:29 -0700 From: John Reynolds~ <jreynold@sedona.ch.intel.com> To: freebsd-stable@FreeBSD.ORG Subject: Re: naive security question Message-ID: <15374.28185.485112.113662@chlx169.ch.intel.com> In-Reply-To: <20011205184000.GA21710@sploo.aagh.net> References: <20011205174654.93719.qmail@web21009.mail.yahoo.com> <20011205184000.GA21710@sploo.aagh.net>
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[ On Wednesday, December 5, Thomas Hurst wrote: ]
>
> If you want to remove the password guessing bit, disable it and use
> RSA/DSA keys instead. Also the general consensus would seem to be to
> stick to SSH2 if you're really that worried.
you can also go one step further and put more "constraints" on the keys in
your authorized_keys and authorized_keys2 files.
from sshd(8):
from="pattern-list"
Specifies that in addition to RSA authentication, the canonical
name of the remote host must be present in the comma-separated
list of patterns (`*' and `'? serve as wildcards). The list may
also contain patterns negated by prefixing them with `'!; if the
canonical host name matches a negated pattern, the key is not
accepted. The purpose of this option is to optionally increase
security: RSA authentication by itself does not trust the network
or name servers or anything (but the key); however, if somebody
somehow steals the key, the key permits an intruder to log in
from anywhere in the world. This additional option makes using a
stolen key more difficult (name servers and/or routers would have
to be compromised in addition to just the key).
So you can specify which machines you can SSH from (if you can narrow down
the set of "authorized hosts" from which you can ssh into your box from).
A sample of my file:
from="somehost.foo.bar.com" 1024 35 16503156<rest of big freaking number>
So, now even if somebody stole that key and could use it to try and
authenticate with it, unless they can also present themselves as
somehost.foo.bar.com, it won't work.
Anyway, 'only the paranoid survive' :)
-Jr
--
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| John Reynolds WCCG, CCE, CDS - Senior CAD Engineer |
| Intel Corporation MS: CH6-210 Phone: 480-554-9092 pgr: 602-868-6512 |
| jreynold@sedona.ch.intel.com http://www-aec.ch.intel.com/~jreynold/ |
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