SSH Access Issues

[Wolfgang S. Rupprecht]

"jdow" <jdow at earthlink.net> writes:
> It's possible to configure a firewall to give one shot every three minutes
> to logging in via ssh.

It is possible, but not usually done that way.  

The ssh-attacking programs are pretty good at hammering sshd.  If any
of the users of the machine have a password that is in its attack
dictionary, then your out of luck.  You'd be surprised how many folks
pick utterly crap passwords. When I spot checked a machine I helped
run against a common attack dictionary, a full 15% fell to it.  That
was only a 50k word dictionary too.  The ssh attack programs I saw
could run through that in under a day.

Better would be to just allow RSA (or DSA) and make the attacker guess
a 1024-bit *computer* generated key.

> How long do you think it would take to guess "12345678" as a password
> at one try every three seconds? (Or for the real paranoids one try
> every three minutes.)

Sure, if you use computer generated passwords and they have a
white-noise distribution across the whole search space then you would
also be safe.

-wolfgang
-- 
Wolfgang S. Rupprecht              http://www.full-steam.org/  (ipv6-only)
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