OpenSSH daemon security bug?

[Michael Stone]

On Tue, Jan 05, 2010 at 07:27:00PM +0100, you wrote:
>Password authentication with a weak password is in itself no more secure
>than public key authentication where the private key is protected with a
>weak password. In the former case the attacker only needs to guess the
>password, in the latter case they also need to get the private key.
>Knowledge of the public key does not help an attacker.

You can force the password complexity on the server side. You can't 
force the key management through technical means. That's a very 
important difference. Where this has proven to be a major headache in 
practice is when people have copies of their private keys scattered 
around on various machines, leading to intruders being able to jump from 
one machine to another. (Possibly from one organization to another, 
especially in collaborative environments like .edu's.) Private keys are 
seldom expired on a routine basis, so there may be forgotten copies 
lying about that haven't been used in years. (Should people do this? No.  
Does it happen? Yes. Can you prove none of your users have done it?  
Probably not.) Even with a strong password, there's a big difference 
between a passive offline attack against a key and an active brute force 
of a login password.

Mike Stone