Passing password in ssh

[Karl Larsen]

Aldo Foot wrote:
> 2008/1/22 Mikkel L. Ellertson <mikkel at infinity-ltd.com>:
>
>   
>> Aldo Foot wrote:
>>     
>>> Well, the scenario I described actually happened years ago to someone I
>>> knew.
>>> If I create keys without a passphrase, and share the public keys between
>>> two systems (A and B), then from system A I can log to system B by
>>> simply saying "ssh user at B". This is very convenient for cron jobs.
>>>
>>> This is particularly risky when the systems are accessed by the general
>>> public.
>>> How does someone finds out the username? I don't know... company
>>>       
>> phonebook,
>>     
>>> online profiles listing first/lastname, etc.
>>>
>>>       
>> You do know that you first have to get the private key of the key
>> pair, right? So you have to crack user at A's account, at least to the
>> point of getting the private key. Remember, the key will not work
>> unless it is only readable by the user. The .ssh directory also
>> needs to be set this way. So just being able to log into machine A
>> is not enough. You also need access to the private key.
>>
>>     
>
> You are correct. My worst nightmare does not include stealing the private
> key. But simply cracking into a user's account who has access to several
> systems containing the keys.
>
> Worst scenario is when someone brakes into a system gains root access
> and does "su - user" to such account and by looking into the .shosts tries
> his luck to other systems.
>
>
>   
>> But even having a pass phrase does not help if someone uses dumb
>> passwords. Things like first name as user name, and last name as
>> password. Then they use their full name as the pass phrase on the
>> key. Or is machine B lets you ssh in using username/password, and
>> you have a user like this. The key is to use the tools responsibly.
>>     
>
>
> Bingo!  There lies my problem.
>
> Perhaps a good practice is to configure accounts such as those for
> cron jobs to use only specific commands.
> Does anyone reading this thread uses such setup?
> I'll play with this a bit.
>
>
>   
>> Mikkel
>> --
>>
>>     
>
>   
    I have some first hand experience with simple passwords. I chose my 
password for my regular account to be very simple. After all no-one can 
use it. WRONG! Someone  did ssh to my system and correctly guessed the 
simple password and never learned the root password but they did some 
childish things.

    That lesson cost nothing and it caused me to use a google type of 
password. Longer than 6 characters with at least one number. I have seen 
what could have been another ssh to me and a few tries at the password 
and gone.

Karl


-- 

	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.
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