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Re: adduser: what is the difference between --disabled-password and--disabled-login



On Wed, 11 May 2005 01:40:33 +0300, Shaul Karl <shaulk@013.net> wrote:
>The way I understand it, the effect of ! or * is identical.

No.

>Alternatively, the difference is set by the configuration of pam, which,
>I believe, is out of adduser scope. This match my experience that login
>through SSH RSA key is possible even if a '!' is used.
>  In any case, am I right that adduser's --disabled-login and 
>--disabled-password looks to be the same?

Once again, it is "UsePam yes" in the default /etc/ssh/sshd_config
which breaks things.

If that option is switched off, an account created with adduser
--disabled-login is impossible to ssh into (log entry "sshd[14704]:
User testuser not allowed because account is locked") while an account
created with adduser --disabled-password can ssh in fine via
authorized_keys.

"UsePam yes" is generally a _big_ surprise for the local admin since
it allows passwords to be used even if "UsePasswordAuthentification
no" is set in sshd_config.

Looks like we have just found the second security option which is
broken by "UsePam yes". Bad, very bad.

Greetings
Marc

-- 
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Marc Haber         |   " Questions are the         | Mailadresse im Header
Mannheim, Germany  |     Beginning of Wisdom "     | http://www.zugschlus.de/
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