[ALUG] "!!" in /etc/passwd

[Stuart Bailey]

Hi Ted,
This may help.

http://www.ncsa.uiuc.edu/UserInfo/Resources/Hardware/IBMp690/IBM/usr/share/man/info/en_US/a_doc_lib/files/aixfiles/passwd.htm


(Ted Harding) wrote:
> Hi Folks,
> 
> Can anyone interpret the following for me?
> I can't find it referred to in 'man' documentation.
> 
> Some "user" entries in /etc/passwd have "!!" in the encrypted
> password field, e.g.
> 
> sshd:!!:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
> rpc:!!:32:32:Portmapper RPC user:/:/sbin/nologin
> 
> mysql:!!:27:27:MySQL Server:/var/lib/mysql:/bin/bash
> postgres:!!:26:26:PostgreSQL Server:/var/lib/pgsql:/bin/bash
> 
> For the acounts which have /sbin/nologin as "shell" I cannot
> of course gain entry, even from root.
> 
> On the other hand, for the accounts (mysql, postgres) which
> have a normal shell, I can 'su' from root without entering a
> password; while if I try to 'su' from any other user I'm prompted
> for a password (which of course does not exist).
> 
> I'm wondering what the full interpretation of the "!!" is.
> I know about "*" in the encrypted password field: there is
> no possible password which encrypts fo "*", so such accounts
> cannot be logged into.
> 
> I've already found out something (see above) about "!!" accounts,
> but is there more that I should know?
> 
> In particular, if I were (as root) to use the 'passwd' command
> to give a "!!" account a real password, would I be treading on
> any toes in the system?
> 
> With thanks,
> Ted.
> 
> --------------------------------------------------------------------
> E-Mail: (Ted Harding) <ted.harding at nessie.mcc.ac.uk>
> Fax-to-email: +44 (0)870 094 0861
> Date: 06-Jun-07                                       Time: 11:53:29
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-- 
---------------------------------------
Stuart Bailey BSc (hons) CEng CITP MBCS
   LinuSoft Ltd. (Managing Director)
           Linux Specialist
            (0845) 6583563
       http://www.linusoft.co.uk
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