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Re: Orphaned User Accounts?



On 11/2/2010 3:09 PM, Carlos Mennens wrote:
[snip]
> 
> man:x:6:12:man:/var/cache/man:/bin/sh
man has its own user. Really!
> lp:x:7:7:lp:/var/spool/lpd:/bin/sh
For printer daemon, as well as a few other things
> mail:x:8:8:mail:/var/mail:/bin/sh
system mail needs a user.
> news:x:9:9:news:/var/spool/news:/bin/sh
linked with above, usually
> uucp:x:10:10:uucp:/var/spool/uucp:/bin/sh
Ditto.
> proxy:x:13:13:proxy:/bin:/bin/sh
Not sure.
> www-data:x:33:33:www-data:/var/www:/bin/sh
Apache2 will run as this user. Most /any/ httpd will.
> backup:x:34:34:backup:/var/backups:/bin/sh
used for Bacula, DeJa Dup and friends.
> list:x:38:38:Mailing List Manager:/var/list:/bin/sh
mailman, mlmmj,etc.
> irc:x:39:39:ircd:/var/run/ircd:/bin/sh
used by ircd.
> gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh
GNATS runs as a user.
> libuuid:x:100:101::/var/lib/libuuid:/bin/sh
LibUUID needs a user to run as to keep track of some things IIRC. I may
be wrong.
> 
> I'm trying to understand why Debian developers slip in 'games', 'lp',
> 'news', 'uucp', 'www-data', 'list', 'irc', etc etc etc. Now if I
> install 'Apache', 'CUPS', 'Exim/Postfix', etc etc etc then I
> understand why those accounts would appear but why do these accounts
> appear in a fresh minimal installation with no trace of their
> respected packages? I also label them as 'orphaned' because if you try
> to remove the user and their default home directory, you get an error
> that those directories don't exist. For example:

They aren't orphaned at all. They're just /user declarations/ used by
some daemons, startup scripts, etc.

There's also users like Nobody. Nobody exists, but isn't anyone.


> Is there a way to understand why Debian is configured so by default?
> Are there official developers that browse this list that could give
> insight to maybe a security reason or any other as to why we have
> these 'orphaned' accounts in a fresh / new minimal install?

Mainly because there's so many things that CAN use these users. Not
every service gets run as root, nor should it.

> Thanks!
> 
> Many of you would just say, "...just remove what you do want" however
> in my opinion, the last thing someone needs to do after installing a
> fresh system is start removing stuff.


Users in *nix and friends are a way to seperate out who can touch what.
This is a security thing, and something that isn't really all that new
or unique to a Debian box. Here's a fresh Fedora install:

root:x:0:0:root:/root:/bin/zsh
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/bin/sh
man:x:6:12:man:/var/cache/man:/bin/sh
lp:x:7:7:lp:/var/spool/lpd:/bin/sh
mail:x:8:8:mail:/var/mail:/bin/sh
www-data:x:33:33:www-data:/var/www:/bin/sh
nobody:x:65534:65534:nobody:/nonexistent:/bin/sh
indrora:x:1000:1000:Morgan Gangwere,,,:/home/indrora:/bin/zsh
sshd:x:104:65534::/var/run/sshd:/usr/sbin/nologin

*nix and its friends use LOTS of users to do LOTS of things. I make
users on a regular basis when I do something that should be chroot'd or
otherwise kept in check.

-- 

Morgan Gangwere

PGP Key at http://indrora.homelinux.org/gpg_key.asc

>> Why?
> Because it breaks the logical flow of conversation, plus makes
messages unreadable.
>>> Top-Posting is evil.

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