[Lilug] ubuntu guest user

[odinson]

One of the reasons we don't recommend Ubuntu for University users despite 
it's popularity.  RHEL, and Fedora if it's bleeding edge.

On personal gear Ubuntu makes more sense.

Matt

On Thu, 3 Nov 2016, Jorg Kewisch wrote:

>
>
> I think this is the 4th time the way to disable the Ubuntu guest user
> changed:
> first one had to add "allow-guest=false" to a file in /etc/lightdm
> then that file moved to /usr/share/lightdm/lightdm.conf.d/50-no-guest.conf
> then the format changed to "[SeatDefaults]\nallow-guest=false\n"
> now the file name is "50-ubuntu.conf"
>
> I have a script that I run after every new install and with each change
> this creepy guest user comes back. I am now convinced that this is
> intentional (paid for by NSA?) and the guest user is a serious security
> hole.
>
> Remember when they found an unapproved change in the Linux kernel a few
> years back?  Some error handler contained :"if( uid = 0) {..}" instead
> of  "if( uid == 0) {..}". Triggering this error would make you root. But
> you can only do that if you are already logged into the computer and
> that is what the guest user is for.This bug was fixed, but there may be
> others.
>
>
> The method de jour to get rid of the guest user is:
> sudo sh -c 'printf "[SeatDefaults]\nallow-guest=false\n" >>
> /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf'
>
>
> jorg
>
>
> P.S. I wrote this message in July, and when I am pissed off I don't send
> it immediately and then forgot about it. Now it happened ***AGAIN***.
> There was an update for lightdm and the update overwrote the conf file.
> That is no accident.
>
> Where can I tell these guys (in colorful language) that enough is
> enough? Where can I tell other sysadmins that this is going on?
>
> Jorg
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> Lilug at lists.lilug.org
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>


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Matthew Newhall, M.A.Newhall at warcloud.net
A.S. in Computer Science, SUNY Farmingdale
President and founder of LILUG;  president at lilug.org, http://www.lilug.org
My theory; Psychopaths precede the conscience, http://civgene.matthewnewhall.com
My maker blog; "The modness", http://themodness.wordpress.com
Scifi book; "Thicker Than Blood"  http://www.thickerthanbloodthebook.com
Giselle's husband, Sebastian and Maxximus's father.
http://www.warcloud.net/~odinson/us/
Meekness:  Uncommon patience in planning a revenge that is worth while.
 	-- Ambrose Bierce
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