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Re: [LUG] Secure Shell?

 

On Tue, 12 Jul 2011 19:45:04 +0100
Simon Waters wrote:

> On 12/07/11 17:57, Grant Sewell wrote:
> > On Tue, 12 Jul 2011 14:12:49 +0100
> > Kevin Lucas wrote:
> > 
> >> Just been reading the LinuxUser mag and tried this from Joanna
> >> Rutkowska It shows how insecure a root shell can be
> 
> s/root shell/X11/
> 
> >  or just Never install the Xorg-X11-apps
> 
> The bad guys will install their own apps that do the same thing, Xkey
> has been around since at least 2004 (probably earlier) which uses the
> same library calls to find the keyboard device and record key events.
> 
> > Not a good situation to be in, but not one I imagine that will cause
> > that many problems in current systems.  Either that or I'm being
> > short-sighted about this.
> 
> May be.
> 
> > It would seem that "xinput --test xx" will only show the input for
> > the current X session.  My keyboard shows up as id 11.  I just
> > tried running "xinput --test 11" in one window, opened another
> > Gnome Terminal window and sure enough, the xinput test picked up
> > the keypresses from the new terminal window, including after I had
> > sudo su'd.  Not good... but... I then tried running "xinput --test
> > 11", swapped to another virtual terminal (CTRL+ALT+F1), logged in,
> > ran a few commands and swapped back to the X session... none of the
> > keypresses from the "other" session were picked up.  Not surprising
> > as the "other" session didn't involve X.
> 
> Yeap.
> 
> > I can see some potential situations where this would be a potential
> > problem, but then to my mind those situations would only arise if
> > the system has been poorly setup anyway.
> 
> It is a design flaw in X, the design assumption was that anything
> running as the local user can do anything to the current session.
> 
> X also has other flaws... from the Open BSD page at Wikipedia
> 
> =========================
> Theo de Raadt commented that the aperture driver was merely "the best
> we can do" and that X "violates all the security models you will hear
> of in a university class."[14] He went on to castigate X developers
> for "taking their time at solving this > 10 year old problem."
> Recently, a VESA kernel driver has been developed, which permits X to
> run, albeit more slowly, without the use of the aperture driver[1].
> =========================
> 
> Those who think GNU/Linux is a secure operating system have had their
> judgement corrupted by vendors who ship operating systems that are
> even less secure.

In all honesty, there is no such thing as a "secure operating system" -
there are only levels of insecurity.

Grant.

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