OSEC

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Subject: Re: Solaris patchadd(1) (3) symlink vulnerabilty
From: Juergen P. Meier (jpmCLASS.DE)
Date: Thu Dec 21 2000 - 05:09:31 CST

On Thu, Dec 21, 2000 at 09:13:29AM +1100, Paul Szabo wrote:
> Juergen P. Meier <jpmclass.de> wrote:
>
> > Solaris /usr/sbin/patchadd is a /bin/ksh script.
> > The problem lies in the vulnerability of ksh.
>
> Damn: thus it would seem that not only sh, but also ksh is vulnerable!

seems so :(

> > However: Sun Microsystems does recommend to only install
> > patches at single-user mode (runlevel S). ...
> > ... if you follow the Vendors recommendations, you are
> > not vulnerable.
>
> The attacker can create the symlinks before you go single-user. As the
> original poster Jonathan Fortin <jfortinREVELEX.COM> said:
>
> > Only solution is to rm -rf /tmp/* /tmp/.* [and] make sure no users are on
>
> Paul Szabo - pszmaths.usyd.edu.au http://www.maths.usyd.edu.au:8000/u/psz/
> School of Mathematics and Statistics University of Sydney 2006 Australia

I do indeed stand corrected: The only 2 sollutions are:
1) change to single user mode by means of init S
   and rm -rf /tmp/* /tmp/.*
2) shutdown and boot -s into single user mode.

you should do this at least once (when sun releases the shell-patches ;)

have a nice day,

Juergen 

--
Juergen P. Meier                        email: jpmclass.de