Date: Wed, 26 Mar 2008 08:21:49 +0100
From: Lubomir Kundrak <lkundrak@...hat.com>
To: oss-security@...ts.openwall.com
Subject: Re: was: SA29489 CenterIM URL handling flaw


On Tue, 2008-03-25 at 16:26 +0100, Nico Golde wrote:
> Hi,
> * Nico Golde <oss-security+ml@...lde.de> [2008-03-25 16:25]:
> > * Lubomir Kundrak <lkundrak@...hat.com> [2008-03-24 15:08]:
> > > Ad SA29489 [1] "CenterIM URL Parsing Command Execution Vulnerability"
> > > 
> > > CenterIM does completely nothing with received URLs. Maybe the
> > > unfortuate "exploit writer" was using XFCE Terminal [2], or a terminal
> > > emulator with a similar problem.
> > 
> > That's partly true. While centerim has no special URL 
> > handler to handle incoming urls it does provide the ability 
> > to list urls in a message by pressing F2. If you press enter 
> > on one of these urls it tries to open it in an external 
> > browser and executes the other commands as well.
> > 
> > You see the commands in the URL however so I think the 
> > impact of this is like sending someone a message with 
> > "please type rm -rf ~ in your shell" so the secunia rating 
> > is a bit beyond the actual impact.
> 
> upstream patch:
> http://repo.or.cz/w/centerim.git?a=blobdiff_plain;f=src/icqconf.cc;fp=src/icqconf.cc;hb=b28c6deaef58eb685a2d747b28b6a572122730d4;hpb=ad6ad53ebf791f97cb7337dc79ab2ce8ccb1246f

The patch doesn't apply by itself, without the previous one, and is not
quite correct. If the user created a vulnerable actions file (by
launching centerim before), that one won't be overwritten without manual
action taken by the user.

Also, the script is not technically correct (overriding DISPLAY
variable), and is completely useless bloat. Upstream is aware of this
and concentrates on making CIM5 better :)

Fedora will use this patch [1], that removes configurable actions
completely.

[1] http://cvs.fedora.redhat.com/viewcvs/rpms/centerim/devel/centerim-4.22.3-url-escape-fedora.patch?rev=1.1&view=markup

Note that current Yahoo IM implementation will not work after April 2nd,
and new one is not yet complete. It might make sense to delay the update
a few days and grab the YIM patches from mob branch then.

Regards,
-- 
Lubomir Kundrak (Red Hat Security Response Team)

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