Catman file clobbering vulnerability Solaris 2.x

["Larry W. Cashdollar" <lwc () VAPID DHS ORG>]

                    Solaris 2.7/2.8 catman temp file vulnerability.

                                 Larry W. Cashdollar
                                     Vapid Labs

        
Date Published: 12/18/2000

Advisory ID: 11242000-02

Risk: Low

Title: catman temp file vulnerability.

Class:  insecure temp file handling.

Remotely Exploitable:  no

Locally Exploitable:  Yes

Vulnerability Description:

  Through the use of symlinking temporary files created by /usr/bin/catman
upon execution by root a local user can clobber root owned files.

Vulnerable Packages/Systems: Solaris 2.x Sparc/x86

Solution/Vendor Information/Workaround:

  The vendor is currently working on releasing a patch.  See references
section for Vendor contact information.

Sun BugID: 4392144

Vendor notified on: 11/23/2000


Credits:

  I alerted sun to this issue 11/23/2000 they responded 11/24/2000.  Kudos
to the Sun Engineering group.  This response time should be a model to
other vendors.

Technical Description:

  The catman command creates preformatted versions of the online
manual.  It also creates the windex database for utilities like apropos
and whatis.  The problem lies with catman creating a temporary file in
/tmp, the file has the form of /tmp/sman_pidofcatman.  An attacker can
monitor the process list for the execution of catman and create a symlink
to a root owned file.   catman will upon execution overwrite the contents
of that file.  This is a new bug for catman and is not addressed in the
current patch cluster for Solaris 2.7 Sparc.

Exploit/Concept Code: see attachments.

References:

        Sun Microsystems.
        http://www.sun.com

        Vapid Labs.
        http://vapid.betteros.org
        Email: Larry W. Cashdollar <lwc () vapid betteros org>


DISCLAIMER:

The contents of this advisory are copyright (c) 2000 Larry W. Cashdollar and
may be distributed freely provided that no fee is charged for this
distribution and proper credit is given.


Ver 2.4 11/29/2000

Attachment: catman-race.pl
Description:

Attachment: ctman-race2.pl
Description: