SGI Security Advisory 19961101 - Vulnerabilities in systour and

[agent99 () boytoy csd sgi com (SGI Security Coordinator)]

DISTRIBUTION RESTRICTIONS:     NONE - FOR PUBLIC RELEASE


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______________________________________________________________________________
                Silicon Graphics Inc. Security Advisory

     Title:   Possible Vulnerabilities in systour and OutOfBox
     Title:   Subsystems for IRIX 5.x, 6.0.x, 6.1, 6.2 and 6.3
     Number:  19961101-01-I
     Date:    November 6, 1996
______________________________________________________________________________

Silicon Graphics provides this information freely to the SGI user community
for its consideration, interpretation, implementation and use.   Silicon
Graphics recommends that this information be acted upon as soon as possible.

Silicon Graphics  will  not  be  liable  for any  indirect, special, or
consequential damages arising from the use of, failure to use or improper
use of any of the instructions or information in this Security Advisory.
______________________________________________________________________________


Recently, potential security vulnerabilities in the OutOfBox and systour
subsystems have been advertised in several public forums.   Additionally,
the Australian Computer Emergency Response Team (AUSCERT) released an
advisory (AA-96.08) on this issue.

Silicon Graphics Inc. has investigated the issues and recommends the
following steps for neutralizing exposure.  It is HIGHLY RECOMMENDED
that these measures be implemented on ALL SGI systems running IRIX versions
5.0.x, 5.1.x, 5.2, 5.3, 6.0.x, 6.1, 6.2 and 6.3.  This issue will be
corrected in future releases of IRIX.


- --------------
- --- Impact ---
- --------------

The Silicon Graphics Indigo Magic System Tour and OutOfBox Experience
packages are factory installed on all Silicon Graphics Indy systems.

The Indigo Magic System Tour and OutOfBox Experience packages are not
factory installed with any Silicon Graphics Indigo2 systems however, CDs
with these packages are provided with the systems.

The OutOfBox Experience subsystem is factory installed on all Silicon
Graphics O2 systems.  The System Tour subsystem is not part of the
software provided for the O2 system.

Note that either or both the Indigo Magic System Tour and OutOfBox
Experience subsystems maybe be installed from CD on any Silicon Graphics
system.

The purpose of these two packages, systour and OutOfBox, are to demonstrate
and highlight the features and capabilities of the user environment and
system.

Due to the disk space requirements of these subsystems, most sites will
remove these subsystems for disk space reclamation as part of initial
system setup.  Those sites which have done this will not be vulnerable.

On those systems that the subsystems are still installed on, both
subsystems provide background setuid root programs to perform a subsystem
removal when a user decides to remove the software.  This removal is done
using the standard IRIX /usr/sbin/inst program that manages IRIX software.

Provided with the right environment, the inst program could be manipulated
to execute arbitrary commands with root privileges.

An account on the vulnerable system is required for exploit.  With an
account, these vulnerabilities are exploitable by both local and remote
access.



- ----------------
- --- Solution ---
- ----------------

There are no patches for these issues.   However, using the
information below steps can be taken to eliminate the exposure.

To determine if the OutOfBox and systour subsystems are installed
on a particular system, the following command can be used:


         % versions OutOfBox.sw systour.sw
         I = Installed, R = Removed

           Name                 Date      Description

        I  OutOfBox             11/05/96  OutOfBox Experience, 1.1
        I  OutOfBox.sw          11/05/96  OutOfBox Experience Software, 1.1
        I  OutOfBox.sw.complete 11/05/96  Complete OutOfBox Experience
        I  OutOfBox.sw.intro    11/05/96  OutOfBox Intro Movies

        I  systour              02/12/96  Indigo Magic System Tour, 5.2
        I  systour.sw           02/12/96  System Tour Execution Environment
        I  systour.sw.eoe       02/12/96  System Tour Execution Environment


In the above case, the subsystems of concern are installed and the steps
below should be performed.  If no output is returned by the command,
the subsystems are not installed and no further action is required.



**** IRIX 4.x ****

The 4.x version of IRIX is not vulnerable as the System Tour and
OutOfBox Experience subsystems are not part of available software
for this IRIX version.  No action is required.



**** IRIX 5.x, 6.0, 6.0.1, 6.1, 6.2 ****

There are no patches for this issue.

The steps below can be used to remove the vulnerability by either
changing the program permissions (use step 2a) or by removing the
subsystems (use step 2b).



     1) Become the root user on the system.

                % /bin/su -
                Password:
                #


     2) Choose either step 2a or 2b depending on which
        has the desired result.


     2a) Change the setuid root permissions on the programs
         of concern.


                # /bin/chmod u-s /usr/lib/tour/bin/RemoveSystemTour
                # /bin/chmod u-s /usr/people/tour/oob/bin/oobversions

                           ************
                           *** NOTE ***
                           ************

               Removing the setuid root permissions from these tools
               will prevent non-root users from removing the subsystems.
               Removal of the subsystems will only be possible if the
               systour or OutOfBox user is a root user or if the inst
               IRIX software manager is used by root for removal.



      2b) Remove the vulnerable subsystems.

                # /usr/sbin/versions -v remove systour OutOfBox



     4) Return to previous level.

                # exit
                $





**** IRIX 6.3 ****


The IRIX operating system version 6.3 does not have the System
Tour subsystem but does have the OutOfBox Experience subsystem.

There are no patches for this issue.

The steps below can be used to remove the vulnerability by either
changing the program permissions (use step 2a) or by removing the
subsystems (use step 2b).



     1) Become the root user on the system.

                % /bin/su -
                Password:
                #


     2) Choose either step 2a or 2b depending on which
        has the desired result.

     2a) Change the setuid root permissions on the program
         of concern.


                # /bin/chmod u-s /usr/people/tour/oob/bin/oobversions

                           ************
                           *** NOTE ***
                           ************


               Removing the setuid root permissions from this program
               will prevent non-root users from removing the subsystem.
               Removal of the subsystem will only be possible if the
               OutOfBox user is a root user or if the inst IRIX software
               manager is used by root for removal.



      2b) Remove the vulnerable subsystem.

                # /usr/sbin/versions -v remove OutOfBox



     4) Return to previous level.

                # exit
                $





- ------------------------
- --- Acknowledgments ---
- ------------------------

Silicon Graphics wishes to thank AUSCERT and FIRST members worldwide for
their assistance in this matter.



- -----------------------------------------
- --- SGI Security Information/Contacts ---
- -----------------------------------------

If there are questions about this document, email can be sent to
cse-security-alert () csd sgi com.

                      ------oOo------

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                      ------oOo------

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                      ------oOo------

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