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________________________________________________________________________________
                Silicon Graphics Inc. Security Advisory

        Title: IRIX 5.2, 6.0, 6.0.1 Desktop Permissions Tool
                Number:         19950301-01-P373
                Date:           March 3, 1995
________________________________________________________________________________

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

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


A vulnerability has been discovered in the IRIX 5.2, 6.0, and 6.0.1 operating
systems regarding the permissions tool under the IRIX desktop environment.
Normally, this tool is used by users to modify the permissions on their files 
and files they are privileged for.  Under certain conditions, a user may be 
able to modify the permissions for any file.  This is identified as SGI
SCR # 265071.

SGI Engineering has investigated this issue and recommends the following 
steps for neutralizing the exposure.  It is HIGHLY RECOMMENDED that these 
measures be done on ALL SGI systems running IRIX 5.2, 6.0, and 6.0.1 .
This issue is corrected in 5.3 of IRIX and will be corrected in future 
releases of IRIX.

- --------------------------
- --- Immediate Solution ---
- --------------------------
        
The most immediate solution for this issue is to remove the setuid/setgid 
bits on /usr/lib/permissions, or to remove the tool entirely.  Removing the 
setuid/setgid bits will limit the tool to only function on files owned by 
the user using the tool.

        1) Become the root user on the system.

                % /bin/su -
                Password:
                #

        2) Change the unix permissions level on the desktop
  permissions program.


                # chmod u-s /usr/lib/desktop/permissions
    # chmod g-s /usr/lib/desktop/permissions

        3) Return to previous user.

                # exit
                %



- --------------------------
- --- Long Term Solution ---
- --------------------------

*** IRIX 5.0.x, 5.1.x ****

The versions 5.0.x and 5.1.x of IRIX were limited hardware, specific 
releases and have since been obsoleted by later versions of IRIX.  For 
supportability reasons, upgrading to atleast IRIX 5.2 is recommended
as a first step for all problem resolution.   IRIX 5.0.x, 5.1.x ARE
NOT subject to this vulernability.



**** IRIX 5.2, 6.0, 6.0.1 ****

  >>>> IRIX 5.3 IS NOT SUBJECT TO THIS VULNERABILITY. <<<<

For the IRIX operating system versions 5.2, 6.0 and 6.0.1, an inst-able 
patch has been generated and made available via anonymous ftp and/or your 
service/support provider.  The patch is number 373 and will install on 
IRIX 5.2, 6.0 and 6.0.1 .  

- -NOTE- Inst-able patches require a patch-aware inst program.  The stock 
5.2 inst program with the base install is not patch-aware.  The 6.0
and 6.0.1 inst programs are.  A patch-aware inst program for IRIX 5.2 is 
available as patch number 0, 34, or 84.  Any one of these may be used, with 
84 the latest, most recommended, and available via your service provider
or the usual SGI anonymous ftp sites.

The SGI anonymous ftp site is ftp.sgi.com (192.48.153.1).  Additionally,
the alternative SGI anonymous ftp site, sgigate.sgi.com,  can be accessed
to find the same files.  On each of these servers, patch 373 can be found 
in the following directories:

        ~ftp/Security

                or

        ~ftp/Patches/5.2
        ~ftp/Patches/6.0
        ~ftp/Patches/6.0.1

                        ##### Checksums ####

The actual patch will be a tar file containing the following files:

Filename:                 patchSG0000373
Algorithm #1 (sum -r):    51249 1 patchSG0000373
Algorithm #2 (sum):       21641 1 patchSG0000373
MD5 checksum:             40A604013A05C2521152ED4B51C5D9A5

Filename:                 patchSG0000373.desktop_eoe_sw
Algorithm #1 (sum -r):    09134 88 patchSG0000373.desktop_eoe_sw
Algorithm #2 (sum):       63013 88 patchSG0000373.desktop_eoe_sw
MD5 checksum:             D74F9BDED3D51E9D28666CADF1B31945

Filename:                 patchSG0000373.idb
Algorithm #1 (sum -r):    50435 1 patchSG0000373.idb
Algorithm #2 (sum):       41363 1 patchSG0000373.idb
MD5 checksum:             790E9A47909BC32D8E9FCE14EA4077D8





- ------------------------------------
- --- Further Information/Contacts ---
- ------------------------------------

For obtaining security information, patches or assistance, please
contact your SGI support provider.

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

For reporting *NEW* SGI security issues, email can be sent to
security-alert@sgi.com .



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