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_____________________________________________________________________________

                          SGI Security Advisory

        Title:      IRIX default root umask and coredumps
        Number:     20020902-01-I
        Date:       September 18, 2002
_____________________________________________________________________________

- -----------------------
- --- Issue Specifics ---
- -----------------------

IRIX 6.5's umask setting is applied to system coredumps.  While that
is not a bug, it is a design decision that has consequences for the
security of an IRIX system.

Since the default umask for the root user is 022, root's coredumps are
created with permissions of "-rw-r--r--". That means unprivileged users can
read them. Coredumps can potentially contain sensitive information, and this
could be used to compromise system security.

SGI has investigated the issue and recommends the following steps for 
neutralizing the exposure.  It is HIGHLY RECOMMENDED that these measures be
implemented on ALL vulnerable SGI systems. 


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

The "022" root umask is configured by default on IRIX 6.5 systems.

To determine the version of IRIX you are running, execute the following
command: 

  # /bin/uname -R
  
That will return a result similar to the following:

  # 6.5 6.5.16f
  
The first number ("6.5") is the release name, the second ("6.5.16f" in this
case) is the extended release name.  The extended release name is the
"version" we refer to throughout this document.  

To see what root's umask is currently set to, execute the following commands:

   $ su -
   # umask
   
If the system returns "022" and the IRIX version is earlier than 6.5.15,
then the system may be vulnerable.


- ----------------------------
- --- Temporary Workaround ---
- ----------------------------

SGI understands that there are times when upgrading the operating system or
installing patches are inconvenient or not possible.  In those instances, we
recommend the following workaround:

Change the root user's umask to something that will not allow unprivileged
users to read files created by root:

   $ su -
   # umask 077
   
or add "umask 077" to /etc/profile or the global configuration files
corresponding to what shell root uses.
   
There can be negative side effects to this, however, as it may be necessary
for users to be able to read some files created by root, and in those cases
root would have to manually chmod the files to the appropriate permissions.   

SGI recommends upgrading to IRIX 6.5.15 or later, where SGI has introduced a
new systune variable called "coremask".  Using systune to tune the value of
coremask to an appropriate value for corefiles will allow root to have a
value separate from root's umask to control the permissions of core files.

Setting the coremask variable is documented in /var/sysgen/mtune/kernel
on IRIX 6.5.15 and later systems.


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

Please update to IRIX 6.5.15 if you would like to implement this new
functionality.


   OS Version     Vulnerable?     Patch #      Other Actions
   ----------     -----------     -------      -------------    
   IRIX 3.x        unknown                     Note 1
   IRIX 4.x        unknown                     Note 1
   IRIX 5.x        unknown                     Note 1
   IRIX 6.0.x      unknown                     Note 1          
   IRIX 6.1        unknown                     Note 1         
   IRIX 6.2        unknown                     Note 1
   IRIX 6.3        unknown                     Note 1
   IRIX 6.4        unknown                     Note 1
   IRIX 6.5          yes                       Notes 2 & 3
   IRIX 6.5.1        yes                       Notes 2 & 3
   IRIX 6.5.2        yes                       Notes 2 & 3
   IRIX 6.5.3        yes                       Notes 2 & 3
   IRIX 6.5.4        yes                       Notes 2 & 3
   IRIX 6.5.5        yes                       Notes 2 & 3
   IRIX 6.5.6        yes                       Notes 2 & 3
   IRIX 6.5.7        yes                       Notes 2 & 3
   IRIX 6.5.8        yes                       Notes 2 & 3
   IRIX 6.5.9        yes                       Notes 2 & 3
   IRIX 6.5.10       yes                       Notes 2 & 3
   IRIX 6.5.11       yes
   IRIX 6.5.12       yes
   IRIX 6.5.13       yes
   IRIX 6.5.14       yes
   IRIX 6.5.15       no
   IRIX 6.5.16       no
   IRIX 6.5.17       no
   
   NOTES
 
     1) This version of the IRIX operating has been retired. Upgrade to an
        actively supported IRIX operating system.  See
        http://support.sgi.com/irix/news/index.html#policy for more
        information.

     2) If you have not received an IRIX 6.5.X CD for IRIX 6.5, contact your 
        SGI Support Provider or URL: http://support.sgi.com/irix/swupdates/

     3) Upgrade to IRIX 6.5.15 or later. See the following website:
        http://support.sgi.com/colls/patches/tools/relstream/index.html


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

SGI wishes to thank FIRST and the users of the Internet Community at large
for their assistance in this matter.


- -------------
- --- Links ---
- -------------

SGI Security Advisories can be found at:
http://www.sgi.com/support/security/ and
ftp://patches.sgi.com/support/free/security/advisories/

SGI Security Patches can be found at:
http://www.sgi.com/support/security/ and 
ftp://patches.sgi.com/support/free/security/patches/

SGI patches for IRIX can be found at the following patch servers:
http://support.sgi.com/irix/ and ftp://patches.sgi.com/

SGI freeware updates for IRIX can be found at:
http://freeware.sgi.com/

SGI fixes for SGI open sourced code can be found on:
http://oss.sgi.com/projects/

SGI patches and RPMs for Linux can be found at:
http://support.sgi.com/linux/ or 
http://oss.sgi.com/projects/sgilinux-combined/download/security-fixes/

SGI patches for Windows NT or 2000 can be found at:
http://support.sgi.com/nt/

IRIX 5.2-6.4 Recommended/Required Patch Sets can be found at:
http://support.sgi.com/irix/ and ftp://patches.sgi.com/support/patchset/

IRIX 6.5 Maintenance Release Streams can be found at:
http://support.sgi.com/colls/patches/tools/relstream/index.html

IRIX 6.5 Software Update CDs can be obtained from:
http://support.sgi.com/irix/swupdates/

The primary SGI anonymous FTP site for security advisories and patches is
patches.sgi.com (216.32.174.211).  Security advisories and patches are
located under the URL ftp://patches.sgi.com/support/free/security/

For security and patch management reasons, ftp.sgi.com (mirrors
patches.sgi.com security FTP repository) lags behind and does not do a
real-time update.


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

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

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

SGI provides security information and patches for use by the entire SGI 
community.  This information is freely available to any person needing the
information and is available via anonymous FTP and the Web. 

The primary SGI anonymous FTP site for security advisories and patches is
patches.sgi.com (216.32.174.211).  Security advisories and patches are
located under the URL ftp://patches.sgi.com/support/free/security/

The SGI Security Headquarters Web page is accessible at the URL:
http://www.sgi.com/support/security/

For issues with the patches on the FTP sites, email can be sent to 
security-info@sgi.com.

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

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

SGI provides a free security mailing list service called wiretap and 
encourages interested parties to self-subscribe to receive (via email) all 
SGI Security Advisories when they are released. Subscribing to the mailing 
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(http://www.sgi.com/support/security/wiretap.html) or by sending email to
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subscribe wiretap <YourEmailAddress such as aaanalyst@sgi.com > 
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In the example above, <YourEmailAddress> is the email address that you wish
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line to indicate the end of the body of the message. The control-d (^d) is
used to indicate to the mail program that you are finished composing the
mail message.


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

SGI provides a comprehensive customer World Wide Web site. This site is 
located at http://www.sgi.com/support/security/ .

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

If there are general security questions on SGI systems, email can be sent to
security-info@sgi.com.

For reporting *NEW* SGI security issues, email can be sent to
security-alert@sgi.com or contact your SGI support provider.  A support
contract is not required for submitting a security report.

______________________________________________________________________________
      This information is provided freely to all interested parties 
      and may be redistributed provided that it is not altered in any 
      way, SGI is appropriately credited and the document retains and 
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