IRIX fsr_xfs vulnerability

[SGI Security Coordinator <agent99 () sgi com>]

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_____________________________________________________________________________

                          SGI Security Advisory

        Title:      fsr_xfs vulnerability
        Number:     20020504-01-I
        Date:       May 8, 2002
        Reference:  CAN-2002-0356
_____________________________________________________________________________

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

It's been reported that there is a problem with the fsr_xfs (XFS filesystem
reorganizer) program that can, under certain circumstances, be manipulated
by someone with malicious intent into causing critical system files to be
overwritten.  This could potentially lead to a root exploit.

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


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

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

  # uname -R

That will return a result similar to the following:

    # 6.5 6.5.15f

The first number ("6.5") is the release name, the second ("6.5.15f" in this
case) is the extended release name.  The extended release name is the
"version" we refer to throughout this document.

The fsr_xfs binary is installed by default on IRIX 6.5 systems as part of
eoe.sw.base.

These vulnerabilities may not be exploited by a remote user, a local account
is required.  This vulnerability can lead to a root exploit.

This vulnerability has been fixed in IRIX 6.5.11 and later versions of IRIX.

This vulnerability was assigned the following CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-0356


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

As a temporary workaround until you can upgrade the operating system to
6.5.11 or later, you can change root's crontab to run fsr_xfs with the -f
option and point at a directory that normal users can't write to, such as
/var/adm.

To set up this workaround, follow these steps:

1) Become the superuser

   $ su -

2) Use vi or your favorite text editor to edit the file
/var/spool/cron/crontabs/root

   # vi /var/spool/cron/crontabs/root

3) Look for a line that looks like this:

   0       3       *       *       0       if test -x /usr/etc/fsr; then (cd
/usr/tmp; /usr/etc/fsr) fi

4) Change it to this:

   0       3       *       *       0       if test -x /usr/etc/fsr; then (cd
/usr/tmp; /usr/etc/fsr -f /var/adm/.fsrlast) fi

5) Save the file and exit from the editor.  crond will automatically detect
the changes to the file, so it is not necessary to stop and restart crond.

However, SGI recommends upgrading to at least IRIX 6.5.11, with later
versions being preferred.


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

SGI has not provided patches for this vulnerability. Our
recommendation is to upgrade to IRIX 6.5.11 or a later version of IRIX.

   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       no
   IRIX 6.5.12       no
   IRIX 6.5.13       no
   IRIX 6.5.14       no
   IRIX 6.5.15       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 6.5.11 or a later version of IRIX.


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

SGI wishes to thank John Vanderpool, 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
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______________________________________________________________________________
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