SGI Security Advisory 19970301-01-P - IRIX 5.x and 6.x fsdump

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______________________________________________________________________________
                Silicon Graphics Inc. Security Advisory

        Title:   IRIX 5.x and 6.x fsdump Security
        Number:  19970301-01-P
        Date:    March 10, 1997
______________________________________________________________________________

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 provides the information in this Security Advisory on
an "AS-IS" basis only, and disclaims all warranties with respect thereto,
express, implied or otherwise, including, without limitation, any warranty
of merchantability or fitness for a particular purpose.  In no event shall
SGI be liable for any loss of profits, loss of business, loss of data or
for any indirect, special, exemplary, incidental or consequential damages
of any kind arising from your use of, failure to use or improper use of
any of the instructions or information in this Security Advisory.
______________________________________________________________________________

- -------------------
- --- Description ---
- -------------------

A security vulnerability has been found with the fsdump program
used in the rfind Server Utilities, in the optionally installed
subsystem eoe.sw.rfindd (IRIX 6.2) or eoe2.sw.rfindd (IRIX
releases prior to 6.2).

Silicon Graphics Inc. 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 running
IRIX versions 5.x, 6.0.x, 6.1, and 6.2.  This issue has been corrected in
more recent releases of IRIX and will be corrected in future releases
of IRIX.



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

The fsdump program is found in the eoe.sw.rfindd and eoe2.sw.rfindd
subsystems which are not installed by default.   As optional subsystems,
these packages must be explicitly installed for use.   Only systems with
the fsdump program present are vulnerable.

Root permissions can be obtained on any system which has the
/var/rfindd/fsdump program installed with setuid permissions.

Exploitation of this vulnerability requires access to an established
account on the system.

Provided with an established account, the vulnerability can be exploited
locally or remotely.

This issue has been publically disclosed in several public forums
including the BUGTRAQ mailing list.


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

The solution to this problem is to remove the setuid bit on the
fsdump program or to remove the rfindd subsystem.

To determine if the subsystem containing the fsdump program is installed
on a particular system, the following command can be used:

   % versions -Inv | grep rfindd

   I  eoe.sw.rfindd        1233007732  rfind Server Utilities


In the above case, the optional subsystem containing the fsdump software is
installed and the steps in the section titled "**** IRIX 5.x, 6.0, 6.0.1,
6.1, 6.2 ****" should be performed.  If no output is returned then the
subsystem is not installed but existence of the program should be
double checked with the following command:

   % ls -al /var/rfindd/fsdump /usr/rfindd/fsdump
   Cannot access /var/rfindd/fsdump: No such file or directory
   Cannot access /usr/rfindd/fsdump: No such file or directory


In the above case, the fsdump program is not found and no further action
is required.   If a file listing is returned, then the fsdump program is
present and the steps below should be performed.




**** 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.  There
are two possible solutions to this issue.  Solution A in which
the fsdump program permissions are corrected or Solution B in
which the rfindd subsystem is removed.  Either solution can be
used depending on site requirements.





Solution A - Change program permissions.


     1) Become the root user on the system.

                % /bin/su -
                Password:
                #


     2) Move fsdump's cron task from the rfindd crontab file
        (/var/spool/cron/crontabs/rfindd) to the crontab file
        for root (/var/spool/cron/crontabs/root) by concatenating
        the rfind crontab file to the root crontab file.  Then
        move the rfindd crontab file out of the way so it will not
        be used.

                # cd /var/spool/cron/crontabs
                # cat rfindd >> root
                # mv rfindd rfindd.old.insecure


     3) Edit the root crontab file and change the newly added line to
        execute in the rfindd directory.

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

        {Find the newly added fsdump line}

            3 0-3,5-23 * * * /etc/chkconfig rfindd && exec ./runfsdump

        {Add the cd operation to the fsdump line}

          New entry ----+
                        |
                        V
                   |-------------|
  3 0-3,5-23 * * * cd /var/rfindd; /etc/chkconfig rfindd && exec ./runfsdump

        {Save the file and exit}



     4) Remove the setuid bit from the shipped fsdump program

            # chmod -s /var/rfindd/fsdump


     5) Return to previous level.

                # exit
                $



Solution B - Removal of the software.


     1) Become the root user on the system.

                % /bin/su -
                Password:
                #


     2) Remove the vulnerable subsystems.

                # /usr/sbin/versions -v remove eoe.sw.rfindd eoe2.sw.rfindd


     3) Determine what patches are install on the system.

                # versions -b | grep patch | cut -c4-20


     4) From the patches found in step 3, remove any occurances of
        the following patches:


                 patchSG0000159
                 patchSG0000415
                 patchSG0000528
                 patchSG0000739
                 patchSG0000852
                 patchSG0000159
                 patchSG0001122

        To remove a patch, use the versions command.  For example,
        to remove the patch patchSG0000528:


                # /usr/sbin/versions -v remove patchSG0000528


     5) Return to previous level.

                # exit
                $





**** IRIX 6.3 and 6.4 ****


The IRIX operating system versions 6.3 and 6.4 do not have this
vulnerability and no further action is required.






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



Silicon Graphics wishes to thank 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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______________________________________________________________________________
  This information is provided freely to all interested parties and may
  be redistributed provided that it is not altered in any way, Silicon
  Graphics is appropriately credited and the document retains and
  includes its valid PGP signature.


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