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===========================================================================
              AUSCERT External Security Bulletin Redistribution

                             
              ESB-98.139 -- SGI Security Advisory 19980803-01-I
                        Seyon Security Vulnerability
                               28 August 1998

===========================================================================

Silicon Graphics Inc. has released the following advisory concerning a
vulnerability in the serial port communications package (Seyon) for X
windows.  This vulnerability may allow local and remote users with a valid
account on the system to gain root access.

This vulnerability has been actively exploited on IRIX systems.


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______________________________________________________________________________
                Silicon Graphics Inc. Security Advisory

        Title:   Seyon Security Vulnerability
        Number:  19980803-01-I
        Date:    August 27, 1998
______________________________________________________________________________

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
Silicon Graphics 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.
______________________________________________________________________________


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

seyon is a serial port communications package for X windows.

A vulnerability has been discovered in the seyon program which can lead to
a root compromise. Any user who can execute the seyon program can exploit
this vulnerability. This vulnerability is being actively exploited.

Silicon Graphics, Inc. has investigated the issue and recommends that IRIX
system administrators take appropriate steps according to their local site
security policies and requirements.

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

Silicon Graphics distributes the Seyon package as an IRIX inst image called
"fw_MSSeyon" on the SGI Freeware 1.0 and 2.0 CDROMs.

The "fw_MSSeyon" IRIX inst images are also available on the web at the
following SGI Freeware sites:

        http://freeware.sgi.com/
        http://toolbox.sgi.com/TasteOfDT/public/

IRIX customers who have installed "fw_MSSeyon" IRIX inst images from any
source prior to and including v2.14c are vulnerable.

A local account is required on the vulnerable system in order to exploit
this issue locally and remotely.

seyon is set-uid program and when exploited, can lead to a root compromise.

This vulnerability has been publicly discussed in Usenet newsgroups
and mailing lists.

This vulnerability is being actively exploited on IRIX systems.


- - --------------------------
- - --- Temporary Solution ---
- - --------------------------

There are two temporary solutions available for this security issue.

        I)  Remove the vulnerable seyon package.
        II) Remove the set-uid bit of the seyon program.

SGI recommends that IRIX system administrators take appropriate steps
according to their local site security policies and requirements.

I) To remove the vulnerable Seyon package use the following steps.

     1) Check to see if the vulnerable subsystem is installed.
        Version 2.14c of fw_MSSeyon is vulnerable.

        % versions -b fw_MSSeyon
           Name           Date      Description
        I  fw_MSSeyon     08/26/97  Seyon X Telecommunications Package version
                                    2.14c by Muhammad M. Saggaf

     2) Become the root user on the system.

        % /bin/su -
        Password:
        #


     3) Remove the vulnerable subsystem.

        # versions remove fw_MSSeyon


     4) Return to previous level.

        # exit
        %


II) To remove the set-uid bit of the seyon program use the following steps.

     1) Check to see if the vulnerable subsystem is installed.
        Version 2.14c of fw_MSSeyon is vulnerable.

        % versions -b fw_MSSeyon
           Name           Date      Description
        I  fw_MSSeyon     08/26/97  Seyon X Telecommunications Package version
                                    2.14c by Muhammad M. Saggaf

     2) Become the root user on the system.

        % /bin/su -
        Password:
        #


     3) Remove the set-uid bit.

        # /usr/bin/chmod u-s /usr/freeware/bin/seyon


     4) Verify the new permissions on the program.
        Note that the program size may be different depending on release.

        # ls -al /usr/freeware/bin/seyon
        -rwxr-xr-x   1 root sys  181600 Aug 26 1997 /usr/freeware/bin/seyon

     5) Return to previous level.

        # exit
        %


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

Silicon Graphics does not distribute patches for SGI Freeware software.

At this time, an update or patch is not available from the author of
Seyon nor at the main distribution site:

        ftp://sipb.mit.edu/pub/seyon/notice.sipb

If the author of Seyon provides an update or patch, future release of
SGI Freeware will attempt to include the update or patch.

Future releases of SGI Freeware software will be hosted at:

        http://freeware.sgi.com/


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

Silicon Graphics wishes to thank the NCSA and other FIRST Organization
(http://www.first.org/) members for their assistance in this matter.


- - -----------------------------------------------------------
- - --- Silicon Graphics Inc. Security Information/Contacts ---
- - -----------------------------------------------------------

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

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

Silicon Graphics 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 information and patches
is sgigate.sgi.com (204.94.209.1).  Security information and patches
are located under the directories ~ftp/security and ~ftp/patches,
respectively. The Silicon Graphics Security Headquarters Web page is
accessible at the URL http://www.sgi.com/Support/security/security.html.

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

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

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

Silicon Graphics 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 list can be done via the Web
(http://www.sgi.com/Support/security/wiretap.html) or by sending email
to SGI as outlined below.

% mail wiretap-request@sgi.com
subscribe wiretap <YourEmailAddress>
end
^d

In the example above, <YourEmailAddress> is the email address that you
wish the mailing list information sent to.  The word end must be on a
separate 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------

Silicon Graphics provides a comprehensive customer World Wide Web site.
This site is located at http://www.sgi.com/Support/security/security.html.

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

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, Silicon
  Graphics is appropriately credited and the document retains and
  includes its valid PGP signature.


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