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

                             
              ESB-98.126 -- SGI Security Advisory 19950123-02-I 
	         IRIX IP Spoofing/TCP Sequence Attack Update
                               07 August 1998

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

Silicon Graphics Inc. has released the following updated advisory
concerning the ISS System Security Scanner (S3) v1.5 for IRIX.


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______________________________________________________________________________
                Silicon Graphics Inc. Security Advisory

        Title:   IRIX IP Spoofing/TCP Sequence Attack Update
        Title:   CERT CA-96:21 supersedes CERT CA-95:01
        Title:   SGI Advisory 19961202-01-PX
        Number:  19950123-02-I
        Date:    August 6, 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 ---
- - ------------------------

Due to the recent confusion generated by the Internet Security Systems' (ISS)
System Security Scanner (S3) Tool v1.5 on IRIX, an update to this advisory
has been generated.

When CERT CA-95.01 (IP Spoofing Attacks and Hijacked Terminal Connections)
was released, SGI released an acknowledgment advisory 19950123-01-A during
the investigation.

Later, CERT CA-96.21 (TCP SYN Flooding and IP Spoofing Attacks) was released
which superseded the IP spoofing portion of CA-95.01. At that time, SGI
responded with 19961202-01-PX security advisory which referenced patches
for TCP SYN, "Ping of Death" and TCP Sequence/IP Spoof Attack.

Unfortunately, when the ISS S3 Tool is scanning IRIX for the TCP Sequence/IP
Spoof Attack vulnerability, it incorrectly references SGI Advisory
19950123-01-A.

The correct SGI Advisory for TCP Sequence/IP Spoof Attack is 19961202-01-PX.

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.  This
issue will be corrected in future releases of IRIX.


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

The ISS System Security Scanner (S3) v1.5 for IRIX can be installed from
the optional WebFORCE Feb. 1998 CD or can be purchased from ISS at:
http://www.iss.net/

IRIX 5.3 and IRIX 6.2 are vulnerable to TCP Sequence/IP Spoof Attacks.

A local account is not need in order to exploit these vulnerabilities.

These vulnerabilities have been publically discussed in Usenet newsgroups
and mailing lists.


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

Please see SGI Advisory 19961202-01-PX for patch information:
ftp://sgigate.sgi.com/security/19961202-01-PX


   OS Version     Vulnerable?     Patch #      Other Actions
   ----------     -----------     ---------    -------------

   IRIX 3.x          yes          not avail    Note 1
   IRIX 4.x          yes          not avail    Note 1
   IRIX 5.0.x        yes          not avail    Note 1
   IRIX 5.1.x        yes          not avail    Note 1
   IRIX 5.2          yes          not avail    Note 1
   IRIX 5.3          yes           1529
   IRIX 6.0.x        yes          not avail    Note 1
   IRIX 6.1          yes          not avail    Note 1
   IRIX 6.2          yes           1418
   IRIX 6.3          no
   IRIX 6.4          no
   IRIX 6.5          no

   NOTES

     1) Upgrade to currently supported IRIX operating system.


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

Silicon Graphics wishes to thank the CERT Coordination Center 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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