AUSCERT External Security Bulletin Redistribution
            ESB-98.081 -- SGI Security Advisory 19980503-01-I
                tcpmux Port Scanning and Root Compromises
                              29 May 1998


Silicon Graphics Inc. has released the following advisory concerning
tcpmux/port 1 scanning and root compromises on IRIX based systems.  It is
believed that a new methodology is being used to identify SGI IRIX based
systems on the Internet, in order to target them for potential attack and
compromise.  This bulletin describes measures to prevent exposure to this
new methodology.

The following security bulletin is provided as a service to AusCERT's
members.  As AusCERT did not write this document, AusCERT has had no
control over its content.  As such, the decision to use any or all of this
information is the responsibility of each user or organisation, and should
be done so in accordance with site policies and procedures.

NOTE: This is only the original release of the security bulletin.  It will
not be updated when the original bulletin is.  If downloading at a later
date, it is recommended that the bulletin is retrieved from the original
authors to ensure that the information is still current.

Contact information for SGI is included in the Security Bulletin below.
If you have any questions or need further information, please contact them

Previous advisories and external security bulletins can be retrieved from:


If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security

Internet Email: auscert@auscert.org.au
Facsimile:	(07) 3365 7031
Telephone:	(07) 3365 4417 (International: +61 7 3365 4417)
		AusCERT personnel answer during Queensland business hours
		which are GMT+10:00 (AEST).
		On call after hours for emergencies.

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                Silicon Graphics Inc. Security Advisory

        Title:   tcpmux Port Scanning and Root Compromises
        Number:  19980503-01-I
        Date:    May 28, 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.

Silicon Graphics has been in communication with the CERT Coordination
Center in regards to observed increases in tcpmux/port 1 scanning and 
root compromises on IRIX based systems.

Upon examining this trend, Silicon Graphics and the CERT Coordination
Center have theorized that a new methodology is currently being used
to identify the continually increasing number of Silicon Graphics IRIX 
based systems on the Internet, in order to then target them for potential 
attack and compromise.

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

Silicon Graphics believes at this time that no new IRIX vulnerability has 
been found.  However, this new methodology is based upon an understanding 
of the default IRIX environment and could lead to a system compromise. 

The tcpmux protocol is used by many computing platforms.   By default, 
Silicon Graphics based IRIX systems have the tcpmux protocol activated 
for use on port 1.  Utilizing this fact, widespread scanning of networks 
for systems that respond to probes of port 1 could be used to obtain a 
list of systems that might be running IRIX.  Again, at this time, there 
is no known vulnerability in the tcpmux protocol or the services it 
provides and responding to a probe of port 1 is normal behavior for 
the tcpmux protocol.

Using a scan generated list, the next component of the methodology would 
be to attempt to exploit IRIX-specific security problems.  This may include
attempting to log into well known accounts that are unpassworded by default 
and upon successfully finding any open default account, attempting security 
exploits requiring local account access.   These accounts are shipped unpassworded 
by default to foster a "collaborative" environment and are documented in SGI
system documentation and also in SGI security advisory 19951002.

Additionally, the scan generated list could be used to target systems for
remote exploits, which do not require local account access.

In both local and remote cases, a system compromise is possible if security 
patches have not been installed and/or the system is misconfigured.   

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

At this time, Silicon Graphics does not believe any new vulnerability
exists in regards to this issue and therefore has no patches to offer.  
All current security patches and information can be found at: 


Silicon Graphics believes the best measures for preventing exposure
to this new methodology is to 1) ensure all accounts have good passwords
or are disabled, and 2) that all current security patches are installed.

Furthermore, keeping current with new security information and system 
monitoring for intrusions would be considered prudent.

If your IRIX machine currently has unpassworded accounts, it would
be prudent to inspect your system for signs of intrusion.  Please
refer to the "Recovering from an Incident" section at the CERT 
Coordination Center website (www.cert.org).

- - ------------------------
- - --- 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


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 (  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 

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


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> 

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.


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


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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