SGI IRIX inpview Design Error Vulnerability

iDEFENSE Security Advisory 01.13.05
www.idefense.com/application/poi/display?id=182&type=vulnerabilities
January 13, 2005

I. BACKGROUND

The inpview program is a setuid root application that is included in the

InPerson networked multimedia conferencing tool. InPerson networked 
multimedia conferencing tool is included in SGI IRIX.

II. DESCRIPTION

Local exploitation of a design error vulnerability in the inpview 
command included in multiple versions of Silicon Graphics Inc.'s IRIX 
could allow for arbitrary code execution as the root user. 

The vulnerability specifically exists due to the fact that inpview 
trusts the user environment and does not drop privileges. When the 
environment variable SUN_TTSESSION_CMD is something such as "cp /bin/jsh

/tmp/jsh;chmod 6755 /tmp/jsh;killall -9 inpview," the chain of commands 
will be executed with root permissions, thus allowing a regular user to 
drop a setuid and setgid shell to /tmp.

III. ANALYSIS

All that is required to exploit this vulnerability is a local account 
and an open X display, which could be the attacker's home machine or 
another compromised system. Exploitation does not require any knowledge 
of application internals, making privilege escalation trivial, even for 
unskilled attackers. 

IV. DETECTION

iDEFENSE has confirmed the existence of this vulnerability in SGI IRIX 
version 6.5.9 (feature) and 6.5.22 (maintenance). It is suspected that 
previous and later versions of both the feature and maintenance 
revisions of IRIX 6.5 are also vulnerable.

V. WORKAROUND

Only allow trusted users local access to security critical systems.

Alternately, remove the setuid bit from inpview: 

   chmod u-s /usr/lib/InPerson/inpview

VI. VENDOR RESPONSE

Support for the InPerson product did not extend beyond 02/2002 as noted
in the following publication:

 techpubs.sgi.com/library/manuals/4000/007-4526-001/pdf/007-4526-001.pdf

As a result, no patch will be issued for this vulnerability.

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

01/06/2005  Initial vendor notification
01/07/2005  Initial vendor response
01/13/2005  Public disclosure

IX. CREDIT

iDEFENSE Labs is credited with this discovery.

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X. LEGAL NOTICES

Copyright (c) 2004 iDEFENSE, Inc.

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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
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