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SGI IRIX inpview Design Error Vulnerability

01.13.05

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.

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.

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.

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.

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

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.

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2005-0113 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

DISCLOSURE TIMELINE

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

CREDIT

iDEFENSE Labs is credited with this discovery.

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LEGAL NOTICES

Copyright © 2004 Verisign, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDEFENSE. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email customerservice@idefense.com for permission.

Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.