iDEFENSE Security Advisory 04.07.05: SGI IRIX gr_osview File Overwrite Vulnerability

SGI IRIX gr_osview File Overwrite Vulnerability

iDEFENSE Security Advisory 04.07.05
http://www.idefense.com/application/poi/display?type=vulnerabilities
April 7, 2005

I. BACKGROUND

The gr_osview application is a setuid root application that provides a
graphical display of usage of certain types of operating system
resources. It is installed by default under multiple versions of IRIX 6.

II. DESCRIPTION

Local exploitation of a file overwrite vulnerability in the gr_osview
command included in multiple versions of Silicon Graphics Inc.'s IRIX
operating system could allow for the overwriting of arbitrary files,
regardless of permissions.

The vulnerability specifically exists in the way that gr_osview opens
user specified files without dropping privileges. When a file is
specified using the "-s" option, it will be opened regardless of
permissions, and operating system usage information will be written into

it. An example follows:

user@irix$ gr_osview -s /etc/shadow

After execution of that command, the system shadow file will be
overwritten with system usage information. With a damaged shadow file,
users will no longer be able to log on remotely or locally.

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 computer. Exploitation does not require any
knowledge of application internals, making exploitation trivial, even
for unskilled attackers.

IV. DETECTION

iDEFENSE has confirmed the existence of this vulnerability in SGI IRIX
version 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 using:

chmod u-s /usr/sbin/gr_osview

VI. VENDOR RESPONSE

This vulnerability has been addressed in SGI BUG 930890.

Related security advisories are available at:
http://www.sgi.com/support/security/advisories.html

Related patches are available at:
http://www.sgi.com/support/security/patches.html
ftp://patches.sgi.com/support/free/security/patches/

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2005-0465 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

02/18/2005 Initial vendor notification
02/23/2005 Initial vendor response
04/07/2005 Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright (c) 2005 iDEFENSE, 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 [email protected] 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.