Public Vulnerability Reports

SGI IRIX gr_osview Information Disclosure Vulnerability

04.07.05

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.

DESCRIPTION

Local exploitation of an information disclosure vulnerability in the
gr_osview command included in multiple versions of Silicon Graphics
Inc.'s IRIX Operating System could allow for the disclosure of sensitive
information such as the root user's password hash.

The vulnerability specifically exists in the way that gr_osview opens
user-specified description files without dropping privileges. When this
is combined with the debug option, it is possible to dump a line from an
arbitrary file, regardless of its protection. An example is as follows:

user@irix$ gr_osview -d -D /etc/shadow
sgets: waiting for string
*SR> read <root:PASSWDHASHHERE:2051::::::>
gr_osview: description file format error on line 1  

To elevate privileges, the attacker would then have to crack the root
password using the acquired hash.

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. The most effective exploitation method would be
reading the first line of the operating system shadow file and then
attempting to crack the root password hash. If successful, this would
lead to a full root compromise.

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.

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

VENDOR RESPONSE

This vulnerability has been addressed in SGI BUG 930892.

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/

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2005-0464 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

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

CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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LEGAL NOTICES

Copyright © 2005 Verisign, Inc.

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at the time of publishing based on currently available information. Use
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