iDefense Security Advisory 01.23.08
http://labs.idefense.com/intelligence/vulnerabilities/
Jan 23, 2008

I. BACKGROUND

The pioout program is a set-uid root application, installed by default
under multiple versions of IBM AIX, that is used to interface with the
printer driver. For more information, visit the following URL.

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/topic/com.ibm.aix.cmds/doc/aixcmds4/pioout.htm

II. DESCRIPTION

Local exploitation of a buffer overflow vulnerability in IBM Corp.'s AIX
operating system 'pioout' program allows attackers to execute arbitrary
code with root privileges.

The vulnerability exists due to insufficient input validation when
copying user-supplied data to a fixed-size buffer. By passing a long
string as a command line option, an attacker can cause an exploitable
buffer overflow.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary
code with root privileges. In order to exploit this vulnerability, an
attacker must have access to execute the set-uid root 'pioout' program.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in version
5.2 and 5.3 of AIX with all patches applied as of November 29th, 2007.
Previous versions are suspected to be affected.

V. WORKAROUND

Removing the set-uid bit from the binary will prevent exploitation, but
will also make the program unusable by non-root users.

VI. VENDOR RESPONSE

IBM Corp. has addressed this vulnerability by releasing interim fixes.
More information can be found via the Bulletins tab of IBM's
Subscription Service for UNIX and Linux servers. You can reach this
service by clicking the URL shown below.

http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd?mode=1

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-5764 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

11/29/2007  Initial vendor notification
12/03/2007  Initial vendor response
01/23/2008  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright © 2008 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
of the information constitutes acceptance for use in an AS IS condition.
 There are no warranties with regard to this information. Neither the
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