IBM AIX pioout Arbitrary Library Loading Vulnerability iDefense Security Advisory 07.26.07 http://labs.idefense.com/intelligence/vulnerabilities/ Jul 26, 2007 I. BACKGROUND The pioout program is a setuid root application, installed by default under multiple versions of IBM AIX, that is used to interface with the printer driver. More information can be found at 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 an arbitrary library loading vulnerability in the 'pioout' program, as included with IBM Corp.'s AIX operating system, allows an attacker to execute arbitrary code with root privileges. The vulnerability exists due to the application loading an arbitrary shared library provided by the attacker, without dropping privileges. Using the -R command line argument, an attacker can specify a shared library used to parse data coming from the printer. III. ANALYSIS Exploitation of this vulnerability results in the execution of arbitrary code with root privileges. The pioout program is setuid root, and executable by any user with local access. To exploit the vulnerability, all an attacker has to do is create a shared library that executes a shell. IV. DETECTION iDefense has confirmed the existence of this vulnerability in AIX version 5.3 with service pack 6. Previous versions may also be affected. V. WORKAROUND Removing the setuid bit from the binary will prevent exploitation, but may 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-2007-4003 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 06/05/2007 Initial vendor notification 06/08/2007 Initial vendor response 07/26/2007 Coordinated public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 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 e-mail customerservice@private 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.
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