IBM AIX netpmon Local Buffer Overflow Vulnerability iDEFENSE Security Advisory 02.10.05 www.idefense.com/application/poi/display?id=197&type=vulnerabilities February 10, 2005 I. BACKGROUND The netpmon program is a setuid root application, installed by default under multiple versions of IBM AIX, which can be used to monitor activity and report statistics on network I/O and network-related CPU usage. II. DESCRIPTION Local exploitation of a buffer overflow vulnerability in the netpmon command included by default in multiple versions of IBM Corp.'s AIX Operating System could allow for arbitrary code execution as the root user. The vulnerability specifically exists due to an unbounded string copying operation into stack memory. When provided with a long argument to the -O option (the ReportType option), the netpmon process will overwrite stack memory. This allows for the execution of arbitrary code by overwriting the saved return address. III. ANALYSIS Exploitation of this vulnerability is simple for a skilled attacker, however gid "system" is required in order to execute the vulnerable binary. Successful exploitation yields root access to the system. IV. DETECTION iDEFENSE has confirmed the existence of this vulnerability in IBM AIX version 5.2. It is suspected that previous versions are also vulnerable. V. WORKAROUND Only allow trusted users local access to security critical systems; only allow trusted users access to the "system" group. Alternately, remove the setuid bit from netpmon using chmod u-s /usr/bin/netpmon VI. VENDOR RESPONSE Vendor advisories for this issue are available at: For AIX 5.1: https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mod e=1&heading=AIX51&topic=SECURITY&month=ALL For AIX 5.2: https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mod e=1&heading=AIX52&topic=SECURITY&month=ALL For AIX 5.3: https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mod e=1&heading=AIX53&topic=SECURITY&month=ALL VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 12/21/2004 Initial vendor notification 01/07/2004 Initial vendor response 02/10/2005 Coordinated public disclosure IX. CREDIT iDEFENSE Labs is credited with this discovery Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp 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 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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