Public Vulnerability Reports

IBM AIX netpmon Local Buffer Overflow Vulnerability

02.10.05

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.

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.

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.

DETECTION

iDEFENSE has confirmed the existence of this vulnerability in IBM AIX
version 5.2. It is suspected that previous versions are also vulnerable.

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

VENDOR RESPONSE

Vendor advisories for this issue are available at:

For AIX 5.1:

https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mode=1&heading=AIX51&topic=SECURITY&month=ALL

For AIX 5.2:

https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mode=1&heading=AIX52&topic=SECURITY&month=ALL

For AIX 5.3:

https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mode=1&heading=AIX53&topic=SECURITY&month=ALL

CVE INFORMATION

 The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2005-0263 these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

DISCLOSURE TIMELINE

12/21/2004   Initial vendor notification
01/07/2004   Initial vendor response
02/10/2005   Coordinated public disclosure

CREDIT

iDEFENSE Labs is credited with this discovery

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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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