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iDefense Security Advisory 10.21.06: Novell eDirectory evtFilteredMonitorEventsRequest Heap Overflow Vulnerability



Novell eDirectory evtFilteredMonitorEventsRequest Heap Overflow
Vulnerability

iDefense Security Advisory 10.21.06
http://www.idefense.com/intelligence/vulnerabilities/
Oct 21, 2006

I. BACKGROUND

Novell eDirectory is a cross-platform lightweight directory access
protocol (LDAP) server. More information can be found on Novell's
web site at http://www.novell.com/products/edirectory/

II. DESCRIPTION

Remote exploitation of a heap overflow vulnerability in Novell Inc.'s
eDirectory product could allow an attacker to execute arbitrary code in
the context of the running daemon.

This problem stems from an integer overflow that occurs when allocating
memory for attacker supplied data. The evtFilteredMonitorEventsRequest
function takes user input and multiplies it by 16, then adds 16 without
first validating that an integer overflow will not occur. If allocation
succeeds, the function will proceed to loop, filling the memory with
partially controllable input. Since the loop is bounded directly by the
attacker supplied length value, heap overflow will occur.

III. ANALYSIS

Successful exploitation of this vulnerability could allow an attacker to
crash the server or execute arbitrary code. No credentials are required.
Typically this daemon runs with administrator privileges.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in version
8.8.1 of Novell Inc.'s eDirectory server. Version 8.8 was also tested
and found to be vulnerable. Earlier versions are suspected to be
vulnerable.

V. WORKAROUND

It is possible to disable the LDAP service from running via the
ndsmodules.conf file which is usually located in
/etc/opt/novell/eDirectory/conf. However, doing so greatly reduces the
functionality of this program.

VI. VENDOR RESPONSE

Novell has addressed this vulnerability with eDirectory 8.8.1 FTF1.

You can obtain the Linux/Unix version of this update from their site at:
http://support.novell.com/servlet/filedownload/sec/pub/edir881ftf_1.tgz/
The windows version of this update is available at:
http://support.novell.com/servlet/filedownload/sec/pub/edir881ftf_1.exe/

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-4509 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

08/17/2006  Initial vendor notification
08/18/2006  Initial vendor response
10/06/2006  Second vendor notification
10/20/2006  Vendor update released
10/21/2006  Public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright © 2006 iDefense, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
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part of this alert in any other medium other than electronically, please
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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
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.