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Category:   Application (Directory)  >   Novell eDirectory Vendors:   Novell
Novell eDirectory NCP Fragment Processing Bug Lets Remote Users Deny Service
SecurityTracker Alert ID:  1017972
SecurityTracker URL:
CVE Reference:   CVE-2006-4520   (Links to External Site)
Date:  Apr 27 2007
Impact:   Denial of service via network
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): and prior version, 8.8, 8.8.1
Description:   A vulnerability was reported in Novell eDirectory. A remote user can cause denial of service conditions.

A remote user can send specially crafted NCP fragment requests to cause the target service to stop processing requests.

The vendor was notified on August 17, 2006.

iDefense reported this vulnerability.

Impact:   A remote user can cause the target service to stop processing requests.
Solution:   The vendor has issued a fix (FTF2 for eDirectory 8.8.1).

The Novell advisory is available at:

Vendor URL: (Links to External Site)
Cause:   Input validation error
Underlying OS:  Linux (Any), UNIX (AIX), UNIX (Solaris - SunOS), Windows (2000), Windows (2003), Windows (XP)

Message History:   None.

 Source Message Contents

Subject:  iDefense Security Advisory 04.26.07: Novell eDirectory NCP Fragment

Novell eDirectory NCP Fragment Denial of Service Vulnerability

iDefense Security Advisory 04.26.07
Apr 26, 2007


Novell eDirectory is a cross-platform lightweight directory access
protocol (LDAP) server. In addition to LDAP, eDirectory also implements
NCP over IP. More information can be found on Novell's web site at the
following URL.


Remote exploitation of a denial of service (DoS) vulnerability in Novell
Inc.'s eDirectory product could allow an attacker to force the running
daemon to cease servicing requests.

The problem specifically exists within the NCP functionality of
eDirectory. Sending a sequence of specially crafted fragmented requests
will cause a DoS condition.

If the input is crafted properly, eDirectory will report to its error
log that a fragment has been received with an invalid length. The error
message includes the contents of the fragments in hexadecimal notation.
However, if the length is negative, eDirectory will try to dump data to
the log indefinitely. This results in a large amount of data being saved
to the log. Once the end of the heap segment is reached, a memory access
violation will occur and the server process will crash.


Successful exploitation of this vulnerability could allow an attacker to
crash the server process. No credentials are required. Repeated attacks
could allow the attacker to cause excessive disk space usage.


iDefense has confirmed the existence of this vulnerability in version
8.8.1 of Novell Inc.'s eDirectory server with FTF1 applied. The
earliest version tested was 8.8. Earlier versions are suspected to be


iDefense is unaware of any effective workaround for this issue.


Novell has addressed this problem within FTF2 for eDirectory 8.8.1. More
information is available in Novell Document ID 3924657 at the following


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-4520 to this issue. This is a candidate for inclusion in
the CVE list (, which standardizes names for
security problems.


08/17/2006  Initial vendor notification
08/18/2006  Initial vendor response
10/21/2006  Second vendor notification
10/23/2006  Vendor response
12/06/2006  Third vendor notification
12/18/2006  Vendor response
03/21/2007  Fourth vendor notification
04/25/2007  Fifth vendor notification
04/25/2007  Vendor advised that the fix was in FTF2
04/26/2007  Coordinated public disclosure


The discoverer of this vulnerability wishes to remain anonymous.

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