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ESB-2007.0533 -- [Win][UNIX/Linux][Solaris][AIX][OSX] -- IBM Tivoli Provisioning Manager for OS Deployment TFTP Blocksize DoS Vulnerability

Date: 18 July 2007

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             AUSCERT External Security Bulletin Redistribution

           ESB-2007.0533 -- [Win][UNIX/Linux][Solaris][AIX][OSX]
          IBM Tivoli Provisioning Manager for OS Deployment TFTP
                        Blocksize DoS Vulnerability
                               18 July 2007


        AusCERT Security Bulletin Summary

Product:              IBM Tivoli Provisioning Manager
Publisher:            iDefense
Operating System:     UNIX variants (UNIX, Linux, OSX)
Impact:               Denial of Service
Access:               Remote/Unauthenticated
CVE Names:            CVE-2007-3268

Original Bulletin:

- --------------------------BEGIN INCLUDED TEXT--------------------

IBM Tivoli Provisioning Manager for OS Deployment TFTP Blocksize DoS

iDefense Security Advisory 07.17.07
Jul 17, 2007


IBM Corp.'s Tivoli Provisioning Manager for OS Deployment is a network
boot server that facilitates central management of networked
workstations. It implements Preboot Execution Environment (PXE), a
Web-based administration service, DHCP, TFTP, and several additional
protocols. More information can be found at the following URL.


Remote exploitation of a denial of service vulnerability within version of IBM Corp.'s Tivoli Provisioning Manager for OS Deployment
allows attackers to deny service to all product functionality.

This vulnerability specifically exists in the TFTP protocol
implementation. When processing a read request (RRQ), an integer
division by zero error can be triggered by supplying an invalid
"blksize" argument. This exception is not handled and will result in
the rembo.exe service terminating.


Exploitation allows an attacker to cause the service to terminate
unexpectedly due to an exception that occurs when dividing by zero.

No authentication is required to access the vulnerable code. The
attacker need only be able to send a specially crafted request to the
TFTP port (UDP port 69) of the vulnerable machine.

This will deny service to all functionality provided by this service.
This includes DHCP, TFTP, PXE, HTTP, HTTPS, as well as several other


iDefense has confirmed the existence of this vulnerability in version of IBM Corp.'s Tivoli Provisioning Manager for OS Deployment.
Version was tested and found not to be vulnerable.


Employing firewalls to limit access to the affected service will
mitigate exposure to this vulnerability.


The IBM Tivoli team has addressed this vulnerability within Tivoli
Provisioning Manager for OS Deployment 5.1 Fix Pack 3. More information
is available from IBM Document swg24016347 at the following URL.


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-3268 to this issue. This is a candidate for inclusion in
the CVE list (, which standardizes names for
security problems.


06/19/2007  Initial vendor notification
06/19/2007  Initial vendor response
07/17/2007  Coordinated public disclosure


This vulnerability was reported to iDefense by Manuel Santamarina

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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 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.

- --------------------------END INCLUDED TEXT--------------------

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