[NT] IBM Tivoli Provisioning Manager for OS Deployment TFTP Blocksize DoS Vulnerability

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IBM Tivoli Provisioning Manager for OS Deployment TFTP Blocksize DoS
Vulnerability
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SUMMARY

<http://www-306.ibm.com/software/tivoli/products/prov-mgr-os-deploy/ >
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".

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

DETAILS

Vulnerable Systems:
* IBM Corp.'s Tivoli Provisioning Manager for OS Deployment version
5.1.0.2

Immune Systems:
* IBM Corp.'s Tivoli Provisioning Manager for OS Deployment version
5.1.0.116

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 services.

Vendor Status:
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.
<http://www-1.ibm.com/support/docview.wss?uid=swg24016347>

http://www-1.ibm.com/support/docview.wss?uid=swg24016347

Disclosure Timeline:
* 06/19/2007 - Initial vendor notification
* 06/19/2007 - Initial vendor response
* 07/17/2007 - Coordinated public disclosure

ADDITIONAL INFORMATION

The information has been provided by iDefense.
The original article can be found at:

<http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=560>

http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=560

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