Airscanner Mobile Security Advisory #05081101:
vxWeb v.1.1.4 Denial of Service Vulnerability 

Product:
vxWeb v1.1.4

Platform:
Tested on Windows Mobile Pocket PC 2003

Requirements:
Mobile device running Windows Mobile Pocket PC with vxWeb v1.1.4 installed and running. 

Credits:
Seth Fogie
Airscanner Mobile Security
https://www.airscanner.com
Mobile Antivirus Researchers Association
https://www.mobileav.org
August 11 2005

Risk Level:
Low

Summary:
vxWeb is a complete multi-threaded web server for Windows CE-based devices. However, it is vulnerable to a stack based buffer overflow that results in an instant crash of the web server. 

Details:
GET /Ax1000
.text:0001C310 BL __2_YAPAXI_Z ; operator new(uint)

The YAPAXI or set(UINT) command (located in coredll.dll) ends up reading data off the stack which can be overwritten by a long request. As a result, code in coredll.dll will be fed invalid datatypes, an exception will be thrown, and the web server will crash. We were not able to get code into the program counter (PC). We were able to manually insert values that permitted the yapaxi function to continue on, but this did not result in any other interesting results. 

Workaround:
None

Vendor Response:
Waiting response.

Copyright (c) 2005 Airscanner Corp.

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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 on 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.

advisory
https://www.airscanner.com/security/05081101_vxweb.htm