Microsoft Security Bulletin (MS00-011)
--------------------------------------

Patch Available for "VM File Reading" Vulnerability
Originally Posted: February 18, 2000

Summary
=======
Microsoft has released a patch that eliminates a security vulnerability
in the Microsoft® virtual machine (Microsoft VM). The vulnerability
could enable a malicious web site operator to read files from the
computer of a person who visited his site or read web content from
inside an intranet if the malicious site is visited by a computer from
within that intranet. In both cases the malicious applet would have to
know the exact name and location of the files. Frequently asked
questions regarding this vulnerability and the patch can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-011.asp

Issue
=====
The Microsoft VM is a virtual machine for the Win32® operating
environment. It runs atop Microsoft Windows® 95, 98 or Windows NT®.
It ships as part of each operating system, and also as part of
Microsoft Internet Explorer.

The version of the Microsoft VM that ships with Microsoft Internet
Explorer 4.x and Internet Explorer 5.x contains a security
vulnerability that could allow a Java applet to operate outside the
bounds set by the sandbox. A malicious user could write a Java applet
that could read - but not change, delete or add - files from the
computer of a person who visited his site or read web content from
inside an intranet if the malicious site is visited by a computer
from within that intranet. The malicious user would need to know the
exactly path and filename of the files he wished to read.

Affected Software Versions
==========================
Versions of the Microsoft VM are identified by build numbers, which can
be determined using the JVIEW tool, as discussed in the FAQ. The
following builds of the Microsoft VM are affected:

 - All builds in the 2000 series.
 - All builds in the 3100 series.
 - All builds in the 3200 series.

Note: The Microsoft VM ships as part of several products. However, the
primary ship vehicle is Internet Explorer.

Patch Availability
==================
New versions of the Microsoft VM that include a fix for the
vulnerability can be downloaded from the following locations:

 - 2000 series builds: http://www.microsoft.com/java/vm/dl_vmsp2.htm
 - 3100 series builds: http://www.microsoft.com/java/vm/dl_vm32.htm
 - 3200 series builds: http://www.microsoft.com/java/vm/dl_vm40.htm

Note: 2000 series builds are shipped as part of Internet Explorer 4.x; 3100
series builds are shipped as part of Internet Explorer 5; 3200 series builds
are shipped as part of Internet Explorer 5.01.
Note: Additional security patches are available at the Microsoft Download
Center

More Information
================
Please see the following references for more information related to this
issue.

 - Frequently Asked Questions: Microsoft Security Bulletin MS00-011,
   http://www.microsoft.com/technet/security/bulletins/ms00-011.asp.
 - Microsoft Security Advisor web site,
   http://www.microsoft.com/security/default.asp.

Obtaining Support on this Issue
===============================
This is a fully supported patch. Information on contacting Microsoft
Technical Support is available at
http://support.microsoft.com/support/contact/default.asp.

Acknowledgments
===============
Microsoft thanks Hideo Nakamura of NEC in Tokyo, Japan for reporting the VM
File Reading vulnerability to us and working with us to protect customers.

Revisions
=========
February 18, 2000: Bulletin Created.

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Last updated Friday, February 18, 2000
© 2000 Microsoft Corporation. All rights reserved. Terms of use.

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