May 2006

ID: 00359
Ref: 352/06
Date: 20 May 2006:15:33:21
Version: 1

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Title: Microsoft Word Vulnerability
Abstract: UNIRAS is current monitoring reports of the exploitation of a new as yet unpatched Microsoft Word Vulnerability. The exploit downloads a backdoor that has rootkit-like components.
Vendors affected: Microsoft
Operating systems affected: Microsoft
Applications affected: Microsoft

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UNIRAS is current monitoring reports of the exploitation of a new as yet unpatched
Microsoft Word Vulnerability. The exploit downloads a backdoor that has rootkit-like
components.

Reports indicate that the backdoor once active on a compromised system connects
to a specified host and has the capabilities of receiving commands. These commands
can completely control the victim's infected machine. The backdoor has the ability
to control services, files and to send system-information or screenshots to the
commanding system. A command can also be sent that allows the hacker to open up a
remote command shell to the infected machine.

In order for the attack to be carried out, a user must first open a malicious Word
document attached to an e-mail or otherwise provided to them by an attacker.

Additional Information:

Microsoft have released the following preliminary information:
http://blogs.technet.com/msrc/archive/2006/05/19/429353.aspx

SANS ISC have a list of suggested mitigations:
http://isc.sans.org/diary.php?storyid=1347

Earlier analysis at:
http://isc.sans.org/diary.php?storyid=1345
http://isc.sans.org/diary.php?storyid=1346


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National Cyber Alert System

Technical Cyber Security Alert TA06-139A


Microsoft Word Vulnerability

Original release date: May 19, 2006
Last revised: --
Source: US-CERT


Systems Affected

* Microsoft Word 2003
* Microsoft Word XP (2002)

Microsoft Word is included in Microsoft Works Suite and Microsoft
Office. Other versions of Word, and other Office programs may be
affected or act as attack vectors.


Overview

A buffer overflow vulnerability in Microsoft Word could allow an
attacker to execute arbitrary code on a vulnerable system.


I. Description

Microsoft Word contains a buffer overflow vulnerability. Opening a
specially crafted Word document, including documents hosted on web
sites or attached to email messages, could trigger the
vulnerability.

Office documents can contain embedded objects. For example, a
malicious Word document could be embedded in an Excel or PowerPoint
document. Office documents other than Word documents could be used
as attack vectors.

For more information, please see Vulnerability Note VU#446012.


II. Impact

By convincing a user to open a specially crafted Word document, an
attacker could execute arbitrary code on a vulnerable system. If
the user has administrative privileges, the attacker could gain
complete control of the system.


III. Solution

At the time of writing, there is no complete solution available.
Consider the following workarounds:

Do not open untrusted Word documents

Do not open unfamiliar or unexpected Word or other Office
documents, including those received as email attachments or hosted
on a web site. Please see Cyber Security Tip ST04-010 for more
information.

Do not rely on file extension filtering

In most cases, Windows will call Word to open a document even if
the document has an unknown file extension. For example, if
document.d0c (note the digit "0") contains the correct file header
information, Windows will open document.d0c with Word.


Appendix A. References

* Vulnerability Note VU#446012 -


* Cyber Security Tip ST04-010 -



____________________________________________________________________

Information used in this document came from SANS and Microsoft.
____________________________________________________________________

The most recent version of this document can be found at:


____________________________________________________________________

Feedback can be directed to US-CERT Technical Staff. Please send
email to with "TA06-139A Feedback VU#446012" in the
subject.
____________________________________________________________________

For instructions on subscribing to or unsubscribing from this
mailing list, visit .
____________________________________________________________________

Produced 2006 by US-CERT, a government organization.

Terms of use:


____________________________________________________________________


Revision History

May 19, 2006: Initial release

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