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TUCoPS :: Windows Apps :: n-114.txt
Buffer Overrun in Microsoft HTML Converter Could Allow Code Execution (CIAC N-114)

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The U.S. Department of Energy
Computer Incident Advisory Capability
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INFORMATION BULLETIN

Buffer Overrun in Microsoft HTML Converter Could Allow Code Execution
[Microsoft Security Bulletin MS03-023]

July 10, 2003 17:00 GMT Number N-114
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PROBLEM: There is a flaw in the way the HTML converter for Microsoft
Windows handles a conversion request during a cut-and-paste
operation. A specially crafted request to the HTML converter
could cause the converter to fail in such a way that it could
execute code in the context of the currently logged-in user.
SOFTWARE: * Microsoft Windows 98
* Microsoft Windows 98 Second Edition
* Microsoft Windows Me
* Microsoft Windows NT 4.0 Server
* Microsoft Windows NT 4.0 Terminal Server Edition
* Microsoft Windows 2000
* Microsoft Windows XP
* Microsoft Windows Server 2003
DAMAGE: Because this functionality is used by Internet Explorer, an
attacker could craft a specially formed Web page or HTML e-mail
that would cause the HTML converter to run arbitrary code on a
user's system.
SOLUTION: Apply patches as stated in Microsoft's security bulletin.
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VULNERABILITY The risk is MEDIUM. To exploit this vulnerability, the attacker
ASSESSMENT: would have to create a specially-formed HTML e-mail and send it
to the user. The attacker would have to host a Web site that
contained a Web page used to exploit this vulnerability, and
persuade a user to visit that site.
______________________________________________________________________________
LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-114.shtml
ORIGINAL BULLETIN:
http://www.microsoft.com/technet/treeview/
default.asp?url=/technet/security/bulletin/MS03-023.asp
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[***** Start Microsoft Security Bulletin MS03-023 *****]

Microsoft Security Bulletin MS03-023

Buffer Overrun In HTML Converter Could Allow Code Execution (823559)
Originally posted: July 9, 2003

Summary
Who should read this bulletin: Users running Microsoft ® Windows ®

Impact of vulnerability: Run code of attacker’s choice

Maximum Severity Rating: Critical

Recommendation: Systems administrators should apply the patch
immediately

Affected Software:

* Microsoft Windows 98
* Microsoft Windows 98 Second Edition
* Microsoft Windows Me
* Microsoft Windows NT 4.0 Server
* Microsoft Windows NT 4.0 Terminal Server Edition
* Microsoft Windows 2000
* Microsoft Windows XP
* Microsoft Windows Server 2003

Technical details

Technical description:

All versions of Microsoft Windows contain support for file conversion
within the operating system. This functionality allows users of Microsoft
Windows to convert file formats from one to another. In particular,
Microsoft Windows contains support for HTML conversion within the operating
system. This functionality allows users to view, import, or save files as
HTML.

There is a flaw in the way the HTML converter for Microsoft Windows handles
a conversion request during a cut-and-paste operation. This flaw causes a
security vulnerability to exist. A specially crafted request to the HTML
converter could cause the converter to fail in such a way that it could
execute code in the context of the currently logged-in user. Because this
functionality is used by Internet Explorer, an attacker could craft a
specially formed Web page or HTML e-mail that would cause the HTML
converter to run arbitrary code on a user's system. A user visiting an
attacker’s Web site could allow the attacker to exploit the vulnerability
without any other user action.

To exploit this vulnerability, the attacker would have to create a
specially-formed HTML e-mail and send it to the user. Alternatively, an
attacker would have to host a malicious Web site that contains a Web page
designed to exploit this vulnerability. The attacker would then have to
persuade a user to visit that site.

Mitigating factors:

* By default, Internet Explorer on Windows Server 2003 runs in Enhanced
Security Configuration. This default configuration of Internet Explorer
blocks automatic exploitation of this attack. If Internet Explorer Enhanced
Security Configuration has been disabled, the protections put in place that
prevent this vulnerability from being automatically exploited would be removed.

* In the Web-based attack scenario, the attacker would have to host a Web site
that contained a Web page used to exploit this vulnerability. An attacker
would have no way to force users to visit a malicious Web site outside the HTML
e-mail vector. Instead, the attacker would need to lure them there, typically
by getting them to click a link that would take them to the attacker's site.

* Exploiting the vulnerability would allow the attacker only the same privileges
as the user. Users whose accounts are configured to have few privileges on the
system would be at less risk than ones who operate with administrative privileges.

Severity Rating: Windows 98 Critical
Windows 98 Second Edition Critical
Windows Me Critical
Windows NT 4.0 Server Critical
Windows NT 4.0 Terminal Server Edition Critical
Windows 2000 Critical
Windows XP Critical
Windows Server 2003 Moderate

The above assessment is based on the types of systems affected by the vulnerability,
their typical deployment patterns, and the effect that exploiting the vulnerability
would have on them.

Vulnerability identifier: CAN-2003-0469

Tested Versions:
Microsoft tested Windows 98, Windows 98 Second Edition, Windows Me, Windows NT 4.0
Server, Windows NT 4.0 Terminal Services Edition, Windows 2000, Windows XP and
Windows Server 2003 to assess whether they are affected by this vulnerability.
Previous versions are no longer supported, and may or may not be affected by these
vulnerabilities.

Patch availability

Download locations for this patch

* Windows NT 4.0 Server
* Windows NT 4.0 Terminal Server Edition
* Windows 2000
* Windows XP 32 bit Edition
* Windows XP 64 bit Edition
* Windows Server 2003 32 bit Edition
* Windows Server 2003 64 bit Edition

Additional information about this patch

Installation platforms:

* The Window 98 patch can be installed on systems running Windows 98 Gold.
* The Window 98 Second Edition patch can be installed on systems running Windows
98SE Gold.
* The Windows Me patch can be installed on systems running Windows Me Gold.
* The Windows NT 4.0 patch can be installed on systems running Service Pack 6a.
* The Windows NT 4.0, Terminal Server Edition patch can be installed on systems
running Windows NT 4.0, Terminal Server Edition Service Pack 6.
* The Windows 2000 patch can be installed on systems running Windows 2000 Service
Pack 3, or Service Pack 4.
* The patch for Windows XP can be installed on systems running Windows XP Gold or
Service Pack 1.
* The patch for Windows Server 2003 can be installed on systems running Windows
Server 2003 Gold.

Inclusion in future service packs:
The fix for this issue will be included in Windows 2000 Service Pack 5, Windows
XP Service Pack 2, and Windows Server 2003 Service Pack 1.

Reboot needed: No.

Patch can be uninstalled: Yes.

Superseded patches: None.

Verifying patch installation:

* Windows 98, Windows 98 Second Edition, Windows Me:
To verify that the patch has been installed on the machine consult the file
manifest in Knowledge Base article 823559.

* Windows NT 4.0:
To verify that the patch has been installed on the machine, confirm that all
files listed in the file manifest in Knowledge Base article 823559 are present
on the system.

* Windows NT 4.0 Terminal Server Edition:
To verify that the patch has been installed on the machine, confirm that all
files listed in the file manifest in Knowledge Base article 823559 are present
on the system.

* Windows 2000:
To verify that the patch has been installed on the machine, confirm that the
following registry key has been created on the machine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows 2000\SP5\KB823559.

To verify the individual files, use the date/time and version information
provided in the file manifest in Knowledge Base article 823559 are present on
the system.

* Windows XP:
To verify that the patch has been installed on the machine, confirm that the
following registry key has been created on the machine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP2\KB823559.

To verify the individual files, use the date/time and version information
provided in the file manifest in Knowledge Base article 823559 are present on
the system.

* Windows Server 2003:
To verify that the patch has been installed on the machine, confirm that the
following registry key has been created on the machine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Window Server 2003\SP1\KB823559.

To verify the individual files, use the date/time and version information
provided in the file manifest in Knowledge Base article 823559 are present on
the system.

Caveats:
None

Localization:
Localized versions of this patch are available at the locations discussed in
“Patch Availability”.

Obtaining other security patches:
Patches for other security issues are available from the following locations:

* Security patches are available from the Microsoft Download Center, and can be
most easily found by doing a keyword search for "security_patch".
* Patches for consumer platforms are available from the WindowsUpdate web site

Other information:

Support:

* Microsoft Knowledge Base article 823559 discusses this issue and will be
available approximately 24 hours after the release of this bulletin. Knowledge
Base articles can be found on the Microsoft Online Support web site.
* Technical support is available from Microsoft Product Support Services. There is
no charge for support calls associated with security patches.

Security Resources: The Microsoft TechNet Security Web Site provides additional
information about security in Microsoft products.

Disclaimer:
The information provided in the Microsoft Knowledge Base is provided "as is"
without warranty of any kind. Microsoft disclaims all warranties, either express
or implied, including the warranties of merchantability and fitness for a
particular purpose. In no event shall Microsoft Corporation or its suppliers be
liable for any damages whatsoever including direct, indirect, incidental,
consequential, loss of business profits or special damages, even if Microsoft
Corporation or its suppliers have been advised of the possibility of such damages.
Some states do not allow the exclusion or limitation of liability for consequential
or incidental damages so the foregoing limitation may not apply.

Revisions:

* V1.0 (July 9, 2003): Bulletin Created.

[***** End Microsoft Security Bulletin MS03-023 *****]

_______________________________________________________________________________

CIAC wishes to acknowledge the contributions of Microsoft Corporation for the
information contained in this bulletin.
_______________________________________________________________________________

CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.

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can be contacted at:
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E-mail: ciac@ciac.org

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This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
legal liability or responsibility for the accuracy, completeness, or
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