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CA-2003-22 Multiple Vulnerabilities in Microsoft Internet Explorer


CERT Advisory CA-2003-22 Multiple Vulnerabilities in Microsoft
Internet Explorer

Original issue date: August 26, 2003
Last revised: --
Source: CERT/CC

A complete revision history is at the end of this file.

Systems Affected

Microsoft Windows systems running

* Internet Explorer 5.01
* Internet Explorer 5.50
* Internet Explorer 6.01

Previous, unsupported versions of Internet Explorer may also be


Microsoft Internet Explorer (IE) contains multiple vulnerabilities,
the most serious of which could allow a remote attacker to execute
arbitrary code with the privileges of the user running IE.

I. Description

Microsoft Security Bulletin MS03-032 describes five vulnerabilities
in Internet Explorer. These vulnerabilities are listed below.
More detailed information is available in the individual
vulnerability notes. Note that in addition to IE, any applications
that use the IE HTML rendering engine to interpret HTML documents
may present additional attack vectors for these vulnerabilities.

VU#205148 - Microsoft Internet Explorer does not properly evaluate
Content-Type and Content-Disposition headers

A cross-domain scripting vulnerability exists in the way IE
evaluates Content-Type and Content-Disposition headers and checks
for files in the local browser cache. This vulnerability could
allow a remote attacker to execute arbitrary script in a
different domain, including the Local Machine Zone.
(Other resources: SNS Advisory No.67, CAN-2003-0531)

VU#865940 - Microsoft Internet Explorer does not properly evaluate
"application/hta" MIME type referenced by DATA attribute of OBJECT

IE will execute an HTML Application (HTA) referenced by the DATA
attribute of an OBJECT element if the Content-Type header
returned by the web server is set to "application/hta". An
attacker could exploit this vulnerability to execute arbitrary
code with the privileges of the user running IE.
(Other resources: eEye Digital Security Advisory AD20030820,

VU#548964 - Microsoft Windows BR549.DLL ActiveX control contains

The Microsoft Windows BR549.DLL ActiveX control, which provides
support for the Windows Reporting Tool, contains an unknown
vulnerability. The impact of this vulnerability is not known.

VU#813208 - Internet Explorer does not properly render an input
type tag

IE does not properly render an input type tag, allowing a remote
attacker to cause a denial of service.

VU#334928 - Microsoft Internet Explorer contains buffer overflow in
Type attribute of OBJECT element on double-byte character set

Certain versions of IE that support double-byte character sets
(DBCS) contain a buffer overflow vulnerability in the Type
attribute of the OBJECT element. A remote attacker could execute
arbitrary code with the privileges of the user running IE.
(Other resources: SNS Advisory No.68, Microsoft Security Bulletin
MS03-020, CAN-2003-0344)

II. Impact

These vulnerabilities have different impacts, ranging from denial
of service to execution of arbitrary commands or code. Please see
the individual vulnerability notes for specific information. The
most serious of these vulnerabilities (VU#865940) could allow a
remote attacker to execute arbitrary code with the privileges of
the user running IE. The attacker could exploit this vulnerability
by convincing the user to access a specially crafted HTML document,
such as a web page or HTML email message. No user intervention is
required beyond viewing the attacker's HTML document with IE.

III. Solution

Apply a patch

Apply the appropriate patch as specified by Microsoft Security
Bulletin MS03-032.

In addition to addressing these vulnerabilities, the patch also
changes the behavior of the HTML Help system (see VU#25249):

As with the previous Internet Explorer cumulative patches
released with bulletins MS03-004, MS03-015, and MS03-020 this
cumulative patch will cause window.showHelp() to cease to
function if you have not applied the HTML Help update. If you
have installed the updated HTML Help control from Knowledge Base
article 811630, you will still be able to use HTML Help
functionality after applying this patch.

Appendix A. Vendor Information

This appendix contains information provided by vendors. When
vendors report new information, this section is updated and the
changes are noted in the revision history. If a vendor is not
listed below, we have not received their comments.


Please see Microsoft Security Bulletin MS03-032.

Appendix B. References

* CERT/CC Vulnerability Note VU#205148 -

* CERT/CC Vulnerability Note VU#865940 -

* CERT/CC Vulnerability Note VU#548964 -

* CERT/CC Vulnerability Note VU#813208 -

* CERT/CC Vulnerability Note VU#334928 -

* CERT/CC Vulnerability Note VU#25249 -

* eEye Digital Security Advisory AD20030820 -

* SNS Advisory No. 67 -

* SNS Advisory No. 68 -

* Microsoft Security Bulletin MS03-032 -

* Microsoft KB Article 822925 -


Microsoft credits eEye Digital Security, LAC, and KPMG UK for
reporting these vulnerabilities. Information from eEye, LAC, and
Microsoft was used in this document.

Feedback can be directed to the author, Art Manion.

This document is available from:

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Revision History

August 26, 2003: Initial release

Version: PGP 6.5.8


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