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CERT Coordination Center

Microsoft Internet Explorer CSS style element vulnerability

Vulnerability Note VU#515749

Original Release Date: 2009-11-25 | Last Revised: 2009-11-27


Microsoft Internet Explorer (IE) does not safely reference CSS style elements. Using a specially crafted HTML page, an attacker can cause IE to crash and potentially execute arbitrary code.


IE contains a vulnerability in the way it references CSS style elements. Processing a specially crafted HTML page could cause IE to access an invalid memory location and crash. Using heap-spraying techniques, an attacker could leverage the crash to execute arbitrary code.

Please see Microsoft Security Advisory (977981).


By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message), an attacker could execute arbitrary code with the privileges of the user.


A complete solution is not available.

Disable Active scripting

As noted in Microsoft Security Advisory (977981), consider disabling Active Scripting. Instructions for disabling Active scripting can be found in Microsoft Security Advisory (977981 and "Securing Your Web Browser."

Enable DEP

As noted in Microsoft Security Advisory (977981), consider enabling Data Execution Prevention (DEP).

Disabling scripting and enabling DEP do not resolve the vulnerability, but they greatly lower the chances of an attacker being able to execute arbitrary code.

Use Internet Explorer 8

According to Microsoft Security Advisory (977981), Internet Explorer 8 is not affected.

Vendor Information

Affected   Unknown   Unaffected

Microsoft Corporation

Notified:  November 23, 2009 Updated:  November 24, 2009



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

Please see Microsoft Security Advisory (977981).

Vendor References

CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A



This vulnerability was publicly disclosed by and/or

This document was written by Art Manion.

Other Information

CVE IDs: CVE-2009-3672
Severity Metric: 29.25
Date Public: 2009-11-20
Date First Published: 2009-11-25
Date Last Updated: 2009-11-27 19:09 UTC
Document Revision: 15

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