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Microsoft Windows kernel vulnerable to denial-of-service condition via animated cursor (.ani) rate number

Vulnerability Note VU#697136

Original Release Date: 2005-01-07 | Last Revised: 2005-03-14


A vulnerability exists in the way the Microsoft Windows kernel processes animated cursor (.ani) files with a rate number set to zero. Exploitation of this vulnerability may allow a remote attacker to cause a denial-of-service condition.


A vulnerability exists in the way the Microsoft Windows kernel processes .ani files. These files contain animated graphics for icons and cursors. According to public reports, if the Windows kernel is supplied a .ani file with a rate number set to zero, it doesn't properly handle the .ani file. As a result, the kernel may crash or consume 100% of the system resources resulting in a denial-of-service condition.

.ani files are parsed when the containing folder is opened or it is used as a cursor. In addition, Internet Explorer can process .ani files in HTML documents, so web pages and HTML email messages can also trigger this vulnerability. Other web browsers or programs that render HTML may also act as attack vectors.

Note that it is reported that Windows XP SP2 is not affected by this issue.


If a remote attacker can persuade a user to access a specially crafted .ani file, the attacker may be able to crash that user's system.


Apply Patch

Apply a patch as described in Microsoft Security Bulletin MS05-002. Please also note that Microsoft is actively deploying the patches for this vulnerability via Windows Update.

Vendor Information


Microsoft Corporation Unknown

Notified:  January 07, 2005 Updated: January 11, 2005



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


If you have feedback, comments, or additional information about this vulnerability, please send us email.

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This vulnerability was publicly reported by Sylvain Bruyere.

This document was written by Jeff Gennari.

Other Information

CVE IDs: CVE-2004-1305
Severity Metric: 28.35
Date Public: 2004-12-23
Date First Published: 2005-01-07
Date Last Updated: 2005-03-14 15:35 UTC
Document Revision: 48

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