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

Vulnerability Note VU#177584

Original Release Date: 2005-01-07 | Last Revised: 2014-04-23


A vulnerability exists in the way the Microsoft Window's kernel processes animated cursor (.ani) files with a frame 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 frame 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

Updated:  January 11, 2005



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.


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

CVSS Metrics

Group Score Vector
Base 0 AV:--/AC:--/Au:--/C:--/I:--/A:--
Temporal 0 E:ND/RL:ND/RC:ND
Environmental 0 CDP:ND/TD:M/CR:ND/IR:ND/AR:ND



This vulnerability was reported to Microsoft 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: 2014-04-23 22:16 UTC
Document Revision: 92

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