Vulnerability Note VU#697136

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

Overview

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.

I. Description

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.

II. Impact

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.

III. Solution

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.

Systems Affected

Vendor	Status	Date Notified	Date Updated
Microsoft Corporation	Unknown	11-Jan-2005

References

http://www.securityfocus.com/archive/1/385340
http://www.xfocus.net/flashsky/icoExp/index.html
http://secunia.com/advisories/13645/
http://www.microsoft.com/technet/security/bulletin/ms05-002.mspx

Credit

This vulnerability was publicly reported by Sylvain Bruyere.

This document was written by Jeff Gennari.

Other Information

Date Public:	2004-12-23
Date First Published:	2005-01-07
Date Last Updated:	2005-03-14
CERT Advisory:
CVE-ID(s):	CAN-2004-1305
NVD-ID(s):	CAN-2004-1305
US-CERT Technical Alerts:
Metric:	28.35
Document Revision:	48

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