Thursday, September 28, 2006

Microsoft Security Advisory 926043

The details of the advisory are below. The work-around, as always, keep your antivirus software updated and don't open unexpected attachments in e-mails. For this vulnerability, at least until the Windows Update on October 10, when using Internet Explorer, disable Active X.

To disable Active X:

-- Click Tools > Internet Options > Security tab > Internet Web Content Zone > Custom Level
-- In the Settings box, scroll to "Scripting" and Disable Active scripting and Scripting of Java applets.
-- Click OK twice.

This alert is to notify you that Microsoft has released Security Advisory 926043 – Vulnerability in Windows Shell Could Allow Remote Code Execution - on 28 September 2006.


Microsoft is investigating new public reports of a vulnerability in supported versions of Microsoft Windows. Customers who are running Windows Server 2003 and Windows Server 2003 Service Pack 1 in their default configurations, with the Enhanced Security Configuration turned on, are not affected. We are also aware of proof of concept code published publicly. We are not aware of any attacks attempting to use the reported vulnerability or of customer impact at this time. We will continue to investigate these public reports.

The ActiveX control called out in the public reports and in the Proof of Concept code is the Microsoft WebViewFolderIcon ActiveX control (Web View). The vulnerability exists in Windows Shell and is exposed by Web View.

We are working on a security update currently scheduled for an October 10 release.

Customers are encouraged to keep their anti-virus software up to date.

Microsoft encourages users to exercise caution when they open e-mail and links in e-mail from untrusted sources. For more information about Safe Browsing, visit the Trustworthy Computing Web site.

Mitigating Factors
• In a Web-based attack scenario, an attacker would have to host a Web site that contains a Web page that is used to exploit this vulnerability. An attacker would have no way to force users to visit a malicious Web site. Instead, an attacker would have to persuade them to visit the Web site, typically by getting them to click a link that takes them to the attacker's Web site.
• An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
• By default, Outlook Express 6, Outlook 2002, and Outlook 2003 open HTML e-mail messages in the Restricted sites zone. Additionally, Outlook 2000 opens HTML e-mail messages in the Restricted sites zone if the Outlook E-mail Security Update has been installed. Outlook Express 5.5 Service Pack 2 opens HTML e-mail messages in the Restricted sites zone if Microsoft Security Bulletin MS04-018 has been installed.
• By default, Internet Explorer on Windows Server 2003 runs in a restricted mode that is known as Enhanced Security Configuration. This mode mitigates this vulnerability because ActiveX and Active Scripting are disabled by default.

Additional Resources:

• Microsoft Security Advisory 926043 – Vulnerability in Windows Shell Could Allow Remote Code Execution

• MSRC Blog:

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