Microsoft Security Advisory (927892)

Microsoft Security Advisory (927892)
Vulnerability in Microsoft XML Core Services Could Allow Remote Code Execution
Published: November 3, 2006

Microsoft is investigating public reports of a vulnerability in the XMLHTTP 4.0 ActiveX Control, part of Microsoft XML Core Services 4.0 on Windows. We are aware of limited attacks that are attempting to use the reported vulnerability.

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. Customers would need to visit an attacker’s Web site to be at risk. We will continue to investigate these public reports.

Upon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. A security update will be released through our monthly release process or an out-of-cycle security update will be provided, depending on customer needs.

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.

We continue to encourage customers to follow our Protect Your PC guidance of enabling a firewall, applying software updates and installing antivirus software. Customers can learn more about these steps at the Protect Your PC Web site.

Customers who believe they have been attacked should contact their local FBI office or post their complaint on the Internet Fraud Complaint Center Web site. Customers outside the U.S. should contact the national law enforcement agency in their country.

Customers who believe they may have been affected by this issue can also contact Product Support Services. You can contact Product Support Services in the United States and Canada at no charge using the PC Safety line (1 866-PCSAFETY). Customers outside of the United States and Canada can locate the number for no-charge virus support by visiting the Microsoft Help and Support 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 logged on 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.

• The Restricted sites zone helps reduce attacks that could try to exploit this vulnerability by preventing Active Scripting from being used when reading HTML e-mail messages. However, if a user clicks a link in an e-mail message, they could still be vulnerable to this issue through the Web-based attack scenario.

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.

http://www.microsoft.com/technet/security/...ory/927892.mspx