Microsoft Internet Explorer Remote Code Execution Vulnerability

Date Published : 11 April 2006

Date Last Revised : 11 April 2006

Overview : A remote code execution vulnerability exists in Microsoft Internet Explorer. An attacker who successfully exploits this vulnerability could take complete control of an affected system.

This vulnerability has been classified as "High Risk." Computer users should take appropriate action to patch vulnerable systems.

Description : Several remote code execution vulnerabilities exist in Microsoft Internet Explorer.

A remote code execution vulnerability exists in the way Internet Explorer displays a Web page that contains certain unexpected method calls to HTML objects. As a result, system memory may be corrupted in such a way that an attacker could execute arbitrary code if a user visited a malicious Web site.

A remote code execution vulnerability exists in the way Internet Explorer handles multiple event handlers in an HTML element. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited the malicious Web site.

A remote code execution vulnerability exists in Internet Explorer. An HTML Application (HTA) can be initiated in a way that bypasses the security control within Internet Explorer. This allows an HTA to execute without Internet Explorer displaying the normal security dialog box. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited the malicious Web site.

A remote code execution vulnerability exists in the way Internet Explorer handles specially crafted and not valid HTML. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited the malicious Web site.

A remote code execution vulnerability exists in the way Internet Explorer instantiates COM objects that are not intended to be instantiated in Internet Explorer. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited the malicious Web site.

A remote code execution vulnerability exists in the way Internet Explorer handles HTML elements that contain a specially crafted tag. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited the malicious Web site.

A remote code execution vulnerability exists in the way Internet Explorer handles double-byte characters in specially crafted URLs. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited the malicious Web site.

A vulnerability exists in Internet Explorer in the way it returns IOleClientSite information when an embedded object is dynamically created. An attacker could exploit the vulnerability by constructing a malicious Web page with a dynamically created object. This object would need to make use of the IOleClientSite information returned to make a security related decision. This could potentially allow remote code execution or information disclosure if a user visited the malicious Web site.

An information disclosure vulnerability exists in Internet Explorer because of the way that it handles navigation methods. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially lead to information disclosure if a user visited a malicious Web site or viewed a specially crafted e-mail message.

A spoofing vulnerability exists in Internet Explorer that could allow an attacker to display spoofed content in a browser window. The address bar and other parts of the trust UI has been navigated away from the attacker's Web site but the content of the window still contains the attacker's Web page.

Impact : These vulnerability enables an attacker to execute code on the target system with elevated privileges.

In a Web-based attack scenario, an attacker could host a malicious Web site that is designed to exploit this vulnerability through Internet Explorer and then persuade a user to view the Web site. This can also include Web sites that accept user-provided content or advertisements, Web sites that host user-provided content or advertisements, and compromised Web sites. These Web sites could contain malicious content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to persuade users to visit the Web site, typically by getting them to click a link in an e-mail message or in an Instant Messenger request that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

An attacker could use the Address Bar Spoofing vulnerability to create a Web page that would display a URL of the attacker's choosing in the Address bar, while displaying a different Web site in the browser window. An attacker could use this vulnerability to create a malicious page that spoofs a legitimate site. However, it would not be possible to interact with this same Web site.

An attack that is successfully exploited would enable an attacker to install malicious code (worm, virus, Trojan horse), read confidential data, or take control over the target system.

Platforms Affected : Please review the Microsoft Security Bulletin MS06-013 for a complete list of affected platforms: http://www.microsoft.com/technet/security/bulletin/MS06-013.mspx

ZoneAlarm Products That Provide Protection : To ensure the most comprehensive protection, computer users should employ ZoneAlarm Security Suite, or ZoneAlarm Pro. Zone Labs products are not vulnerable to this attack. All Zone Labs security products, including ZoneAlarm, protect the user's system from unauthorized access and intrusions, and alert the user when malicious code attempts to access the network.

Recommended Actions :

ZoneAlarm Family

ZoneAlarm Pro and ZoneAlarm Security Suite protect your system against this vulnerability through "Internet Zone Security" and "Trusted Zone Security". It is recommended that you ensure the following:

• Internet Zone Security is set to High.
• Trusted Zone Security is set to Medium.
• Only trusted hosts are in the 'Trusted' Zone

Check Point Integrity

Check Point Integrity protects your system against this vulnerability through the following available services:

-Classic Firewall Rules

It is recommended that you ensure:

• Only trusted hosts are in the 'Trusted' Zone.

-SmartDefense Program Advisor

SmartDefense Program Advisor automatically blocks malware. It is recommended that you ensure the following:

• Internet Zone Security is set to High.
• Trusted Zone Security is set to Medium.

For more information about activating SmartDefense Program Advisor, please refer to CPSA-2005-10 .

-Advanced Cooperative Enforcement

• Use Advanced Cooperative Enforcement to enforce policy upon remote endpoints.

Related Resources :

Install Microsoft patches to remove this vulnerability from the Windows Operating System and other software components: http://windowsupdate.microsoft.com

Review Microsoft Security Bulletin MS06-013: http://www.microsoft.com/technet/security/bulletin/MS06-013.mspx

Contact : Zone Labs customers who are concerned about information contained in this advisory or have additional technical questions may reach Zone Labs Technical Support team at: http://www.zonelabs.com/store/content/support/support.jsp. To report security issues with Zone Labs products, contact security@zonelabs.com.

Disclaimer : The information in this advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.

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