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From:MICROSOFT <secure_(at)_microsoft.com>
Date:31.03.2010
Subject:Microsoft Security Bulletin MS10-018 - Critical Cumulative Security Update for Internet Explorer (980182)

Microsoft Security Bulletin MS10-018 - Critical
Cumulative Security Update for Internet Explorer (980182)
Published: March 30, 2010

Version: 1.0
General Information
Executive Summary

This security update resolves nine privately reported vulnerabilities and one publicly disclosed vulnerability in Internet Explorer. The most severe vulnerabilities could allow remote code execution if a user views a specially crafted Web page using Internet Explorer. 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.

This security update is rated Critical for all supported releases of Internet Explorer: Internet Explorer 5.01, Internet Explorer 6 Service Pack 1, Internet Explorer 6 on Windows clients, Internet Explorer 7, and Internet Explorer 8 on Windows clients. For Internet Explorer 6 on Windows servers, this update is rated Important. And for Internet Explorer 8 on Windows servers, this update is rated Moderate. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses these vulnerabilities by modifying the way that Internet Explorer verifies the origin of scripts and handles objects in memory, content using encoding strings, and long URL. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection under the next section, Vulnerability Information.

This security update also addresses the vulnerability first described in Microsoft Security Advisory 981374. The vulnerability, CVE-2010-0806, does not affect Windows 7, Windows Server 2008 R2, or Internet Explorer 8.

Recommendation. The majority of customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Known Issues. None
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Frequently Asked Questions (FAQ) Related to This Security Update

Where are the file information details?
The file information details can be found in the Microsoft Knowledge Base Article 980182.

Why does this update address several reported security vulnerabilities?
This update contains support for several vulnerabilities because the modifications that are required to address these issues are located in related files. Instead of having to install several updates that are almost the same, customers need to install this update only.

Does this update contain any security-related changes to functionality?
This update includes a defense-in-depth update to the X-XSS-Protection HTTP header. Specifically, a new "mode=block" syntax directs the XSS Filter to disable page content completely in the event that reflected cross-site scripting is detected. For example: X-XSS-Protection: 1; mode=block.

I have selected a default browser other than Internet Explorer. Do I still need to apply this update?
Internet Explorer provides application services and functionality for Windows and third-party programs that are maintained through the Cumulative Security Update for Internet Explorer. Microsoft recommends that customers apply the update immediately. The majority of customers have automatic updating enabled and will not need to take any action as this security update will be downloaded and installed automatically

I am using an older release of the software discussed in this security bulletin. What should I do?
The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, visit the Microsoft Support Lifecycle Web site.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. To determine the support lifecycle for your software release, see Select a Product for Lifecycle Information. For more information about service packs for these software releases, see Lifecycle Supported Service Packs.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, visit the Microsoft Worldwide Information Web site, select the country in the Contact Information list, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Microsoft Support Lifecycle Policy FAQ.
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Vulnerability Information

Severity Ratings and Vulnerability Identifiers

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the March bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Uninitialized Memory Corruption Vulnerability - CVE-2010-0267 Post Encoding Information Disclosure Vulnerability - CVE-2010-0488 Race Condition Memory Corruption Vulnerability - CVE-2010-0489 Uninitialized Memory Corruption Vulnerability - CVE-2010-0490 HTML Object Memory Corruption Vulnerability - CVE-2010-0491 HTML Object Memory Corruption Vulnerability - CVE-2010-0492 HTML Element Cross-Domain Vulnerability - CVE-2010-0494 Memory Corruption Vulnerability - CVE-2010-0805 Uninitialized Memory Corruption Vulnerability - CVE-2010-0806 HTML Rendering Memory Corruption Vulnerability - CVE-2010-0807 Aggregate Severity Rating
Internet Explorer 5.01 and Internet Explorer 6 Service Pack 1

Internet Explorer 5.01 Service Pack 4 when installed on Microsoft Windows 2000 Service Pack 4


Not applicable


Important
Information Disclosure


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Not applicable


Critical

Internet Explorer 6 Service Pack 1 when installed on Microsoft Windows 2000 Service Pack 4


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical
Internet Explorer 6

Internet Explorer 6 for Windows XP Service Pack 2 and Windows XP Service Pack 3


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 6 for Windows XP Professional x64 Edition Service Pack 2


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 6 for Windows Server 2003 Service Pack 2


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Not applicable


Important

Internet Explorer 6 for Windows Server 2003 x64 Edition Service Pack 2


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Not applicable


Important

Internet Explorer 6 for Windows Server 2003 with SP2 for Itanium-based Systems


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Not applicable


Important
Internet Explorer 7

Internet Explorer 7 for Windows XP Service Pack 2 and Windows XP Service Pack 3


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Not applicable


Important
Information Disclosure


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 for Windows XP Professional x64 Edition Service Pack 2


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Not applicable


Important
Information Disclosure


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 for Windows Server 2003 Service Pack 2


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 for Windows Server 2003 x64 Edition Service Pack 2


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 for Windows Server 2003 with SP2 for Itanium-based Systems


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 in Windows Vista, Windows Vista Service Pack 1, and Windows Vista Service Pack 2


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Not applicable


Important
Information Disclosure


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 in Windows Vista x64 Edition, Windows Vista x64 Edition Service Pack 1, and Windows Vista x64 Edition Service Pack 2


Critical
Remote Code Execution


Important
Information Disclosure


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Not applicable


Important
Information Disclosure


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 in Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2**


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 in Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2**


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Critical

Internet Explorer 7 in Windows Server 2008 for Itanium-based Systems and Windows Server 2008 for Itanium-based Systems Service Pack 2


Moderate
Remote Code Execution


Important
Information Disclosure


Moderate
Remote Code Execution


Moderate
Remote Code Execution


Not applicable


Not applicable


Low
Information Disclosure


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Critical
Internet Explorer 8

Internet Explorer 8 for Windows XP Service Pack 2 and Windows XP Service Pack 3


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Important
Information Disclosure


Not applicable


Not applicable


Not applicable


Critical

Internet Explorer 8 for Windows XP Professional x64 Edition Service Pack 2


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Important
Information Disclosure


Not applicable


Not applicable


Not applicable


Critical

Internet Explorer 8 for Windows Server 2003 Service Pack 2


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Not applicable


Moderate
Remote Code Execution


Low
Information Disclosure


Not applicable


Not applicable


Not applicable


Moderate

Internet Explorer 8 for Windows Server 2003 x64 Edition Service Pack 2


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Not applicable


Moderate
Remote Code Execution


Low
Information Disclosure


Not applicable


Not applicable


Not applicable


Moderate

Internet Explorer 8 in Windows Vista, Windows Vista Service Pack 1, and Windows Vista Service Pack 2


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Important
Information Disclosure


Not applicable


Not applicable


Not applicable


Critical

Internet Explorer 8 in Windows Vista x64 Edition, Windows Vista x64 Edition Service Pack 1, and Windows Vista x64 Edition Service Pack 2


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Important
Information Disclosure


Not applicable


Not applicable


Not applicable


Critical

Internet Explorer 8 in Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2**


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Not applicable


Moderate
Remote Code Execution


Low
Information Disclosure


Not applicable


Not applicable


Not applicable


Moderate

Internet Explorer 8 in Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2**


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Not applicable


Moderate
Remote Code Execution


Low
Information Disclosure


Not applicable


Not applicable


Not applicable


Moderate

Internet Explorer 8 in Windows 7 for 32-bit Systems


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Important
Information Disclosure


Not applicable


Not applicable


Not applicable


Critical

Internet Explorer 8 in Windows 7 for x64-based Systems


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Not applicable


Critical
Remote Code Execution


Important
Information Disclosure


Not applicable


Not applicable


Not applicable


Critical

Internet Explorer 8 in Windows Server 2008 R2 for x64-based Systems**


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Not applicable


Moderate
Remote Code Execution


Low
Information Disclosure


Not applicable


Not applicable


Not applicable


Moderate

Internet Explorer 8 in Windows Server 2008 R2 for Itanium-based Systems


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Not applicable


Moderate
Remote Code Execution


Low
Information Disclosure


Not applicable


Not applicable


Not applicable


Moderate

**Server Core installation not affected. The vulnerabilities addressed by this update do not affect supported editions of Windows Server 2008 or Windows Server 2008 R2 as indicated, when installed using the Server Core installation option. For more information on this installation option, see the MSDN articles, Server Core and Server Core for Windows Server 2008 R2. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008 and Windows Server 2008 R2; see Compare Server Core Installation Options.
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Uninitialized Memory Corruption Vulnerability - CVE-2010-0267

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that has not been correctly initialized or has been deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0267.

Mitigating Factors for Uninitialized Memory Corruption Vulnerability - CVE-2010-0267

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 5.01 Service Pack 4 and Internet Explorer 8 are not affected by this vulnerability.
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Workarounds for Uninitialized Memory Corruption Vulnerability - CVE-2010-0267

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Uninitialized Memory Corruption Vulnerability - CVE-2010-0267

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access an object that has not been initialized or has been deleted, it may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the logged-on user.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update addresses the vulnerability by modifying the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Post Encoding Information Disclosure Vulnerability - CVE-2010-0488

An information disclosure vulnerability exists in the way that Internet Explorer handles content using specific encoding strings when submitting data. An attacker could exploit the vulnerability by constructing a specially crafted Web page that could allow information disclosure if a user viewed the Web page. An attacker who successfully exploited this vulnerability could view content from the local computer or another browser window in another domain or Internet Explorer zone.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0488.

Mitigating Factors for Post Encoding Information Disclosure Vulnerability - CVE-2010-0488

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users to the attacker's Web site.


Internet Explorer 8 is not affected by this vulnerability.
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Workarounds for Post Encoding Information Disclosure Vulnerability - CVE-2010-0488

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Post Encoding Information Disclosure Vulnerability - CVE-2010-0488

What is the scope of the vulnerability?
This is an information disclosure vulnerability. An attacker who exploited the vulnerability when a user views a Web page could potentially view sensitive data stored in memory on the system.

What causes the vulnerability?
An information disclosure vulnerability exists in the way that Internet Explorer handles content using specific encoding strings when submitting data.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability when a user is viewing a Web page could potentially view sensitive data stored in memory on the system.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

What does the update do?
The update modifies the way that Internet Explorer handles content using specific encoding strings.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Race Condition Memory Corruption Vulnerability - CVE-2010-0489

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that may have been corrupted due to a race condition. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0489.

Mitigating Factors for Race Condition Memory Corruption Vulnerability - CVE-2010-0489

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 8 is not affected by this vulnerability.
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Workarounds for Race Condition Memory Corruption Vulnerability - CVE-2010-0489

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
Top of sectionTop of section

FAQ for Race Condition Memory Corruption Vulnerability - CVE-2010-0489

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access an object that may have been corrupted due to a race condition, it may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the logged-on user.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update modifies the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
Top of sectionTop of section
Top of sectionTop of section

Uninitialized Memory Corruption Vulnerability - CVE-2010-0490

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that has not been correctly initialized or has been deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0490.

Mitigating Factors for Uninitialized Memory Corruption Vulnerability - CVE-2010-0490

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 5.01 Service Pack 4 is not affected by this vulnerability.
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Workarounds for Uninitialized Memory Corruption Vulnerability - CVE-2010-0490

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
Top of sectionTop of section

FAQ for Uninitialized Memory Corruption Vulnerability - CVE-2010-0490

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access an object that has not been initialized or has been deleted, it may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the logged-on user.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update modifies the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
Top of sectionTop of section
Top of sectionTop of section

HTML Object Memory Corruption Vulnerability - CVE-2010-0491

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that has not been correctly initialized or has been deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0491.

Mitigating Factors for HTML Object Memory Corruption Vulnerability - CVE-2010-0491

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 7 and Internet Explorer 8 are not affected by this vulnerability.
Top of sectionTop of section

Workarounds for HTML Object Memory Corruption Vulnerability - CVE-2010-0491

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
Top of sectionTop of section

FAQ for HTML Object Memory Corruption Vulnerability - CVE-2010-0491

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access incorrectly initialized memory under certain conditions, it may corrupt memory in such a way that an attacker could execute arbitrary code.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update modifies the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
Top of sectionTop of section
Top of sectionTop of section

HTML Object Memory Corruption Vulnerability - CVE-2010-0492

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that has not been correctly initialized or has been deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0492.

Mitigating Factors for HTML Object Memory Corruption Vulnerability - CVE-2010-0492

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 6 and Internet Explorer 7 are not affected by this vulnerability.
Top of sectionTop of section

Workarounds for HTML Object Memory Corruption Vulnerability - CVE-2010-0492

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Modify the Access Control List (ACL) on mstime.dll

Modify the ACL to disable mstime.dll.

On Windows XP and Windows Server 2003, run the following command from an administrative command line:

Echo y| cacls %WINDIR%\SYSTEM32\mstime.DLL /E /P everyone:N

On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the following commands from an elevated command line:

Takeown.exe /f %WINDIR%\SYSTEM32\mstime.DLL
Icacls.exe %WINDIR%\SYSTEM32\mstime.DLL /save %TEMP%\mstime_ACL.TXT
Icacls.exe %WINDIR%\SYSTEM32\mstime.DLL /deny everyone:(F)

Impact of workaround. Functionality such as HTML and TIME are disabled.

How to undo the workaround.

On Windows XP and Windows Server 2003, run the following command from an administrative command line:

cacls %WINDIR%\SYSTEM32\mstime.dll /E /R everyone

On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the following commands from an elevated command line:

icacls %WINDIR%\SYSTEM32\mstime.DLL /grant everyone:(F)
icacls %WINDIR%\SYSTEM32 /restore %TEMP%\mstime_ACL.TXT



Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
Top of sectionTop of section

FAQ for HTML Object Memory Corruption Vulnerability - CVE-2010-0492

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access incorrectly initialized memory under certain conditions, it may corrupt memory in such a way that an attacker could execute arbitrary code.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update modifies the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
Top of sectionTop of section
Top of sectionTop of section

HTML Element Cross-Domain Vulnerability - CVE-2010-0494

An information disclosure vulnerability exists in Internet Explorer that could allow script to gain access to a browser window in another domain or Internet Explorer zone. An attacker could exploit the vulnerability by constructing a specially crafted Web page that could allow information disclosure if a user viewed the Web page and then drags the browser window across a second browser window.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0494.

Mitigating Factors for HTML Element Cross-Domain Vulnerability - CVE-2010-0494

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users to the attacker's Web site.


By default, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 5.01 Service Pack 4 is not affected by this vulnerability.
Top of sectionTop of section

Workarounds for HTML Element Cross-Domain Vulnerability - CVE-2010-0494

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for HTML Element Cross-Domain Vulnerability - CVE-2010-0494

What is the scope of the vulnerability?
This is an information disclosure vulnerability. An attacker who successfully exploited this vulnerability could execute script in the context of the user in another Internet Explorer domain. However, user interaction is required in order to exploit this vulnerability.

What causes the vulnerability?
Internet Explorer incorrectly interprets the origin of script, allowing the script to run in the context of a domain or Internet Explorer security zone other than where it originated.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could execute script in the context of the user in another Internet Explorer domain.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update enforces security checks when verifying the origin of the script.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Memory Corruption Vulnerability - CVE-2010-0805

A remote code execution vulnerability exists in the way that Internet Explorer manages a long URL in certain situations. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0805.

Mitigating Factors for Memory Corruption Vulnerability - CVE-2010-0805

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


Internet Explorer 7 and Internet Explorer 8 are not affected by this vulnerability.
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Workarounds for Memory Corruption Vulnerability - CVE-2010-0805

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Prevent COM objects from running in Internet Explorer

You can disable attempts to instantiate a COM object in Internet Explorer by setting the kill bit for the control in the registry.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

For detailed steps that you can use to prevent a control from running in Internet Explorer, see Microsoft Knowledge Base Article 240797. Follow the steps in this article to create a Compatibility Flags value in the registry to prevent a COM object from being instantiated in Internet Explorer.

To set the kill bit for a CLSID with a value of {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}, paste the following text in a text editor such as Notepad. Then, save the file by using the .reg file name extension.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{333C7BC4-460F-11D0-BC04-0080C7055A83}]
"Compatibility Flags"=dword:00000400

You can apply this .reg file to individual systems by double-clicking it. You can also apply it across domains by using Group Policy. For more information about Group Policy, visit the following Microsoft Web sites:


Group Policy collection


What is Group Policy Object Editor?


Core Group Policy tools and settings

Note You must restart Internet Explorer for your changes to take effect.

Impact of Workaround. There is no impact as long as the object is not intended to be used in Internet Explorer.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Memory Corruption Vulnerability - CVE-2010-0805

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
An ActiveX control in Internet Explorer incorrectly manages a long URL in certain situations. As a result, memory may be corrupted in such a way that an attacker could execute arbitrary code in the context of the logged-on user.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

What does the update do?
The update modifies the way that the ActiveX control in Internet Explorer manages long URL.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Uninitialized Memory Corruption Vulnerability - CVE-2010-0806

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that has not been correctly initialized or has been deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0806.

Mitigating Factors for Uninitialized Memory Corruption Vulnerability - CVE-2010-0806

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone, which disables script and ActiveX controls, removing the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.


Internet Explorer 5.01 Service Pack 4 and Internet Explorer 8 are not affected by this vulnerability.
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Workarounds for Uninitialized Memory Corruption Vulnerability - CVE-2010-0806

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Disable the peer factory class by editing the registry keys for iepeers.dll

First, create a backup copy of the registry keys by using the following command from an elevated command prompt:

Regedit.exe /e Disable_Peer_Factory_backup.reg HKEY_CLASSES_ROOT\CLSID\{3050F4CF-98B5-11CF-BB82-00AA00BDCE0B}

For Windows Vista and Windows Server 2008 only, you must first take ownership of [HKEY_CLASSES_ROOT\CLSID\{3050F4CF-98B5-11CF-BB82-00AA00BDCE0B}], as follows:

1.


As an administrator, click Start, click Run, type Regedit in the Open box, and then click OK

2.


Go to [HKEY_CLASSES_ROOT\CLSID\{3050F4CF-98B5-11CF-BB82-00AA00BDCE0B}]

3.


Click Permission, then Advanced, then Owner

4.


Change Owner to Administrator

5.


Click Grant Full Control to Administrator

6.


Iterate steps 3 through 5 for all subkeys

Next, save the following to a file with a .REG extension, such as Disable_Peer_Factory.reg:

Windows Registry Editor Version 5.00
[-HKEY_CLASSES_ROOT\CLSID\{3050F4CF-98B5-11CF-BB82-00AA00BDCE0B}]

Then run Disable_Peer_Factory.reg with the following command from an elevated command prompt:

Regedit.exe /s Disable_Peer_Factory.reg

Impact of workaround. Functionality that depends on peer factory, such as print and Web folders, may be affected.

How to undo the workaround.

Restore the original state by running the following command from an elevated command prompt:

Regedit.exe /s Disable_Peer_Factory_backup.reg



Modify the Access Control List (ACL) on iepeers.dll

To modify the ACL on iepeers.dll to be more restrictive, run the following commands from a command prompt with administrative privileges:

For 32-bit Windows systems:

Echo y| cacls %WINDIR%\SYSTEM32\iepeers.DLL /E /P everyone:N

For x64-based Windows systems:

Echo y| cacls %WINDIR%\SYSWOW64\iepeers.DLL /E /P everyone:N

Impact of workaround. Extended MSHTML functionality such as printing and Web folders may be affected.

How to undo the workaround.

Run the following commands from a command prompt with administrative privileges:

For 32-bit Windows Systems:

cacls %WINDIR%\SYSTEM32\iepeers.dll /E /R everyone

For x64-based Windows Systems:

cacls %WINDIR%\SYSWOW64\iepeers.dll /E /R everyone



Enable Data Execution Prevention (DEP) for Internet Explorer 7

Local Administrators can control DEP/NX by running Internet Explorer as an Administrator. To enable DEP, perform the following steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click Advanced.

2.


Click Enable memory protection to help mitigate online attacks.

Impact of workaround. Some browser extensions may not be compatible with DEP and may exit unexpectedly. If this occurs, you can disable the add-on, or revert the DEP setting using the Internet Control Panel. This is also accessible using the System Control panel.

How to undo the workaround.

Use the Internet Control Panel or the System Control Panel.


Enable DEP for Internet Explorer 7 using automated Microsoft Fix It

See Microsoft Knowledge Base Article 980182 to use the automated Microsoft Fix it solution to enable or disable this workaround.

Impact of workaround. Some browser extensions may not be compatible with DEP and may exit unexpectedly. If this occurs, you can disable the add-on, or revert the DEP setting using the Iautomated Microsoft Fix it solution to disable the workaround.


Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

To raise the browsing security level in Internet Explorer, follow these steps:

1.


On the Internet Explorer Tools menu, click Internet Options.

2.


In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

3.


Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

1.


In Internet Explorer, click Internet Options on the Tools menu.

2.


Click the Security tab.

3.


Click Internet, and then click Custom Level.

4.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

5.


Click Local intranet, and then click Custom Level.

6.


Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

7.


Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

Impact of workaround. There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

Add sites that you trust to the Internet Explorer Trusted sites zone

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

1.


In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

2.


In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

3.


If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

4.


In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

5.


Repeat these steps for each site that you want to add to the zone.

6.


Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Uninitialized Memory Corruption Vulnerability - CVE-2010-0806

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access an object that has not been initialized or has been deleted, it may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the logged-on user.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer for Windows Server 2003 or Windows Server 2008. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted Web content on a server. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone. See also Managing Internet Explorer Enhanced Security Configuration.

What does the update do?
The update modifies the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
Yes. This vulnerability has been publicly disclosed. It has been assigned Common Vulnerability and Exposure number CVE-2010-0806. It has also been described in Microsoft Security Advisory 981374.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
Yes. Microsoft is aware of attacks attempting to exploit the vulnerability.

If I applied workarounds provided in Advisory 981374, do I need to reverse them before applying this update?
If you applied workarounds provided in Microsoft Security Advisory 981374, you need to reverse them by following the instructions to undo the workaround provided in the subsection, Workarounds for Uninitialized Memory Corruption Vulnerability - CVE-2010-0806. If the iepeers.dll or DEP workarounds were applied using the "Enable this fix" feature provided in Microsoft Security Advisory 981374, you can reverse the workaround by selecting the "Disable this fix" option for these workarounds in Microsoft Knowledge Base Article 980182.
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HTML Rendering Memory Corruption Vulnerability - CVE-2010-0807

A remote code execution vulnerability exists in the way that Internet Explorer accesses an object that has been deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0807.

Mitigating Factors for HTML Rendering Memory Corruption Vulnerability - CVE-2010-0807

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:


In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted 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 convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users 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.


Internet Explorer 5.01 Service Pack 4, Internet Explorer 6, Internet Explorer 6 Service Pack 1, and Internet Explorer 8 are not affected by this vulnerability.
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Workarounds for HTML Rendering Memory Corruption Vulnerability - CVE-2010-0807

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:


Enable or disable ActiveX Controls in Office 2007

To reduce the possibility of this vulnerability being exploited through an Office 2007 document using an ActiveX control, follow the steps below to disable ActiveX controls within Office documents. For more information about disabling ActiveX controls in Office 2007, see the Microsoft Office Online article, Enable or disable ActiveX controls in Office documents.

Open the Trust Center in Office 2007 applications using one of the following methods. Once you have selected the ActiveX Settings, select Disable all controls without notification, and then click OK.

Note If you change an ActiveX control setting in one Office application, the settings are also changed in all the other Office programs on your computer.

Excel

Click the Microsoft Office button, select Excel Options, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

Outlook

From the Tools menu, select TrustCenter, select Trust Center Settings, and then select ActiveX Settings.

PowerPoint

Click the Microsoft Office button, select PowerPoint Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Word

Click the Microsoft Office button, select Word Options, select Trust Center, select TrustCenter Settings, and then select ActiveX Settings.

Access

Click the Microsoft Office button, select Access Options, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

InfoPath

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Publisher

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Visio

From the Tools menu, select Trust Center, select Trust Center Settings, and then select ActiveX Settings.

Impact of workaround. ActiveX controls will not be instantiated in Microsoft Office applications.


Do not open unexpected files

Do not open Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for HTML Rendering Memory Corruption Vulnerability - CVE-2010-0807

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
When Internet Explorer attempts to access an object that has been deleted, it may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the logged-on user.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as a logged-on user. If the user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the Web site. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by clicking a link in an e-mail message or in an Instant Messenger message that takes users to the attacker's Web site, or by opening an attachment sent through e-mail.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

What does the update do?
The update modifies the way that Internet Explorer handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Other Information
Acknowledgments

Microsoft thanks the following for working with us to help protect customers:


Secunia for working with us on the Uninitialized Memory Corruption Vulnerability (CVE-2010-0267)


Daiki Fukumori of Cyber Defense Institute Inc. for reporting the Post Encoding Information Disclosure Vulnerability (CVE-2010-0488)


Alexander Kornbrust of Red Database Security for reporting the Uninitialized Memory Corruption Vulnerability (CVE-2010-0490)


Ivan Fratric of iSIGHT Partners Global Vulnerability Partnership for reporting the Uninitialized Memory Corruption Vulnerability (CVE-2010-0490)


Wushi of team509, working with VeriSign iDefense Labs for reporting the HTML Object Memory Corruption Vulnerability (CVE-2010-0491)


Simon Zuckerbraun, working with TippingPoint's Zero Day Initiative for reporting the HTML Object Memory Corruption Vulnerability (CVE-2010-0492)


Paul Stone of Context Information Security for reporting the HTML Element Cross-Domain Vulnerability (CVE-2010-0494)


An anonymous researcher, working with TippingPoint's Zero Day Initiative for reporting the Memory Corruption Vulnerability (CVE-2010-0805)


ADLab of VenusTech for reporting the Uninitialized Memory Corruption Vulnerability (CVE-2010-0806)


ADLab of VenusTech for reporting the HTML Rendering Memory Corruption Vulnerability (CVE-2010-0807)

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please visit the active protections Web sites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.
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Support


Customers in the U.S. and Canada can receive technical support from Security Support or 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates. For more information about available support options, see Microsoft Help and Support.


International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

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