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From:MICROSOFT <secure_(at)_microsoft.com>
Date:10.12.2008
Subject:Microsoft Security Bulletin MS08-073 - Critical Cumulative Security Update for Internet Explorer (958215)

Microsoft Security Bulletin MS08-073 - Critical
Cumulative Security Update for Internet Explorer (958215)
Published: December 9, 2008

Version: 1.0
General Information
Executive Summary

This security update resolves four privately reported vulnerabilities. The 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 Internet Explorer 5.01 and Internet Explorer 6 Service Pack 1, running on Microsoft Windows 2000; Internet Explorer 6 running on Windows XP; and Internet Explorer 7. For Internet Explorer 6 running on Windows Server 2003, this security 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 validates parameters, handles the error resulting in the exploitable condition, and handles extra data when embedding objects in Web pages. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection under the next section, Vulnerability Information.

Recommendation. Microsoft recommends that customers apply the update immediately.

Known Issues. None
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Affected and Non-Affected Software

The software listed here have been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

Affected Software
Operating System Component Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by This Update
Internet Explorer 5.01 and Internet Explorer 6 Service Pack 1

Microsoft Windows 2000 Service Pack 4


Microsoft Internet Explorer 5.01 Service Pack 4


Remote Code Execution


Critical


MS08-058

Microsoft Windows 2000 Service Pack 4


Microsoft Internet Explorer 6 Service Pack 1


Remote Code Execution


Critical


MS08-058
Internet Explorer 6

Windows XP Service Pack 2 and Windows XP Service Pack 3


Microsoft Internet Explorer 6


Remote Code Execution


Critical


MS08-058

Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2


Microsoft Internet Explorer 6


Remote Code Execution


Critical


MS08-058

Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2


Microsoft Internet Explorer 6


Remote Code Execution


Moderate


MS08-058

Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2


Microsoft Internet Explorer 6


Remote Code Execution


Moderate


MS08-058

Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems


Microsoft Internet Explorer 6


Remote Code Execution


Moderate


MS08-058
Internet Explorer 7

Windows XP Service Pack 2 and Windows XP Service Pack 3


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Vista and Windows Vista Service Pack 1


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Server 2008 for 32-bit Systems*


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Server 2008 for x64-based Systems*


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

Windows Server 2008 for Itanium-based Systems


Windows Internet Explorer 7


Remote Code Execution


Critical


MS08-058

*Windows Server 2008 server core installation not affected. The vulnerabilities addressed by this update do not affect supported editions of Windows Server 2008 if Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; see Compare Server Core Installation Options.
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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 958215.

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. To determine the support life cycle for your software release, visit Microsoft Support Lifecycle.

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. For more information about the Windows Product Lifecycle, visit Microsoft Support Lifecycle. For more information about the extended security update support period for these software releases, visit the Microsoft Product Support Services Web site.

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, 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 Windows Operating System Product Support Lifecycle FAQ.
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Vulnerability Information

Severity Ratings and Vulnerability Identifiers
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Parameter Validation Memory Corruption Vulnerability - CVE-2008-4258 HTML Objects Memory Corruption Vulnerability - CVE-2008-4259 Uninitialized Memory Corruption Vulnerability - CVE-2008-4260 HTML Rendering Memory Corruption Vulnerability - CVE-2008-4261 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


Critical
Remote Code Execution


Not applicable


Not applicable


Critical
Remote Code Execution


Critical

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


Critical
Remote Code Execution


Not applicable


Not applicable


Critical
Remote Code Execution


Critical
Internet Explorer 6

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


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Critical

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


Not applicable


Not applicable


Not applicable


Critical
Remote Code Execution


Critical

Internet Explorer 6 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Moderate

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


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Moderate

Internet Explorer 6 for Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems


Not applicable


Not applicable


Not applicable


Moderate
Remote Code Execution


Moderate
Internet Explorer 7

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


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

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


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 7 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

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


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 7 for Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

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


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution



Not applicable


Critical

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


Not applicable


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 7 in Windows Server 2008 for 32-bit Systems*


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 7 in Windows Server 2008 for x64-based Systems*


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Internet Explorer 7 in Windows Server 2008 for Itanium-based Systems


Not applicable


Moderate
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

*Windows Server 2008 server core installation not affected. The vulnerabilities addressed by this update do not affect supported editions of Windows Server 2008 if Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; see Compare Server Core Installation Options.
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Parameter Validation Memory Corruption Vulnerability - CVE-2008-4258

A remote code execution vulnerability exists in the way Internet Explorer handles certain navigation methods. 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.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-4258.

Mitigating Factors for Parameter Validation Memory Corruption Vulnerability - CVE-2008-4258

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 and Microsoft Outlook Express open HTML e-mail messages in the Restricted sites zone. The Restricted sites zone helps mitigate attacks that could try to exploit this vulnerability by preventing Active Scripting and ActiveX controls from being used when reading HTML e-mail messages. However, 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 is not affected by this vulnerability.
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Workarounds for Parameter Validation Memory Corruption Vulnerability - CVE-2008-4258

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:


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_CLASSES_ROOT\CLSID\{EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B} = Shell.Explorer.1
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B}]
"Compatibility Flags"=dword:00000400

HKEY_CLASSES_ROOT\CLSID\{8856F961-340A-11D0-A96B-00C04FD705A2} = Shell.Explorer.2
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{8856F961-340A-11D0-A96B-00C04FD705A2}]
"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.

How to undo the workaround.

HKEY_CLASSES_ROOT\CLSID\{EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B} = Shell.Explorer.1
[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B}]

HKEY_CLASSES_ROOT\CLSID\{8856F961-340A-11D0-A96B-00C04FD705A2} = Shell.Explorer.2
[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{8856F961-340A-11D0-A96B-00C04FD705A2}]


Set Internet and Local intranet security zone settings to “High” to prompt before running 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 prompt before running 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 prompting before running 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. Prompting before running ActiveX Controls or 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 ActiveX Controls or 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.


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.
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FAQ for Parameter Validation Memory Corruption Vulnerability - CVE-2008-4258

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.

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. 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?
Internet Explorer does not properly validate parameters made during a method call in the browser. 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 the remote code execution 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.

How could an attacker exploit the vulnerability?
An attacker could host a specially crafted Web site that is designed to exploit the vulnerability through Internet Explorer and then convince a user to visit the Web site. 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 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 in an Instant Messenger message that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability?
A user must be logged on and visiting a Web site for malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations and 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 validates parameters during specific method calls.

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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HTML Objects Memory Corruption Vulnerability - CVE-2008-4259

A remote code execution vulnerability exists in Internet Explorer due to attempts to access uninitialized memory 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.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-4259.

Mitigating Factors for HTML Objects Memory Corruption Vulnerability - CVE-2008-4259

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 and Microsoft Outlook Express open HTML e-mail messages in the Restricted sites zone. The Restricted sites zone helps mitigate attacks that could try to exploit this vulnerability by preventing Active Scripting and ActiveX controls from being used when reading HTML e-mail messages. However, 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.


Microsoft Internet Explorer 6 is not affected by this vulnerability.
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Workarounds for HTML Objects Memory Corruption Vulnerability - CVE-2008-4259

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:


Disable the WebClientservice

To disable the WebClient Service by command line, perform the following steps:

1.


Click Start, click Run, type Services.msc and then click OK.

2.


Right-click WebClientservice and select Properties.

3.


Change the Startup type to Disabled. If the service is running, click Stop.

4.


Click OK and exit the management application.

Impact of workaround. WebDAV shares will be inaccessible.

How to undo the workaround.

To re-enable the WebDAV Service by command line, follow these steps:

1.


Click Start, click Run, type Services.msc and then click OK.

2.


Right-click WebClientservice and select Properties.

3.


Change the Startup type to Automatic and click Apply.

4.


Click Start and then click OK and exit the management application.
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FAQ for HTML Objects Memory Corruption Vulnerability - CVE-2008-4259

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. 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. 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 uninitialized memory in certain situations, 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 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.

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. 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 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 in an Instant Messenger message that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability?
A user must be logged on and visiting a Web site for malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations and 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 the error when attempting to access uninitialized 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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Uninitialized Memory Corruption Vulnerability – CVE-2008-4260

A remote code execution vulnerability exists in the way 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.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-4260.

Mitigating Factors for Uninitialized Memory Corruption Vulnerability – CVE-2008-4260

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 and Microsoft Outlook Express open HTML e-mail messages in the Restricted sites zone. The Restricted sites zone helps mitigate attacks that could try to exploit this vulnerability by preventing Active Scripting and ActiveX controls from being used when reading HTML e-mail messages. However, 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.


Microsoft Internet Explorer 6 is not affected by this vulnerability.
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Workarounds for Uninitialized Memory Corruption Vulnerability – CVE-2008-4260

Microsoft has not identified any workarounds for this vulnerability.
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FAQ for Uninitialized Memory Corruption Vulnerability – CVE-2008-4260

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.

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. 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?
Internet Explorer attempts to access an object that has been deleted. 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 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.

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. 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 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 in an Instant Messenger message that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visit 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 errors when calls are made to objects that have been deleted.

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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HTML Rendering Memory Corruption Vulnerability - CVE-2008-4261

A remote code execution vulnerability exists in the way Internet Explorer embeds objects into a Web page. 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.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-4261.

Mitigating Factors for HTML Rendering Memory Corruption Vulnerability - CVE-2008-4261

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, 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.


Windows XP Service Pack 2 introduced a security enhancement known as the Local Machine Zone Lockdown. This security enhancement mitigates this vulnerability when the Local Machine Zone is the target of an attack. This feature restricts HTML in the Local Machine zone. This feature also restricts HTML that is hosted in Internet Explorer. These restrictions help mitigate attacks where the Local Machine zone is used as an attack vector to load malicious HTML code. Because of this change, ActiveX script in local HTML pages that are viewed inside Internet Explorer will not run. Also, script in local HTML pages that is viewed inside Internet Explorer prompts the user for permission to run.


Internet Explorer 7 is not affected by this vulnerability.
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Workarounds for HTML Rendering Memory Corruption Vulnerability - CVE-2008-4261

Microsoft has not identified any workarounds for this vulnerability.
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FAQ for HTML Rendering Memory Corruption Vulnerability - CVE-2008-4261

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.

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. 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 displays a Web page that contains unexpected data while embedding an object into the page, memory may be corrupted 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 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.

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 visit the Web site. This could also include 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 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 in an Instant Messenger message that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability?
A user be logged on and visiting a Web site for 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 extra data while embedding objects.

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:


Carlo Di Dato (aka shinnai) for reporting the Parameter Validation Memory Corruption Vulnerability (CVE-2008-4258)


Brett Moore, working with TippingPoint and the Zero Day Initiative, for reporting the HTML Objects Memory Corruption Vulnerability (CVE-2008-4259)


Chris Weber of Casaba Security for reporting the Uninitialized Memory Corruption Vulnerability (CVE-2008-4260)


Jun Mao of Verisign iDefense Labs for reporting the HTML Rendering Memory Corruption Vulnerability (CVE-2008-4261)
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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.

Support


Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.


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.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions


V1.0 (December 9, 2008): Bulletin published.

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