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Cumulative Security Update for Internet Explorer (MS07-016)
------------------------------------------------------------------------
SUMMARY
This update resolves two newly discovered, publicly and privately reported
vulnerabilities in Internet Explorer.
DETAILS
Affected Software:
* Microsoft Windows 2000 Service Pack 4
* Microsoft Windows XP Service Pack 2
* Microsoft Windows XP Professional x64 Edition
* Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service
Pack 1
* Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft
Windows Server 2003 with SP1 for Itanium-based Systems
* Microsoft Windows Server 2003 x64 Edition
Non-Affected Software:
* Windows Vista
Tested Microsoft Windows Components:
Affected Components:
* Microsoft Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service
Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=2D83EFCE-E507-4AFF-AB9B-EAF1D0D6320D>
Download the update
* Microsoft Internet Explorer 6 Service Pack 1 when installed on Windows
2000 Service Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=D9E4181A-05F9-4186-BDCA-C95351983844>
Download the update
* Microsoft Internet Explorer 6 for Windows XP Service Pack 2 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=D4038DC1-8AF6-4BEA-82B8-EACCFF4CDB28>
Download the update
* Microsoft Internet Explorer 6 for Windows XP Professional x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=D6EEEA2C-785E-4DEF-913E-7F121556554F>
Download the update
* Microsoft Internet Explorer 6 for Windows Server 2003 and Microsoft
Windows Server 2003 Service Pack 1 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=C6BCBE07-39C1-4705-A10D-019DA3F997E5>
Download the update
* Microsoft Internet Explorer 6 for Windows Server 2003 for Itanium-based
Systems and Windows Server 2003 with SP1 for Itanium-based Systems -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=6476A14B-0D00-4F55-A438-E140E9D26849>
Download the update
* Microsoft Internet Explorer 6 for Windows Server 2003 x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=C18DB204-0F2C-4DD4-B29C-0938FF1BFD7B>
Download the update
* Windows Internet Explorer 7 for Windows XP Service Pack 2 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=EE851EFD-2CAF-41CE-A423-E1827DE318DF>
Download the update
* Windows Internet Explorer 7 for Windows XP Professional x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=AC084BBB-084D-47AC-BFDA-156E34A63817>
Download the update
* Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=36DAE010-AD1F-4E77-A353-9AFA41F065EA>
Download the update
* Windows Internet Explorer 7 for Windows Server 2003 with SP1 for
Itanium-based Systems -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=631B590D-98CE-440D-B588-88CC31BB9370>
Download the update
* Windows Internet Explorer 7 for Windows Server 2003 x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=A05D1E57-6678-4C25-B5E2-98F18BAA454B>
Download the update
Non-Affected Components:
* Windows Internet Explorer 7 in Windows Vista
COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697:
A remote code execution vulnerability exists in the way Internet Explorer
instantiates COM objects that are not intended to be instantiated in
Internet Explorer. An attacker could exploit the vulnerability by
constructing a specially crafted Web page that could potentially allow
remote code execution if a user viewed the Web page. An attacker who
successfully exploited this vulnerability could take complete control of
an affected system.
Mitigating Factors for COM Object Instantiation Memory Corruption
Vulnerability - CVE-2006-4697:
* 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, Web sites that accept or host user-provided content, or
compromised Web sites and advertisement servers could contain specially
crafted content that could exploit this vulnerability. Instead, an
attacker would have to persuade users to visit the Web site, typically by
getting them to click a link in an e-mail message or 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 reduce the number of successful attacks
that exploit this vulnerability by preventing Active Scripting and ActiveX
controls from being used when reading HTML e-mail. However, if a user
clicks on a link within an e-mail, they could still be vulnerable to this
issue through the Web-based attack scenario.
* By default, Internet Explorer on Windows Server 2003 runs in a
restricted mode that is known as
<http://msdn.microsoft.com/library/default.asp?url=/workshop/security/szone/overview/esc_changes.asp>
Enhanced Security Configuration. This mode sets the security level for the
Internet zone to High. This is a mitigating factor for Web sites that have not
been added to Internet Explorer Trusted sites zone. See the FAQ subsection of
this vulnerability section for more information about Internet Explorer
Enhanced Security Configuration.
* COM Objects not intended to be instantiated in Internet Explorer are
not included in the default allow-list for ActiveX controls in Windows
Internet Explorer 7. Customers who are running Windows Internet Explorer 7
with default settings are therefore not at risk unless these COM Objects
have been activated through the ActiveX opt-in feature in the Internet
Zone. Customers who are upgrading to Windows Internet Explorer 7 and have
enabled these COM objects in previous versions of Internet Explorer will
have them enabled in Windows Internet Explorer 7. For more information on
the
<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ietechcol/cols/dnexpie/activex_security.asp>
ActiveX Opt-in feature and how to add ActiveX controls to the pre-approved
list, see the
<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ietechcol/cols/dnexpie/activex_security.asp>
product documentation.
* Windows Internet Explorer 7 in Windows Vista is not affected by this
vulnerability.
Workarounds for COM Object Instantiation Memory Corruption Vulnerability -
CVE-2006-4697:
Microsoft has tested the following workarounds. While these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.
* Configure Internet Explorer to prompt before running ActiveX Controls
or disable ActiveX Controls in the Internet and Local intranet security
zone
You can help protect against this vulnerability by changing your Internet
Explorer settings to prompt before running ActiveX controls. 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 ActiveX controls and plug-ins section, under Run
ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.
5. Click Local intranet, and then click Custom Level.
6. Under Settings, in the ActiveX controls and plug-ins section, under Run
ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.
7. Click OK two times to return to Internet Explorer.
Impact of Workaround: There are side effects to prompting before running
ActiveX controls. Many Web sites that are on the Internet or on an
intranet use ActiveX 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 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. 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
computer. Two in particular that you may want to add are
"*.windowsupdate.microsoft.com" and *.update.microsoft.com (without the
quotation marks). These are the sites that will host the update, and it
requires an ActiveX Control to install the update.
* 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 this vulnerability by changing your settings
for the Internet security zone to prompt before running ActiveX controls.
You can do this by setting your browser security to High.
To raise the browsing security level in Microsoft 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. Many Web sites that are on the Internet or on an
intranet use ActiveX 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 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. 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
computer. Two in particular that you may want to add are
"*.windowsupdate.microsoft.com" and *.update.microsoft.com (without the
quotation marks). These are the sites that will host the update, and it
requires an ActiveX Control to install the update.
* 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 <http://support.microsoft.com/kb/240797> Microsoft
Knowledge Base Article 240797. Follow these 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\{ XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX }]
"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:
<http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/6d7cb788-b31d-4d17-9f1e-b5ddaa6deecd.mspx>
Group Policy collection
<http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/47ba1311-6cca-414f-98c9-2d7f99fca8a3.mspx>
What is Group Policy Object Editor?
<http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/e926577a-5619-4912-b5d9-e73d4bdc9491.mspx>
Core Group Policy tools and settings
Note You must restart Internet Explorer for your changes to take effect.
The Class Identifiers and corresponding files where the COM objects are
contained are documented under What does the update do? in the FAQ for
COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697
section.
Impact of Workaround: There is no impact as long as the COM object is not
intended to be used in Internet Explorer.
FAQ for COM Object Instantiation Memory Corruption Vulnerability -
CVE-2006-4697:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who
successfully exploited this vulnerability could remotely 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.
What causes the vulnerability?
When Internet Explorer tries to instantiate certain COM objects as ActiveX
controls, the COM objects may corrupt the system state 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 persuade a
user to view the Web site. This can also include Web sites that accept
user-provided content or advertisements, Web sites that host user-provided
content or advertisements, and compromised Web sites. These Web sites
could contain 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
persuade users to visit the Web site, typically by getting them to click a
link in an e-mail message or in an Instant Messenger request that takes
users to the attacker's Web site. It could also be possible to display
specially crafted Web content by using banner advertisements or by using
other methods to deliver Web content to affected systems.
What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user is logged on and visits 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 Windows Internet Explorer 7. Does this mitigate this
vulnerability?
Yes. Customers who are running Windows Internet Explorer 7 with default
settings, are not at risk unless these COM Objects have been activated
through the ActiveX opt-in feature in the Internet Zone. Customers who are
upgrading to Windows Internet Explorer 7 and have enabled these COM
objects in previous versions of Internet Explorer will have them enabled
in Windows Internet Explorer 7. For more information on the ActiveX Opt-in
feature and how to add ActiveX controls to the pre-approved list, see the
<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ietechcol/cols/dnexpie/activex_security.asp>
product documentation.
Windows Internet Explorer 7 in Windows Vista is not affected by this
vulnerability.
What is the ActiveX opt-in feature in Windows Internet Explorer 7?
Windows Internet Explorer 7 includes an ActiveX opt-in feature, which
means that nearly all pre-installed ActiveX controls are off by default.
Users are prompted by the Information Bar before they can instantiate a
previously installed ActiveX control that has not yet been used on the
Internet. This enables a user to permit or deny access on a
control-by-control basis. For more information about this and other new
features, see the
<http://www.microsoft.com/windows/ie/ie7/about/features/default.mspx>
Windows Internet Explorer 7 features page.
I am running Internet Explorer on Windows Server 2003. Does this mitigate
this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 runs in a
restricted mode that is known as
<http://msdn.microsoft.com/library/default.asp?url=/workshop/security/szone/overview/esc_changes.asp>
Enhanced Security Configuration. This mode sets the security level for the
Internet zone to High. This is a mitigating factor for Web sites that have not
been added to Internet Explorer Trusted sites zone. See the next FAQ in this
section for more information about Internet Explorer Enhanced Security
Configuration.
What is Internet Explorer Enhanced Security Configuration?
Internet Explorer Enhanced Security Configuration is a group of
preconfigured Internet Explorer settings that reduce the likelihood of a
user or administrator downloading and running malicious Web content on a
server. Internet Explorer Enhanced Security Configuration reduces this
threat by modifying numerous security-related settings, including Security
and Advanced tab settings in Internet Options. Some of the key
modifications include:
* Security level for the Internet zone is set to High. This setting
disables scripts, ActiveX components, Microsoft virtual machine (Microsoft
VM) HTML content, and file downloads.
* Automatic detection of intranet sites is disabled. This setting assigns
all intranet Web sites and all Universal Naming Convention (UNC) paths
that are not explicitly listed in the Local intranet zone to the Internet
zone.
* Install on Demand and non-Microsoft browser extensions are disabled.
This setting prevents Web pages from automatically installing components
and prevents non-Microsoft extensions from running.
* Multimedia content is disabled. This setting prevents music,
animations, and video clips from running.
For more information regarding Internet Explorer Enhanced Security
Configuration, please consult the Managing Internet Explorer Enhanced
Security Configuration guide, which can be found at the following
<http://www.microsoft.com/downloads/details.aspx?FamilyID=d41b036c-e2e1-4960-99bb-9757f7e9e31b&DisplayLang=en>
Web site.
What does the update do?
Because not all COM objects are designed to be accessed through Internet
Explorer, this update sets the <http://support.microsoft.com/kb/240797>
kill bit for a list of Class Identifiers (CLSIDs) for COM objects that
have been found to exhibit similar behavior to the COM Object
Instantiation Memory Corruption Vulnerability that is addressed in
<http://go.microsoft.com/fwlink/?LinkId=53511> Microsoft Security Bulletin
MS05-054. To help protect customers, this update prevents these CLSIDs
from being instantiated in Internet Explorer. For more information about
kill bits, see <http://support.microsoft.com/kb/240797> Microsoft
Knowledge Base Article 240797.
The Class Identifiers and corresponding files where the COM objects are
contained are as follows:
DA56F851-D3C5-11D3-844C-00C04F7A06E5 - Imjpcksid.dll
6E3197A3-BBC3-11D4-84C0-00C04F7A06E5 - Imjpskdic.dll
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-2006-4697.
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.
COM Object Instantiation Memory Corruption Vulnerability - CVE-2007-0219:
A remote code execution vulnerability exists in the way Internet Explorer
instantiates COM objects that are not intended to be instantiated in
Internet Explorer. An attacker could exploit the vulnerability by
constructing a specially crafted Web page that could potentially allow
remote code execution if a user viewed the Web page. An attacker who
successfully exploited this vulnerability could take complete control of
an affected system.
Mitigating Factors for COM Object Instantiation Memory Corruption
Vulnerability - CVE-2007-0219:
* 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, Web sites that accept or host user-provided content or
compromised Web sites and advertisement servers could contain specially
crafted content that could exploit this vulnerability. Instead, an
attacker would have to persuade users to visit the Web site, typically by
getting them to click a link in an e-mail message or 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 reduce the number of successful attacks
that exploit this vulnerability by preventing Active Scripting and ActiveX
controls from being used when reading HTML e-mail. However, if a user
clicks on a link within an e-mail they could still be vulnerable to this
issue through the Web-based attack scenario.
* By default, Internet Explorer on Windows Server 2003 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 have not been added to Internet
Explorer Trusted sites zone. See the FAQ subsection of this vulnerability
section for more information about Internet Explorer Enhanced Security
Configuration.
* COM Objects not intended to be instantiated in Internet Explorer are
not included in the default allow-list for ActiveX controls in Windows
Internet Explorer 7. Customers who are running Windows Internet Explorer 7
with default settings, are therefore not at risk unless these COM Objects
have been activated through the ActiveX opt-in feature in the Internet
Zone. Customers who are upgrading to Windows Internet Explorer 7 and have
enabled these COM objects in previous versions of Internet Explorer will
have them enabled in Windows Internet Explorer 7. For more information on
the ActiveX Opt-in feature and how to add ActiveX controls to the
pre-approved list, see the product documentation.
* Windows Internet Explorer 7 in Windows Vista is not affected by this
vulnerability.
Workarounds for COM Object Instantiation Memory Corruption Vulnerability -
CVE-2007-0219:
Microsoft has tested the following workarounds. While these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.
Configure Internet Explorer to prompt before running ActiveX Controls or
disable ActiveX Controls in the Internet and Local intranet security zone
You can help protect against this vulnerability by changing your Internet
Explorer settings to prompt before running ActiveX controls. 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 ActiveX controls and plug-ins section, under Run
ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.
5. Click Local intranet, and then click Custom Level.
6. Under Settings, in the ActiveX controls and plug-ins section, under Run
ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.
7. Click OK two times to return to Internet Explorer.
Impact of Workaround: There are side effects to prompting before running
ActiveX controls. Many Web sites that are on the Internet or on an
intranet use ActiveX 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 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. 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
computer. Two in particular that you may want to add are
"*.windowsupdate.microsoft.com" and *.update.microsoft.com (without the
quotation marks). These are the sites that will host the update, and it
requires an ActiveX Control to install the update.
* 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 this vulnerability by changing your settings
for the Internet security zone to prompt before running ActiveX controls.
You can do this by setting your browser security to High.
To raise the browsing security level in Microsoft 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. Many Web sites that are on the Internet or on an
intranet use ActiveX 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 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. 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
computer. Two in particular that you may want to add are
"*.windowsupdate.microsoft.com" and *.update.microsoft.com (without the
quotation marks). These are the sites that will host the update, and it
requires an ActiveX Control to install the update.
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
these 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\{ XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX }]
"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:
<http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/6d7cb788-b31d-4d17-9f1e-b5ddaa6deecd.mspx>
Group Policy collection
<http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/47ba1311-6cca-414f-98c9-2d7f99fca8a3.mspx>
What is Group Policy Object Editor?
<http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/e926577a-5619-4912-b5d9-e73d4bdc9491.mspx>
Core Group Policy tools and settings
Note You must restart Internet Explorer for your changes to take effect.
The Class Identifiers and corresponding files where the COM objects are
contained are documented under What does the update do? in the FAQ for
COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697
section.
Impact of Workaround: There is no impact as long as the COM object is not
intended to be used in Internet Explorer.
FAQ for COM Object Instantiation Memory Corruption Vulnerability -
CVE-2007-0219:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who
successfully exploited this vulnerability could remotely 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.
What causes the vulnerability?
When Internet Explorer tries to instantiate certain COM objects as ActiveX
controls, the COM objects may corrupt the system state 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 persuade a
user to view the Web site. This can also include Web sites that accept
user-provided content or advertisements, Web sites that host user-provided
content or advertisements, and compromised Web sites. These Web sites
could contain 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
persuade users to visit the Web site, typically by getting them to click a
link in an e-mail message or in an Instant Messenger request that takes
users to the attacker's Web site. It could also be possible to display
specially crafted Web content by using banner advertisements or by using
other methods to deliver Web content to affected systems.
What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user is logged on and visits 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 Windows Internet Explorer 7. Does this mitigate this
vulnerability?
Yes. Customers who are running Windows Internet Explorer 7 with default
settings, are not at risk unless these COM Objects have been activated
through the ActiveX opt-in feature in the Internet Zone. Customers who are
upgrading to Windows Internet Explorer 7 and have enabled these COM
objects in previous versions of Internet Explorer will have them enabled
in Windows Internet Explorer 7. For more information on the ActiveX Opt-in
feature and how to add ActiveX controls to the pre-approved list, see the
product documentation.
Windows Internet Explorer 7 in Windows Vista is not affected by this
vulnerability.
What is the ActiveX opt-in feature in Windows Internet Explorer 7?
Windows Internet Explorer 7 includes an ActiveX opt-in feature, which
means that nearly all pre-installed ActiveX controls are off by default.
Users are prompted by the Information Bar before they can instantiate a
previously installed ActiveX control that has not yet been used on the
Internet. This enables a user to permit or deny access on a
control-by-control basis. For more information about this and other new
features, see the Windows Internet Explorer 7 features page.
I am running Internet Explorer on Windows Server 2003. Does this mitigate
this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 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 have not been added to Internet
Explorer Trusted sites zone. See the next FAQ in this section for more
information about Internet Explorer Enhanced Security Configuration.
What is Internet Explorer Enhanced Security Configuration?
Internet Explorer Enhanced Security Configuration is a group of
preconfigured Internet Explorer settings that reduce the likelihood of a
user or administrator downloading and running malicious Web content on a
server. Internet Explorer Enhanced Security Configuration reduces this
threat by modifying numerous security-related settings, including Security
and Advanced tab settings in Internet Options. Some of the key
modifications include:
* Security level for the Internet zone is set to High. This setting
disables scripts, ActiveX components, Microsoft virtual machine (Microsoft
VM) HTML content, and file downloads.
* Automatic detection of intranet sites is disabled. This setting assigns
all intranet Web sites and all Universal Naming Convention (UNC) paths
that are not explicitly listed in the Local intranet zone to the Internet
zone.
* Install on Demand and non-Microsoft browser extensions are disabled.
This setting prevents Web pages from automatically installing components
and prevents non-Microsoft extensions from running.
* Multimedia content is disabled. This setting prevents music,
animations, and video clips from running.
For more information regarding Internet Explorer Enhanced Security
Configuration, please consult the Managing Internet Explorer Enhanced
Security Configuration guide, which can be found at the following
<http://www.microsoft.com/downloads/details.aspx?FamilyID=d41b036c-e2e1-4960-99bb-9757f7e9e31b&DisplayLang=en>
Web site.
What does the update do?
Because not all COM objects are designed to be accessed through Internet
Explorer, this update sets the kill bit for a list of Class Identifiers
(CLSIDs) for COM objects that have been found to exhibit similar behavior
to the COM Object Instantiation Memory Corruption Vulnerability that is
addressed in Microsoft Security Bulletin MS05-054. To help protect
customers, this update prevents these CLSIDs from being instantiated in
Internet Explorer. For more information about kill bits, see Microsoft
Knowledge Base Article 240797.
The Class Identifiers and corresponding files where the COM objects are
contained are as follows:
75C11604-5C51-48B2-B786-DF5E51D10EC9 Msb1fren.dll
8422DAE3-9929-11CF-B8D3-004033373DA8 Htmlmm.ocx
8422DAE7-9929-11CF-B8D3-004033373DA8 Htmlmm.ocx
261F6572-578B-40A7-B72E-61B7261D9F0C Blnmgrps.dll
E56CCB42-598C-462D-9AD8-4FD5B4498C5D Blnmgrps.dll
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.
FTP Server Response Parsing Memory Corruption Vulnerability -
CVE-2007-0217:
A remote code execution vulnerability exists in the way Internet Explorer
interprets certain responses from FTP servers. An attacker could exploit
the vulnerability by sending specially crafted FTP responses in an FTP
session to the FTP client included in Internet Explorer. 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.
Mitigating Factors for FTP Server Response Parsing Memory Corruption
Vulnerability - CVE-2007-0217:
* In a Web-based attack scenario, an attacker would have to host an FTP
server that would return these specially crafted FTP server responses to
exploit this vulnerability. An attacker would have no way to force users
to visit the site with the FTP server. Instead, an attacker would have to
persuade them to visit the site, typically by getting them to click a link
in an e-mail message or Instant Messenger message that takes them to the
attacker's 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 reduce attacks that could try to exploit
this vulnerability by preventing Active Scripting and ActiveX controls
from being used when reading HTML e-mail. However, if a user clicks on a
link within an e-mail they could still be vulnerable to this issue through
the Web-based attack scenario.
Note It cannot be ruled out that this vulnerability could be used in an
exploit without Active Scripting. However, using Active Scripting
significantly increases the chances of a successful exploit. As a result,
this vulnerability has been given a severity rating of Critical on Windows
Server 2003.
* By default, Internet Explorer on Windows Server 2003 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 have not been added to Internet
Explorer Trusted sites zone. See the FAQ subsection of this vulnerability
section for more information about Internet Explorer Enhanced Security
Configuration.
Workarounds for FTP Server Response Parsing Memory Corruption
Vulnerability - CVE-2007-0217:
Microsoft has tested the following workarounds. Although these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.
* Read e-mail messages in plain text format if you are using Outlook 2002
or a later version, or Outlook Express 6 SP1 or a later version, to help
protect yourself from the HTML e-mail attack vector.
Microsoft Outlook 2002 users who have applied Office XP Service Pack 1 or
a later version and Microsoft Outlook Express 6 users who have applied
Internet Explorer 6 Service Pack 1 or a later version can enable this
setting and view e-mail messages that are not digitally signed or e-mail
messages that are not encrypted in plain text only.
Digitally signed e-mail messages or encrypted e-mail messages are not
affected by the setting and may be read in their original formats. For
more information about how to enable this setting in Outlook 2002, see
<http://support.microsoft.com/kb/307594> Microsoft Knowledge Base Article
307594.
For information about this setting in Outlook Express 6, see
<http://support.microsoft.com/kb/291387> Microsoft Knowledge Base Article
291387.
Impact of Workaround: E-mail messages that are viewed in plain text format
will not contain pictures, specialized fonts, animations, or other rich
content. Additionally:
* The changes are applied to the preview pane and to open messages.
* Pictures become attachments so that they are not lost.
* Because the message is still in Rich Text or HTML format in the store,
the object model (custom code solutions) may behave unexpectedly.
FAQ for FTP Server Response Parsing Memory Corruption Vulnerability -
CVE-2007-0217:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who
successfully exploited this vulnerability could remotely 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 handles specially crafted FTP server responses it
may corrupt system 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 these vulnerabilities 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?
In a Web-based attack scenario, an attacker would have to host an FTP
server that is used to attempt to exploit this vulnerability. An attacker
would have no way to force users to visit an FTP server. Instead, an
attacker would have to persuade them to visit the FTP server site,
typically by getting them to click a link on a Web page, in an e-mail
message, or in an Instant Messenger request that takes users to the
attacker's Web site.
What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user is logged on and visits an FTP
server using the FTP Client included in Internet Explorer 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 these vulnerabilities.
I am running Internet Explorer on Windows Server 2003. Does this mitigate
this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 runs in a
restricted mode that is known as
<http://msdn.microsoft.com/library/default.asp?url=/workshop/security/szone/overview/esc_changes.asp>
Enhanced Security Configuration. This mode sets the security level for the
Internet zone to High. This is a mitigating factor for Web sites that have not
been added to Internet Explorer Trusted sites zone. See the next FAQ in this
section for more information about Internet Explorer Enhanced Security
Configuration.
What is Internet Explorer Enhanced Security Configuration?
Internet Explorer Enhanced Security Configuration is a group of
preconfigured Internet Explorer settings that reduce the likelihood of a
user or administrator downloading and running malicious Web content on a
server. Internet Explorer Enhanced Security Configuration reduces this
threat by modifying numerous security-related settings, including Security
and Advanced tab settings in Internet Options. Some of the key
modifications include:
* Security level for the Internet zone is set to High. This setting
disables scripts, ActiveX components, Microsoft virtual machine (Microsoft
VM) HTML content, and file downloads.
* Automatic detection of intranet sites is disabled. This setting assigns
all intranet Web sites and all Universal Naming Convention (UNC) paths
that are not explicitly listed in the Local intranet zone to the Internet
zone.
* Install on Demand and non-Microsoft browser extensions are disabled.
This setting prevents Web pages from automatically installing components
and prevents non-Microsoft extensions from running.
* Multimedia content is disabled. This setting prevents music,
animations, and video clips from running.
For more information regarding Internet Explorer Enhanced Security
Configuration, please consult the Managing Internet Explorer Enhanced
Security Configuration guide, which can be found at the following
<http://www.microsoft.com/downloads/details.aspx?FamilyID=d41b036c-e2e1-4960-99bb-9757f7e9e31b&DisplayLang=en>
Web site.
What does the update do?
The update removes the vulnerability by modifying the way Internet
Explorer handles FTP server responses.
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.
ADDITIONAL INFORMATION
The information has been provided by Microsoft Security Bulletin MS07-016.
The original article can be found at:
<http://www.microsoft.com/technet/security/bulletin/ms07-016.mspx>
http://www.microsoft.com/technet/security/bulletin/ms07-016.mspx
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