[NT] Vulnerability in Visual Studio 2005 Could Allow Remote Code Execution (MS06-073)

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Vulnerability in Visual Studio 2005 Could Allow Remote Code Execution
(MS06-073)
------------------------------------------------------------------------


SUMMARY

This update resolves a public vulnerability in Microsoft Visual Studio
2005. 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.
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.

DETAILS

Affected Software:
* Microsoft Visual Studio 2005
<http://www.microsoft.com/downloads/details.aspx?FamilyId=C2682C53-8E9A-4C7D-B782-BE78512DCBFA> Download the update
* Visual Studio 2005 Standard Edition
* Visual Studio 2005 Professional Edition
* Visual Studio 2005 Team Suite
* Visual Studio 2005 Team Edition for Developers
* Visual Studio 2005 Team Edition for Architects
* Visual Studio 2005 Team Edition for Testers

Non-Affected Software:
* Microsoft Visual Studio 2005
* Visual Basic 2005 Express Edition
* Visual C++ 2005 Express Edition
* Visual C# Express Edition
* Visual J# Express Edition
* Visual Web Developer Express Edition
* Visual Studio 2005 Tools For Office
* Visual Studio 2005 Team Explorer
* Visual Studio 2005 Team Foundation Dual-Server
* Visual Studio 2005 Team Foundation Single Server
* Visual Studio 2005 Team Foundation Proxy
* Visual Studio 2005 Team Foundation Build
* Visual Studio 2005 Premier Partner Edition
* Microsoft Visual Studio 6.0 Service Pack 6
* Microsoft Visual Studio .NET 2002 Service Pack 1
* Microsoft Visual Studio .NET 2003 Service Pack 1

CVE Information:
WMI Object Broker Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4704>
CVE-2006-4704

WMI Object Broker Vulnerability - CVE-2006-4704:

A remote code execution vulnerability exists in the WMI Object Broker
control that the WMI Wizard uses in Visual Studio 2005.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 WMI Object Broker Vulnerability - CVE-2006-4704:
* 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 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.

* By default, this ActiveX control is not included in the default
allow-list for ActiveX controls in Internet Explorer 7. Only customers who
have explicitly approved this control by using the
<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ietechcol/cols/dnexpie/activex_security.asp> ActiveX opt-in feature are at risk to attempts to exploit this vulnerability. However, if a customer has used this ActiveX control in a previous version of Internet Explorer, then this ActiveX control is enabled to work in Internet Explorer 7, even if the customer has not explicitly approved it using the ActiveX opt-in Feature.

* 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.

* 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.

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.

* 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 section of this security update for more information about Internet Explorer Enhanced Security Configuration.

* Workarounds for WMI Object Broker Vulnerability - CVE-2006-4704:

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.

* Disable attempts to instantiate the WMI Object Broker control

You can disable attempts to instantiate this ActiveX control 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
{7F5B7F63-F06F-4331-8A26-339E03C0AE3D} 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\{7F5B7F63-F06F-4331-8A26-339E03C0AE3D}]
"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: The WMI Wizard in Visual Studio 2005 may no longer
display or function correctly.

* 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.

FAQ for WMI Object Broker Vulnerability - CVE-2006-4704:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
Improper validation of controls instantiated by WMI Object Broker causes
the vulnerability.

What is WMI Object Broker?
WMI Object Broker is an ActiveX control that the WMI Wizard uses in Visual
Studio 2005. When a user invokes the WMI Wizard feature of Visual Studio
2005, the wizard internally uses WMI Object Broker to instantiate other
controls.

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.

Who could exploit the vulnerability?
In a Web-based attack scenario, an attacker would have to host a Web site
that contains a Web page that is used to attempt to exploit this
vulnerability. An attacker would have no way to force users to visit a
specially crafted Web site. Instead, an attacker would have to persuade
them to visit the Web site, typically by getting them to click a link that
takes them to the attacker's site.

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 that have Visual
Studio 2005 installed where Internet Explorer is used frequently, such as
workstations or terminal servers, are at the most risk from this
vulnerability.

I am running Internet Explorer 7. Does this mitigate this vulnerability?
Yes. Customers who are running Internet Explorer 7 with default settings,
are not at risk until the WMI Object Broker control has been activated
through the ActiveX opt-in feature in the Internet Zone. However, if a
customer has used this ActiveX control in a previous version of Internet
Explorer, then this ActiveX control is enabled to work in Internet
Explorer 7, even if the customer has not explicitly approved it using the
ActiveX opt-in feature.

What is the ActiveX opt-in feature in Internet Explorer 7?
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 access 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. 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 section of this security update 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 that the WMI
Object Broker instantiates other controls.

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-2006-4704.

When this security bulletin was issued, had Microsoft received any reports
that this vulnerability was being exploited?
Yes. This security update addresses the vulnerability that is currently
being exploited. The vulnerability that has been addressed has been
assigned the Common Vulnerability and Exposure number CVE-2006-4704.


ADDITIONAL INFORMATION

The original article can be found at:
<http://www.microsoft.com/technet/security/bulletin/MS06-073.mspx>
http://www.microsoft.com/technet/security/bulletin/MS06-073.mspx



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