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Credit:
The information has been provided by Microsoft Product Security.
The original article can be found at: http://www.microsoft.com/technet/security/Bulletin/MS06-044.mspx
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Affected Software:
Microsoft Windows 2000 Service Pack 4 - Download the update
Non-Affected Software:
* Microsoft Windows XP Service Pack 1 and 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
Mitigating Factors for MMC Redirect Cross-Site Scripting Vulnerability - CVE-2006-3643:
* Internet Explorer 6 Service Pack 1 on Windows 2000 Service Pack 4 will not open local files from the Internet Zone. Note that Explorer 6 Service Pack 1 will still open local files, and thus is vulnerable, from sites in the Local Intranet or Trusted Sites zones.
* An attacker would have to host a Web site that contains a Web page that is used 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 Web site. After they click the link, they would be prompted to perform several actions. An attack could only occur after they performed these actions.
* 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, Outlook Express 6, Outlook 2002, and Outlook 2003 open HTML e-mail messages in the Restricted sites zone. Additionally, Outlook 98 and Outlook 2000 open HTML e-mail messages in the Restricted sites zone if the Outlook E-mail Security Update has been installed. Outlook Express 5.5 Service Pack 2 opens HTML e-mail messages in the Restricted sites zone if Microsoft Security Bulletin MS04-018 has been installed. The Restricted sites zone helps reduce attacks that could try to exploit this vulnerability.
The risk of attack from the HTML e-mail vector can be significantly reduced if you meet all the following conditions:
* Apply the update that is included with Microsoft Security Bulletin MS03-040 or a later Cumulative Security Update for Internet Explorer.
* Use Internet Explorer 6 or a later version.
* Use the latest security update for Microsoft Outlook, use Microsoft Outlook Express 6 or a later version, or use Microsoft Outlook 2000 Service Pack 2 or a later version in its default configuration.
Workarounds for MMC Redirect Cross-Site Scripting Vulnerability - CVE-2006-3643:
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 active scripting in the My Computer zone
More information on the values being modified by this workaround can be found at the following Web site. There are two ways to deploy this workaround:
Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe.
Note We recommend backing up the registry before you edit
1. Click Start, click Run, type "regedit32 " (without the quotation marks), and then click OK.
2. In Registry Editor, locate the following registry key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\0
3. Double click the DWORD Value: 1400. Set the value to 3.
4. Close any instances of Internet Explorer. The change takes effect the next time Internet Explorer is started.
* 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 Microsoft Knowledge Base Article 307594.
For information about this setting in Outlook Express 6, see 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 MMC Redirect Cross-Site Scripting Vulnerability - CVE-2006-3643:
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. To attempt to exploit the vulnerability, an attacker must be able to log on locally to the system and run a program.
What causes the vulnerability?
HTML embedded resource files in the Microsoft Management Console library can be directly referenced from the Internet or Intranet zone via Internet Explorer, resulting in remote code execution.
Internet Explorer 5.01 users are vulnerable from any URLs in the Internet Zone.
Internet Explorer 6 Service Pack 1 users are vulnerable from any URLs in the Intranet Zone; by default Internet Explorer 6 Service Pack 1 blocks local file access from URLs in the Internet Zone.
What is Microsoft Management Console?
Microsoft Management console is an integrated administration user interface and administration model for Windows-based environments. See the Microsoft Management Console Web site.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take complete control of the affected system.
How could an attacker 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. 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?
Windows 2000 systems are primarily at risk from this vulnerability.
Could the vulnerability be exploited over the Internet?
Yes. An attacker could try to exploit this vulnerability over the Internet.
What does the update do?
The update removes the vulnerability by preventing specially crafted files and directories from invoking arbitrary code without specific user intervention.
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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