|
|
|
|
| |
Credit:
The information has been provided by Microsoft Secrity.
The original article can be found at: http://www.microsoft.com/technet/security/Bulletin/MS06-015.mspx
|
| |
Vulnerable Systems:
* Microsoft Windows 2000 Service Pack 4 Download the update
* Microsoft Windows XP Service Pack 1 and Microsoft Windows XP Service Pack 2 Download the update
* Microsoft Windows XP Professional x64 Edition Download the update
* Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1 Download the update
* Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based Systems Download the update
* Microsoft Windows Server 2003 x64 Edition Download the update
* Microsoft Windows 98, Microsoft Windows 98 Second Edition (SE), and Microsoft Windows Millennium Edition (ME) Review the FAQ section of this bulletin for details about these operating systems.
Windows Shell Vulnerability - CVE-2006-0012:
A remote code execution vulnerability exists in Windows Explorer because of the way that it handles COM objects. An attacker would need to convince a user to visit a Web site that could force a connection to a remote file server. This remote file server could then cause Windows Explorer to fail in a way that could allow code execution. An attacker who successfully exploited this vulnerability could take complete control of an affected system.
Mitigating Factors for Windows Shell Vulnerability - CVE-2006-0012:
* Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.
* In a Web-based attack scenario, 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 malicious 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.
* 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 described previously.
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 vulnerability could not be exploited automatically through e-mail. For an attack to be successful a user must open an attachment or click on a link that is sent in an e-mail message.
Workarounds for Windows Shell Vulnerability - CVE-2006-0012:
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.
Disable the Web Client service
Disabling the Web Client service will help protect the affected system from attempts to exploit this vulnerability. To disable the Web Client service, follow these steps:
1. Click Start, and then click Control Panel. Alternatively, point to Settings, and then click Control Panel.
2. Double-click Administrative Tools.
3. Double-click Services.
4. Double-click WebClient.
5. In the Startup type list, click Disabled.
6. Click Stop, and then click OK.
You can also stop and disable the Web Client service by using the following command at the command prompt:
sc stop WebClient & sc config WebClient start= disabled
Impact of Workaround: If the Web Client service is disabled, Web Distributed Authoring and Versioning (WebDAV) requests are not transmitted. If the Web Client service is disabled, any services that explicitly depend on the Web Client service will not start, and an error message will be logged in the System log. Windows Server 2003 users will not be able to use the "Open as Web Folder" functionality.
* Use the Group Policy settings to disable the WebClient service on all affected systems that do not require this feature.
Because the Web Client service is a possible attack vector, disable the service by using the Group Policy settings. You can disable the startup of this service at either the local, site, domain, or organizational-unit level by using Group Policy object functionality in Windows 2000 domain environments or in Windows Server 2003 domain environments.
Note You may also review the Windows Server 2003 Security Guide. This guide includes information about how to disable services.
For more information about Group Policy, visit the following Microsoft Web sites:
* Step-by-Step Guide to Understanding the Group Policy Feature Set
* Windows 2000 Group Policy
* Group Policy in Windows Server 2003
Impact of Workaround: If the Web Client service is disabled, Web Distributed Authoring and Versioning (WebDAV) requests are not transmitted. If the Web Client service is disabled, any services that explicitly depend on the Web Client service will not start, and an error message will be logged in the System log. Windows Server 2003 users will not be able to use the "Open as Web Folder" functionality.
Block TCP ports 139 and 445 at the firewall:
Although WebDAV uses TCP port 80 for outbound communication, TCP ports 139 and 445 can be used inbound to attempt to connect to this service and try to exploit this vulnerability. Blocking them at the firewall can help prevent systems that are behind that firewall from attempts to exploit this vulnerability. We recommend that you block all unsolicited inbound communication from the Internet to help prevent attacks that may use other ports. For more information about ports, visit the following Web site.
FAQ for Windows Shell Vulnerability - CVE-2006-0012:
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.
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?
Windows Explorer could allow COM objects to be used to execute arbitrary code.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take complete control of the affected system.
What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who do not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.
Are Windows 98, Windows 98 Second Edition or Windows Millennium Edition critically affected by this vulnerability?
Yes. Windows 98, Windows 98 Second Edition, and Windows Millennium Edition are critically affected by this vulnerability. Critical security updates for these platforms may not be available concurrently with the other security updates provided as part of this security bulletin. They will be made available as soon as possible following the release. When these security updates are available, you will be able to download them only from the Windows Update Web site. For more information about severity ratings, visit the following Web site.
What does the update do?
The update removes the vulnerability by preventing specially crafted files and directories from invoking arbitrary code without specific user interaction.
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.
Note The update for this vulnerability also addresses a publicly disclosed variation that has been assigned Common Vulnerability and Exposure number CVE-2004-2289.
|
|
|
|
|
