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Security Update of ActiveX Kill Bits (MS08-023)
------------------------------------------------------------------------
SUMMARY
This security update resolves one privately reported vulnerability for a
Microsoft product. This update also includes a kill bit for the Yahoo!
Music Jukebox product. The vulnerability could allow remote code execution
if a user viewed 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.
The security update is rated Critical for Internet Explorer 5.01 Service
Pack 4 on Microsoft Windows 2000 Service Pack 4; Internet Explorer 6
Service Pack 1 when installed on Microsoft Windows 2000 Service Pack 4;
Windows XP Service Pack 2; and Windows XP Professional x64 Edition and
Windows XP Professional x64 Edition Service Pack 2.
The security update is rated Important for Windows Vista and Windows Vista
Service Pack 1; and Windows Vista x64 Edition and Windows Vista x64
Edition Service Pack 1.
The security update is rated Moderate for all supported editions of
Windows Server 2003.
For all other supported versions of Windows, this security update is rated
Low. For more information, see the subsection, Affected and Non-Affected
Software, in this section.
DETAILS
Affected Software:
Operating System - Component - Maximum Security Impact - Aggregated
Severity Rating - Bulletins Replaced by This Update
* Microsoft Windows 2000 Service Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=0395451F-B719-4F71-A7B4-403D0C7E8FCC>
Microsoft Internet Explorer 5.01 Service Pack 4 - Remote Code Execution -
Critical - None
* Microsoft Windows 2000 Service Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=BA6D3AEB-E35A-47CC-BACE-7BD9D58A9D3F>
Microsoft Internet Explorer 6 Service Pack 1 - Remote Code Execution -
Critical - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=9DBF002F-FE53-4CC7-A430-35F45C520D10>
Windows XP Service Pack 2 - - Remote Code Execution - Critical - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=01400970-DF68-4DAF-AA39-2FC4F969974C>
Windows XP Professional x64 Edition and Windows XP Professional x64 Edition
Service Pack 2 - - Remote Code Execution - Critical - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=AD384FEA-53BE-4BE3-8ACB-1CD23A7F5405>
Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 - -
Remote Code Execution - Moderate - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=FFC5C893-CB24-4875-B0A7-6D5C7AA4D642>
Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service
Pack 2 - - Remote Code Execution - Moderate - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=94CF78D3-B6C3-41BC-993E-3AF3BE0D70F1>
Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003
with SP2 for Itanium-based Systems - - Remote Code Execution - Moderate - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=D7F14001-7F42-4CA0-9193-CDF061179B59>
Windows Vista and Windows Vista Service Pack 1 - - Remote Code Execution -
Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=D33462B6-7391-482D-BABE-FB4CD0BEAA21>
Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1 - -
Remote Code Execution - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=95691924-2813-4A86-9E11-99D853F8E606>
Windows Server 2008 for 32-bit Systems - - Remote Code Execution - Low - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=920AE29B-19D0-4089-AC79-F2DA824A2256>
Windows Server 2008 for x64-based Systems - - Remote Code Execution - Low -
None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=66DF79AC-8364-4922-9688-EBC7EC76D89F>
Windows Server 2008 for Itanium-based Systems - - Remote Code Execution - Low
- None
ActiveX Object Memory Corruption Vulnerability - CVE-2008-1086
A remote code execution vulnerability exists in the ActiveX control
hxvz.dll. 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
CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1086>
CVE-2008-1086
Mitigating Factors for ActiveX Object Memory Corruption Vulnerability -
CVE-2008-1086
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 could contain specially crafted content that could
exploit this vulnerability. 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 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.
* 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 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.
Workarounds for ActiveX Object Memory Corruption Vulnerability -
CVE-2008-1086
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
<http://support.microsoft.com/kb/240797> 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.
Note The Class Identifiers and corresponding files where the ActiveX
objects are contained are documented under What does the update do? in
the FAQ for ActiveX Object Memory Corruption Vulnerability -
CVE-2008-1086 section. Replace {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}
below with the Class Identifiers found in this section.
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://technet2.microsoft.com/WindowsServer/en/library/6d7cb788-b31d-4d17-9f1e-b5ddaa6deecd1033.mspx?mfr=true>
Group Policy collection
*
<http://technet2.microsoft.com/windowsserver/en/library/47ba1311-6cca-414f-98c9-2d7f99fca8a31033.mspx?mfr=true>
What is Group Policy Object Editor?
*
<http://technet2.microsoft.com/windowsserver/en/library/e926577a-5619-4912-b5d9-e73d4bdc94911033.mspx?mfr=true>
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.
FAQ for ActiveX Object Memory Corruption Vulnerability - CVE-2008-1086
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 the ActiveX control is used in Internet Explorer, the control 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 convince a
user to view the Web site. This can 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 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.
I am running Internet Explorer for 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. 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 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?
This update sets the kill bit for a list of Class Identifiers (CLSIDs).
The Class Identifiers and corresponding files are as follows:
Class Identifier - File
{314111b8-a502-11d2-bbca-00c04f8ec294} - hxvz.dll
{314111c6-a502-11d2-bbca-00c04f8ec294} - hxvz.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.
ADDITIONAL INFORMATION
The information has been provided by Microsoft Product Security.
The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS08-023.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS08-023.mspx
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