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Microsoft Security Advisory: Vulnerability in Internet Explorer could allow information disclosure

Microsoft is investigating public reports of a vulnerability in Internet Explorer 6, Internet Explorer 7, and Internet Explorer 8. Internet Explorer 9 and Internet Explorer 10 are not affected by the vulnerability. Microsoft is aware of targeted attacks that attempt to exploit this vulnerability through Internet Explorer 8. Applying the Microsoft Fix it solution, “MSHTML Shim Workaround,” prevents the exploitation of this issue. See the Suggested Actions section of this advisory for more information.

The vulnerability is a remote code execution vulnerability that exists in the way that Internet Explorer accesses an object in memory that has been deleted or has not been properly allocated. The vulnerability may corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user within Internet Explorer. An attacker could host a specially crafted website that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the website.

On completion of this investigation, Microsoft will take the appropriate action to protect our customers, which may include providing a solution through our monthly security update release process, or an out-of-cycle security update, depending on customer needs.

 

The Fix it solution that is described in this section is not intended to be a replacement for any security update. We recommend that you always install the latest security updates. However, we offer this Fix it solution as a workaround option for some scenarios.

For more information about this workaround, go to the following Microsoft Security Advisory webpage:

The advisory provides more information about the issue, including the following:

  • The scenarios in which you might apply or disable the workaround.
  • How to manually apply the workaround.

Specifically, to see this information, look for the General Information heading, expand the Suggested actions section, and then expand the Workaround section.

To enable or disable this Fix it solution, click the Fix it button or link under the Enable heading or under the Disable heading. Click Run in the File Download dialog box, and then follow the steps in the Fix it wizard.

Enable MSHTML shim workaround

Microsoft Fix-It Icon

Disable MSHTML shim workaround

Microsoft Fix-It Icon

Fix this problem
Microsoft Fix it 50971
Fix this problem
Microsoft Fix it 50972

Notes

  • These wizards may be in English only. However, the automatic fixes also work for other language versions of Windows.
  • If you are not on the computer that has the problem, you can save the automatic fix to a flash drive or to a CD, and then you can run it on the computer that has the problem.
  • If you want to run a quiet installation of this Fix it solution, follow these steps:
    1. Open an elevated Command Prompt window with administrator credentials.
    2. Type the following command, and then press Enter:
      msiexec /i MicrosoftFixit50971.msi /quiet

Deploying an application compatibility database across multiple computers

To deploy an application compatibility database across multiple computers, you can use a system management solution, such as Microsoft System Center Configuration Manager 2007, and then use the SDBInst.exe command-line tool to install the database. For detailed information about how to use the SDBInst application, go to the following TechNet webpage:

To deploy Microsoft Fix it 50971 to multiple computers by using SDBInst, follow these steps:

Note For more information about command-line options for installing this fix, see the following MSDN webpage:

  1. Extract the CAB file from the Fix it package. To do this, type the following command at a command prompt:
    msidb.exe -x CabFile -d MicrosoftFixit50971.msi

    Note Msidb.exe is part of Windows Installer Development Tools. For more information, go to the following Microsoft webpage:

  2. Extract the SDB files from CabFile by using any CAB extraction utility:
    extract.exe /E CabFile
  3. Use SDBInst to apply the previously extracted .sdb files. To do this, type the following command at a command prompt:
    SDBInst -p Path_of_sdb_file\FileName.sdb

    File hash table

    The following table lists the thumbprints of the certificates that are used to sign the .sdb files. Verify the certificate thumbprint in this table against the certificate thumbprint that is indicated on the .sdb that you extracted.

    File Name Hash information
    mshtml_shim32.sdb (SHA1 695750970F6595D247FA30775579BD22E034252B)
    mshtml_shim64.sdb (SHA1 29444332522F8F06A88953071B3BA13C14FBD70A)

Technical Details:

Mitigating Factors:

  • By default, Internet Explorer on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 runs in a restricted mode that is known as Enhanced Security Configuration. This mode mitigates this vulnerability.
  • By default, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML email messages in the Restricted sites zone. The Restricted sites zone, which disables script and ActiveX controls, helps reduce the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an email message, the user could still be vulnerable to exploitation of this vulnerability through the web-based attack scenario.
  • An attacker who successfully exploited this vulnerability could gain the same user rights as the current 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.
  • In a web-based attack scenario, an attacker could host a website that contains a webpage that is used to exploit this vulnerability. In addition, compromised websites and websites 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 websites. Instead, an attacker would have to convince users to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes users to the attacker’s website.

Recommendation. Please see the Suggested Actions section of this advisory for more information.

Advisory Details

Issue References

For more information about this issue, see the following references:

References Identification
CVE Reference CVE-2012-4792
Microsoft Knowledge Base Article Microsoft Knowledge Base Article 2794220

Affected and Non-Affected Software

This advisory discusses the following software.

Affected Software

Operating System Component
Internet Explorer 6
Windows XP Service Pack 3 Internet Explorer 6
Windows XP Professional x64 Edition Service Pack 2 Internet Explorer 6
Windows Server 2003 Service Pack 2 Internet Explorer 6
Windows Server 2003 x64 Edition Service Pack 2 Internet Explorer 6
Windows Server 2003 with SP2 for Itanium-based Systems Internet Explorer 6
Internet Explorer 7
Windows XP Service Pack 3 Internet Explorer 7
Windows XP Professional x64 Edition Service Pack 2 Internet Explorer 7
Windows Server 2003 Service Pack 2 Internet Explorer 7
Windows Server 2003 x64 Edition Service Pack 2 Internet Explorer 7
Windows Server 2003 with SP2 for Itanium-based Systems Internet Explorer 7
Windows Vista Service Pack 2 Internet Explorer 7
Windows Vista x64 Edition Service Pack 2 Internet Explorer 7
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 7
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 7
Windows Server 2008 for Itanium-based Systems Service Pack 2 Internet Explorer 7
Internet Explorer 8
Windows XP Service Pack 3 Internet Explorer 8
Windows XP Professional x64 Edition Service Pack 2 Internet Explorer 8
Windows Server 2003 Service Pack 2 Internet Explorer 8
Windows Server 2003 x64 Edition Service Pack 2 Internet Explorer 8
Windows Vista Service Pack 2 Internet Explorer 8
Windows Vista x64 Edition Service Pack 2 Internet Explorer 8
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 8
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 8
Windows 7 for 32-bit Systems Internet Explorer 8
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 8
Windows 7 for x64-based Systems Internet Explorer 8
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 8
Windows Server 2008 R2 for x64-based Systems Internet Explorer 8
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 8
Windows Server 2008 R2 for Itanium-based Systems Internet Explorer 8
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 Internet Explorer 8

Non-Affected Software

Operating System Component
Internet Explorer 9
Windows Vista Service Pack 2 Internet Explorer 9
Windows Vista x64 Edition Service Pack 2 Internet Explorer 9
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 9
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 9
Windows 7 for 32-bit Systems Internet Explorer 9
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 9
Windows 7 for x64-based Systems Internet Explorer 9
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 9
Windows Server 2008 R2 for x64-based Systems Internet Explorer 9
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 9
Internet Explorer 10
Windows 8 for 32-bit Systems Internet Explorer 10
Windows 8 for 64-bit Systems Internet Explorer 10
Windows Server 2012 Internet Explorer 10
Windows RT Internet Explorer 10
Server Core installation
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) Not applicable
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) Not applicable
Windows Server 2008 R2 for x64-based Systems (Server Core installation) Not applicable
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) Not applicable
Windows Server 2012 (Server Core installation) Not applicable

Frequently Asked Questions

Suggested Actions

Apply Workarounds

Workarounds refer to a setting or configuration change that does not correct the underlying issue but would help block known attack vectors before a security update is available. See the next section, Workarounds, for more information.

Workarounds
Additional Suggested Actions
  • Keep Third-party Software UpdatedCurrent exploits of this type of vulnerability in Internet Explorer use third-party software, including Oracle’s Java, to help obtain reliable exploitation.

    For more information about keeping Java updated, see the following:

  • Protect your PCWe continue to encourage customers to follow our Protect Your Computer guidance of enabling a firewall, getting software updates and installing antivirus software. For more information, see Microsoft Safety & Security Center.
  • Keep Microsoft Software UpdatedUsers running Microsoft software should apply the latest Microsoft security updates to help make sure that their computers are as protected as possible. If you are not sure whether your software is up to date, visit Microsoft Update, scan your computer for available updates, and install any high-priority updates that are offered to you. If you have automatic updating enabled and configured to provide updates for Microsoft products, the updates are delivered to you when they are released, but you should verify that they are installed.

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