Vulnerability Note VU#936529

Microsoft Jet Engine stack buffer overflow

Original Release date: 22 Mar 2008 | Last revised: 13 May 2008

Overview

The Microsoft Jet Engine contains a stack buffer overflow, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

Description

Microsoft Jet, or Joint Engine Technology, is a database engine that is used by several Microsoft products, including Access and Visual Basic. A Microsoft Access database uses the .MDB file extension by default. The Microsoft Jet Engine contains a stack buffer overflow in the handling of specially crafted database files.

Microsoft Word can link to Jet databases. In some cases, the database can be opened without prompting the user. This can allow Microsoft Word documents to be used as an attack vector for this vulnerability. Microsoft Outlook can also be used as an attack vector by either opening a specially crafted email message or by viewing such a message in the preview pane.

Impact

By convincing a user to open a specially crafted Word document or Jet database, such as a Microsoft Access .MDB file, a remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system.

Solution

Apply an update
This issue is addressed in Microsoft Security Bulletin MS08-028.

Block MDB files from being processed through your mail infrastructure


To detect Jet files that have possibly been renamed to another file type, search for files with any of the following 15-byte signatures at location 0x4 (no quotes):

    "Jet System DB  "
    "Standard Jet DB"
    "Temp Jet DB    "
    "MSISAM Database"
Configure Microsoft Outlook to view and edit email messages in plain text

According to Microsoft, this can be accomplished in the following ways:

Manual (User Interaction)
    Enterprise Users follow these steps to disable the Outlook feature to use Word as mail editor:

    1. Restart the machine.
    2. Open Outlook
    3. Click Tools, click Options, and then click the Mail Format tab.
    4. Clear the Use Microsoft Word to edit e-mail messages check box.
    5. Clear the Use Microsoft Word to read Rich Text e-mail messages box.
    6. Exit Outlook.
    7. Restart the machine.

    Impact of Workaround: Users will not be able to use Word as their e-mail editor or use Rich Text to read their e-mail
Using Group Policy
    Domain administrators can use Group Policy to disable Word as the users e-mail editor. You do not have to restart the computer to implement this mitigation.
    For information on using registry keys with a Group Policy see Using Administrative Template Files with Registry-Based Group Policy and Distributing Registry Changes.

    Disable WordMail in Word 2003

    Windows Registry Editor Version 5.00

    [HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Options\Mail]
    "EditorPreference"=dword:00020000
    "UseWordMail"=dword:00000000

    Disable WordMail in Word 2002

    Windows Registry Editor Version 5.00

    [HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Options\Mail]
    "EditorPreference"=dword:00020000
    "UseWordMail"=dword:00000000

    Impact of Workaround: Users will not be able to use Word as their e-mail editor or use Rich Text by default to read their e-mail.
Restrict the Microsoft Jet Database Engine from running

To implement the workaround, enter the following command at a command prompt:

echo y| cacls "%SystemRoot%\system32\msjet40.dll" /E /P everyone:N

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected16 Nov 200713 May 2008
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

This vulnerability was publicly reported by cocoruder.

This document was written by Will Dormann.

Other Information

  • CVE IDs: CVE-2007-6026 CVE-2008-1092
  • Date Public: 16 Nov 2007
  • Date First Published: 22 Mar 2008
  • Date Last Updated: 13 May 2008
  • Severity Metric: 58.22
  • Document Revision: 36

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