[UNIX] Outlook Express Windows Address Book File Vulnerability (MS06-016)

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Outlook Express Windows Address Book File Vulnerability (MS06-016)
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SUMMARY

Microsoft Outlook Express is an e-mail and news client bundled with
certain versions of Microsoft Windows starting with Windows 95 OSR-2. It
is bundled with the Internet Explorer 4.0 web browser by Microsoft (also
bundled with some versions of Windows), and also available as a no-charge
download for the classic Apple Macintosh operating system (although not
for the newer Mac OS X, where it has been replaced by Microsoft Entourage,
which is sold as part of Microsoft Office for Macintosh). A remote code
execution vulnerability exists in Outlook Express when using a Windows
Address Book (.wab) file that could allow an attacker who successfully
exploited this vulnerability to take complete control of the affected
system.

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 affected than users who operate with administrative user rights.

DETAILS

Affected Software:
* Microsoft Windows 2000 Service Pack 4
* 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
* Microsoft Windows 98, Microsoft Windows 98 Second Edition (SE), and
Microsoft Windows Millennium Edition (Windows Me) Review the FAQ section
of this bulletin for details about these operating systems.

Affected Components:
* Outlook Express 6 on Microsoft Windows Server 2003 and Microsoft
Windows Server 2003 Service Pack 1 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=484DE679-5505-4196-BDD8-F7CF325AF0F5> Download the update
* Outlook Express 6 on Microsoft Windows Server 2003 x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=A7B10D8F-D9D7-4423-AA6D-C1C41D23794E> Download the update
* Outlook Express 6 Microsoft Windows Server 2003 on Itanium-based
Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based
Systems -
<http://www.microsoft.com/downloads/details.aspx?familyid=800BF687-BEE5-478F-A025-43CD16682F31> Download the update
* Outlook Express 6 on Microsoft Windows XP Service Pack 2 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=0DD827BC-6FA1-405A-933E-FB422A4E8096> Download the update
* Outlook Express 6 on Microsoft Windows XP Professional x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?familyid=FF772C0B-6F98-449D-B02E-C9C236068172> Download the update
* Outlook Express 6 Service Pack 1 on Microsoft Windows XP Service Pack 1
or when installed on Microsoft Windows 2000 Service Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=CDA93501-99CB-4F28-BB73-6438CAD081DB> Download the update
* Outlook Express 5.5 Service Pack 2 on Microsoft Windows 2000 Service
Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=E61A3D64-14FD-4976-BB03-C31CA6EE61E2> Download the Update

Note The security updates for Microsoft Windows Server 2003 and Microsoft
Windows Server 2003 Service Pack 1 also apply to Microsoft Windows Server
2003 R2.

Mitigating Factors for Microsoft Outlook Express when using a Windows
Address Book File Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0014>
CVE-2006-0014:
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.

In an e-mail attack scenario, an attacker could exploit the vulnerability
by sending a specially-crafted .wab file to the user and by persuading the
user to open the file.

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
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 site. In order for the exploit to take place, the
user would have to open the .wab file.

Workarounds for Microsoft Outlook Express when using a Windows Address
Book File Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0014>
CVE-2006-0014:
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.

* Back up and remove the .wab file association
Removing the WAB registry key helps protect the affected system from
attempts to exploit this vulnerability. To backup and remove the WAB
registry key, follow these steps:

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 it.

1. Click Start, click Run, type regedit" (without the quotation marks),
and then click OK.
2. Expand HKEY_CLASSES_ROOT, and then click .WAB.
3. Click File, and then click Export.
4. In the Export Registry File dialog box, type a file name in the File
Name box, and then click Save.
5. Click Edit, and then click Delete to remove the registry key.
6. In the Confirm Key Delete dialog box, you receive an Are you sure you
want to delete this key and all of its subkeys message. Click Yes.

Impact of Workaround: Users will not be able to open address books by
double clicking them. They will have to manually start the Windows Address
Book application and pass the address book to be used as a command line
parameter or they can import the address book from the File menu. This
does not affect the use of address books in Outlook Express.

FAQ for Microsoft Outlook Express when using Windows Address Book File
Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0014>
CVE-2006-0014:
What is the scope of the vulnerability?
A remote code execution vulnerability exists in Outlook Express when using
a Windows Address Book (.wab) file that could allow an attacker who
successfully exploited this vulnerability to take complete control of the
affected system.

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 affected than users who operate with administrative user rights.

What causes the vulnerability?
An unchecked buffer in the Windows Address Book (WAB) functions within
Outlook Express.

What is a Windows Address Book?
Windows provides an address book for storing contact information. The WAB
is an application and service that enables users to keep track of people.
The WAB has a local database and user interface for finding and editing
information about people, and it can query network directory servers using
Lightweight Directory Access Protocol (LDAP).

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 an e-mail attack scenario, an attacker could exploit the vulnerability
by sending a specially-crafted .wab file to the user and by persuading the
user to open the file. In order for the exploit to take place, the user
would have to save the .wab file to the desktop and open it using Outlook
Express.

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
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 site. In order for the exploit to take place, the
user would have to save the .wab file to the desktop and open it using
Outlook Express.

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?
No. Although Windows 98, Windows 98 Second Edition or Windows Millennium
Edition does contain the affected component, the vulnerability is not
critical. For more information about severity ratings, visit the following
Web site.

What does the update do?
The update removes the vulnerability by modifying the way that Outlook
Express, when using a .wab file, validates the length of a field before it
passes it to the allocated buffer.

When this security bulletin was issued, had this vulnerability been
publicly disclosed?
No. Microsoft received information about this vulnerability through
responsible disclosure. Microsoft had not received any information to
indicate that this vulnerability had been publicly disclosed when this
security bulletin was originally issued.

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 original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS06-016.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS06-016.mspx



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