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HistoryNov 21, 2002 - 12:00 a.m.

Microsoft Security Bulletin MS02-066: Cumulative Patch for Internet Explorer (Q328970)

2002-11-2100:00:00
vulners.com
17

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Title: Cumulative Patch for Internet Explorer (Q328970)
Date: 20 November 2002
Software: Internet Explorer
Impact: Execute commands on a user's system
Max Risk: Important
Bulletin: MS02-066

Microsoft encourages customers to review the Security Bulletins at:

http://www.microsoft.com/security/security_bulletins/ms02-066.asp
http://www.microsoft.com/technet/security/bulletin/MS02-066.asp.


Issue:

This is a cumulative patch that includes the functionality of all
previously released patches for IE 5.01, 5.5 and 6.0. In addition,
it eliminates the following six newly discovered vulnerabilities:

    • A buffer overrun vulnerability that occurs because Internet
      Explorer does not correctly check the parameters of a PNG graphics
      file when it is opened. To the best of Microsoft's knowledge, this
      vulnerability could only be used to cause Internet Explorer to
      fail. The effect of exploiting the vulnerability against Internet
      Explorer would be relatively minor - the user would only need to
      restart the browser to restore normal operation. However, a number
      of other Microsoft products - notably, most Microsoft Office
      products and Microsoft Index Server - rely on Internet Explorer to
      render PNG files, and exploiting the vulnerability against such an
      application would cause them to fail as well. Because of this,
      Microsoft recommends that customers install this patch regardless
      of whether they are using Internet Explorer as their primary web
      browser.
    • An information disclosure vulnerability related to the way that
      Internet Explorer handles encoded characters in a URL. This
      vulnerability could allow an attacker to craft a URL containing
      some encoded characters that would redirect a user to a second web
      site. If a user followed the URL, the attacker would be able to
      piggy-back the user's access to the second website. This could
      allow the attacker to access any information the user shared with
      the second web site.
    • A vulnerability that occurs because under certain circumstances
      Internet Explorer does not correctly check the component that the
      OBJECT tag calls. This could allow an attacker to obtain the name
      of the Temporary Internet Files folder on the user's local machine.
      The vulnerability would not allow an attacker to read or modify
      any files on the user's local system, since the Temporary Internet
      Files folder resides in the Internet security zone. Knowledge of
      the name of the Temporary Internet Files folder could allow an
      attacker to identify the username of the logged-on user and read
      other information in the Temporary Internet Files folder such as
      cookies.
    • Three vulnerabilities that although having differing root causes,
      have the same net effects. All three vulnerabilities result
      because of incomplete security checks being carried out when using
      particular programming techniques in web pages, and would have the
      effect of allowing one website to access information in another
      domain, including the user's local system. This could enable the
      web site operator to read, but not change, any file on the user's
      local computer that could be viewed in a browser window. In
      addition, this could also enable an attacker to invoke an
      executable that was already present on the local system.

In addition, the patch sets the Kill Bit on a legacy DirectX
ActiveX control which has been retired but which has a security
vulnerability. This has been done to ensure that the vulnerable
control cannot be reintroduced onto users' systems and ensures
that users who already have the control on their system are
protected. This is discussed further in Microsoft Knowledge Base
Article 810202.

The patch also makes a further refinement to cross domain
verification check that was first introduced in Internet Explorer
Service Pack 1.

Mitigating Factors:

With the exception of the Malformed PNG Image File Failure, there
are common mitigating factors across all of the vulnerabilities:

    • The attacker would have to host a web site that contained a web
      page used to exploit the particular vulnerability.
    • The attacker would have no way to force users to visit the site.
      Instead, the attacker would need to lure them there, typically by
      getting them to click on a link that would take them to the
      attacker's site.
    • By default, Outlook Express 6.0 and Outlook 2002 open HTML mails
      in the Restricted Sites Zone. In addition, Outlook 98 and 2000
      open HTML mails in the Restricted Sites Zone if the Outlook Email
      Security Update has been installed. Customers who use any of these
      products would be at no risk from an e-mail borne attack that
      attempted to exploit these vulnerabilities.

In addition to there are a number of individual mitigating factors:

Malformed PNG Image File Failure

    • Internet Explorer and other affected applications such as
      Microsoft Office and Microsoft Index Server could be successfully
      restarted after the failure.
    • Microsoft has not identified a method by which this buffer
      overrun can be used to execute code of the attacker's choice on
      the user's system.
    • This vulnerability is not present in Internet Explorer 6 Service
      Pack 1.

Encoded Characters Information Disclosure

    • The vulnerability would not enable an attacker to read, modify
      or execute any files on the local system.

Temporary Internet Files folder Name Reading

    • An attacker could not use this vulnerability to read, delete or
      modify any files on the user's local system other than information
      contained in the Temporary Internet Files folder.
    • An attacker could only exploit this vulnerability by having a
      user visit a malicious web site and then follow a malformed link
      on this malicious web site to a second web site that the user
      trusted.
    • This vulnerability is not present in Internet Explorer 6 Service
      Pack 1.

Frames Cross Site Scripting, Cross Domain Verification via Cached
Methods & Improper Cross Domain Security Validation with Frames

    • The vulnerabilities would only allow an attacker to read files
      on the user's local system that can be rendered in a browser
      window, such as image files, HTML files and text files.
    • The vulnerabilities would not provide any way for an attacker to
      put a program of their choice onto another user's system.
    • An attacker would need to know the name and location of any file
      on the system to successfully invoke it.
    • The vulnerabilities could only be used to view or invoke local
      executables. It could not be used to create, delete, or modify
      arbitrary or malicious files.

Risk Rating:

    • Important

Patch Availability:

Acknowledgment:

    • Microsoft thanks eEye Digital Security for reporting the
      malformed PNG issue to us and working with us to protect customers.

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE
FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN
IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE
EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR
INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

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