[ISN] EEYE: Microsoft WordPerfect Document Converter Buffer Overflow

From: InfoSec News (isnat_private)
Date: Wed Sep 03 2003 - 22:34:37 PDT

  • Next message: InfoSec News: "[ISN] Twisters, hurricanes, floods (oh my)"

    Forwarded from: "Marc Maiffret" <marcat_private>
    Microsoft WordPerfect Document Converter Buffer Overflow
    Release Date:
    September 3, 2003
    Reported Date:
    May 6, 2003
    Medium (Code Execution with User Interaction)
    Systems Affected:
    Microsoft Office 97, 2000, XP
    Microsoft Word 98 (J)
    Microsoft FrontPage 2000, 2002
    Microsoft Publisher 2000, 2002
    Microsoft Works Suite 2001, 2002, 2003
    The Microsoft Word "WordPerfect" document converter included in Microsoft
    Word has a buffer overflow bug. If the WordPerfect document converter is
    installed (by default it is in Office 2000) and a malicious .doc file is
    opened, there exists the ability for an attacker to execute arbitrary code.
    This buffer overflow bug can also happen within Internet Explorer, because
    Microsoft Word is executed automatically as a helper-application when a .doc
    file is received.
    This buffer overflow overwrites the return address in the stack area. We
    confirmed that arbitrary code can be executed by using this buffer overflow
    Technical Description:
    While parsing a WordPerfect file, the WordPerfect converter copies data
    stored in the .doc file to a local buffer. If we modify some bytes of the
    .doc file, we can specify the data offset and data size. The WordPerfect
    converter doesn't properly check the size of the data contained in the .doc
    file, and tries to copy all of the data from the file to the local buffer
    allocated in the stack area. This results in a typical buffer overflow
    vulnerability in which we can set any value for EIP.
    The process for making the .doc file to confirm this buffer overflow is as
    [Technical data may wrap in eMail, please visit our website.]
    1. Open Word and save an empty document as wordPerfect 5.0 file.
    2. Open the .doc file in a binary editor. You'll be able to confirm the
    following dump image:
     ADDRESS   00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
     00000000  FF 57 50 43 6D 02 00 00 01 0A 00 00 00 00 00 00
     00000130  00 00 00 00 CD 01 00 00 08 00 02 00 00 00 CD 01
     000001C0  61 75 74 68 6F 72 00 65 45 79 65 00 00 00 00 FB
     000001D0  FF 05 00 32 00 00 00 00 00 01 01 6C 00 00 00 01
     000001E0  02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     000001F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    3. Modify 0x00 to 0x01 in offset 0x00000139.
    4. Modify 0x00 to the value more than 0x80 in offset 0x000001D8.
    5. Modify 0x00 to the value more than 0x01 in offset 0x000001E1 to
    6. Append garbage data (e.g., a long string of A's) onto the end of this
    Retina Network Security Scanner has been updated to identify this
    Vendor Status:
    Microsoft was notified on May 6, 2003, and has released a patch for this
    vulnerability. The patch is available at:
    Yuji "The Ninja" Ukai, eEye Digital Security
    Related Links:
    Retina Network Security Scanner - Free 15 Day Trial
    Shanti, Yukkie, TEX, Sakuranamiki people, AD200X people
    Copyright (c) 1998-2003 eEye Digital Security
    Permission is hereby granted for the redistribution of this alert
    electronically. It is not to be edited in any way without express consent of
    eEye. If you wish to reprint the whole or any part of this alert in any
    other medium excluding electronic medium, please e-mail alertat_private for
    The information within this paper may change without notice. Use of this
    information constitutes acceptance for use in an AS IS condition. There are
    NO warranties with regard to this information. In no event shall the author
    be liable for any damages whatsoever arising out of or in connection with
    the use or spread of this information. Any use of this information is at the
    user's own risk.
    Please send suggestions, updates, and comments to:
    eEye Digital Security
    ISN is currently hosted by Attrition.org
    To unsubscribe email majordomoat_private with 'unsubscribe isn'
    in the BODY of the mail.

    This archive was generated by hypermail 2b30 : Thu Sep 04 2003 - 01:16:29 PDT