Microsoft Converter for WordPerfect Has Buffer Overflow That Lets Remote Users Execute Arbitrary Code
SecurityTracker Alert ID: 1007617|
SecurityTracker URL: http://securitytracker.com/id/1007617
(Links to External Site)
Updated: Sep 3 2003|
Original Entry Date: Sep 3 2003
Execution of arbitrary code via network, User access via network|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): Office/Word 97, 98 (J), 2000, XP|
A buffer overflow vulnerability was reported in Microsoft's WordPerfect converter, part of Microsoft Office, Word, PowerPoint, FrontPage, Publisher, and Works. A remote user can execute arbitrary code on a target user's computer when the target user opens a document.|
eEye Digital Security reported that the converter does not properly validate certain parameters when opening a Corel WordPerfect document. A remote user can create a malicious document that, when opened, will trigger a buffer overflow and execute arbitrary code. The code will run with the privileges of the target user.
The converter is installed by default in all of the vulnerable product versions, according to the vendor.
According to eEye, the converter does not properly validate the size of the data in a '.doc' file and attempts to copy all the data from the file to a buffer allocated in the stack area. As a result, the EIP register can be overwritten and arbitrary code can be executed.
Some technical details on the format required to trigger the overflow are provided in the Source Message.
A remote user can create a document that, when opened by the target user, will cause arbitrary code to be executed with the privileges of the target user.|
The vendor has issued the following fixes:|
For Office XP, FrontPage 2002, Publisher 2002, Works 2002, and Works 2003:
For Office 2000, FrontPage 2000, Publisher 2000, and Works 2001:
For Office 97 and Word 98(J), see:
Microsoft recommends that users visit Office Update at:
The Office XP patch can be installed on Office XP SP2, Microsoft Works 2002, and Microsoft Works 2003. The administrative update can also be installed on Office XP SP1, as well.
The Office 2000 patch can reportedly be installed on Office 2000 SP3 and Works 2001.
A reboot is not necessary after applying this patch.
Microsoft has issued the following Knowledge Base article regarding this flaw:
Vendor URL: www.microsoft.com/technet/security/bulletin/MS03-036.asp (Links to External Site)
|Underlying OS: Windows (Any)|
This archive entry has one or more follow-up message(s) listed below.|
Source Message Contents
Subject: EEYE: Microsoft WordPerfect Document Converter Buffer Overflow|
Microsoft WordPerfect Document Converter Buffer Overflow
September 3, 2003
May 6, 2003
Medium (Code Execution with User Interaction)
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
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
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
Retina Network Security Scanner - Free 15 Day Trial
Shanti, Yukkie, TEX, Sakuranamiki people, AD200X people
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