word-access.txt

`Georgi Guninski security advisory #17, 2000  
  
MS Word and MS Access vulnerability - executing arbitrary programs, may  
be exploited by IE/Outlook  
  
Systems affected: MS Word and MS Access 2000 (with or without Service  
Release 1a)  
IE and Outlook may be also used, but are not needed / Windows 98 -  
almost sure other versions, have not tested  
Risk: HIGH  
Date: 7 August 2000  
  
Disclaimer:  
The opinions expressed in this advisory and program are my own and not  
of any company.  
The usual standard disclaimer applies, especially the fact that Georgi  
Guninski  
is not liable for any damages caused by direct or indirect use of the  
information or functionality provided by this program.  
Georgi Guninski, bears NO responsibility for content or misuse of this  
program or any derivatives thereof.  
  
Legal Notice:  
This Advisory is Copyright (c) 2000 Georgi Guninski. You may distribute  
it unmodified. You may not modify it and distribute it or distribute  
parts of it without the author's written permission.  
  
Description:  
MS Word and MS Access 2000 (with or without Service Release 1a) allow  
executing arbitrary programs if a Word document is opened.  
This may be exploited also by visiting a web page with IE or  
opening/previewing HTML email message with Outlook.  
In order this to work, the user must be able to access a mdb file, which  
resides either on an UNC share or a local drive.  
This allows taking full control over user's computer.  
  
Details:  
  
The problem is MS Word accepts an Access database as a data source in  
Mail Merge.  
Worse, Word opens the database and executes VBA in forms that are opened  
at database startup.  
VBA allows executing arbitrary programs.  
  
How to reproduce:  
  
1) Create a db4.mdb file which opens a form at database startup and  
executes VBA code in the form.  
2) Place a copy of db4.mdb in C:\ (for example), you may place it on a  
UNC share.  
3) Open a Word document.  
4) Select Tools->Mail Merge->Create->Mailing Labels->New Main Document  
5) Select GetData->Open Data Source  
6) Choose C:\db4.mdb  
7) The rest of the wizard is trivial, you must save the new document.  
  
Sample files are available:  
http://www.nat.bg/~joro/wordaccess.doc  
http://www.nat.bg/~joro/db4.mdb  
  
Note: This is completely different issue from "Georgi Guninski security  
advisory #14, 2000"  
"IE 5 and Access 2000 vulnerability - executing programs", which needs  
IE and ActiveX, while the current bug is in Word/Access.  
  
  
-----------in Form1 of db4.mdb---------------------  
Private Sub Form_Load()  
On Error GoTo Err_Command0_Click  
Dim stAppName As String  
stAppName = "C:\Program Files\Accessories\wordpad.exe"  
MsgBox ("Trying to start: " & stAppName)  
Call Shell(stAppName, 1)  
  
Exit_Command0_Click:  
Exit Sub  
  
Err_Command0_Click:  
MsgBox Err.Description  
Resume Exit_Command0_Click  
End Sub  
---------------------------------------------------  
Form1 is automatically opened at database startup.  
You must have a table in the database.  
  
  
Regards,  
Georgi Guninski  
http://www.nat.bg/~joro  
  
`