Type packetstorm
Reporter Georgi Guninski
Modified 2000-06-29T00:00:00


                                            `Georgi Guninski security advisory #13, 2000  
IE 5 and Excel 2000, PowerPoint 2000 vulnerability - executing programs  
Systems affected: IE 5.01, Excel 2000, PowerPoint 2000, Win98 - probably  
other versions, have not tested  
Risk: High  
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.  
Internet Explorer 5.01, Excel 2000 and PowerPoint under Windows 98  
(suppose other versions are also vulnerable, have not tested) allow  
executing programs when viewing a web page or HTML email message - in  
the latter case at least with IFRAME.  
This allows taking full control over user's computer.  
IE 5.01 allows getting dangereous ActiveX objects with the help of the  
<OBJECT> tag and Office 2000 applications.  
For example, the following code loads a .xla file:  
<object data="Book1.xla" id="sh1" width=0 height=0></object>  
where Book1.xla is just a .xls file renamed to .xla. The same result may  
be achieved with a .ppt or .xls file, probably other Office 2000 file  
The result is having an object in IE that has a method SaveAs().  
Suppose there are more dangerous methods, have little knowledge on  
Office 2000 objects.  
The SaveAs method may save the Excel Workbook (or Addin) or PowerPoint  
object in arbitrary location, including the Start Up folder.  
The content of the saved file is controllable and depends on the content  
of Book1.xla.  
If the saved file is for example a .hta file, it is possible to execute  
arbitrary programs on the user's computer.  
The code is:  
<object data="Book1.xla" id="sh1" width=0 height=0>  
function f()  
alert(fn+" sucessfully written");  
Demonstration is available at:  
Workaround: Disable Active Scripting or Disable Run ActiveX controls and  
Copyright 2000 Georgi Guninski  
Georgi Guninski