Note: This vulnerability as well as several more can be found at http://www.greyhats.cjb.net

Outlook Express Window Opener Script Execution Vulnerability 

[Tested]
Microsoft Outlook Express version 6.0.2800.1123.
Microsoft Windows XP sp2 

[Discussion]
Microsoft Outlook Express is prone to a vulnerability which will allow javascript to execute in the message window. Outlook Express uses a webbrowser control to view email messages, with all features except javascript, objects, and a couple more. Apparently, it only filters out stuff in the window.document object. If something were to access any other components of the window object, it would be given as much access as if the mail message had been an html document opened in internet explorer. 

The example presents the viewer with a link to a javascript page with the target set to "_blank" (opens the page in a new window). The javascript calls opener.execScript, displaying an alert with the message body's innerHTML. 

[Example]
http://freehost07.websamba.com/greyhats/msoeexecscript.htm