US Defence Department against Microsoft Outlook
The Defense Department has banned the use of Outlook Web Access email and is blocking all HTML email, as it raises network security conditions from the normal Information Condition (Infocon) 5 to Infocon 4, indicating heightened vigilance in preparation for operations or exercises or increased monitoring of networks due to increased risk of attack, Federal Computer Week reports.
It is largely known that HTML-files can be infected by spyware allowing malicious persons access the computer and the computer network. Hackers also have the possibility of cracking the mailbox password once it is accessed by Microsoft Outlook Web Access and then freely read Pentagon workers' confidential letters.
We'd like to mention that The Bat! uses its own module for viewing letters in HTML format. The module is not connected to Microsoft Outlook or Internet Explorer. That's why the abovementioned threats can not damage The Bat! users.
http://www.malwarehelp.org/news/article-5637.html
http://government.zdnet.com/index.php?p=2796