Blocking Attachments with Outlook Web Access
Trend Micro’s “Q2 2005 Virus Roundup” report shows
that nearly all reported virus outbreaks began or are propagated through
email. Thankfully, Microsoft’s advances in the Outlook security tools
have greatly reduced/blocked unattended distribution of these damaging
programs. By blocking access to certain types of attachments (EXE, COM,
VBS for example) and by restricting programmatic access to the address
book and Outlook APS, it is much more difficult for an infected machine
to systematically send messages to everyone in the address book. In this
article, I will show you some tips and techniques for
attachment-handling for your OWA clients as well as some sneaky ways of
providing different access for different people.
In my humble opinion, the Outlook security
enhancements have tipped the scales back in our favor. Unfortunately,
these improvements do not necessarily apply to Outlook Web Access
clients. Yes, there are some tools you can use to modify attachment
handling in OWA, but you will find that they lack the granularity found
in the Outlook Security tools. For example, a desktop administrator can
build security setting templates in the public folder system to instruct
Outlook 2000 SR1 and newer clients how to handle attachments. You can
create a policy to block certain types of attachments for all users, and
then create an override group and template to allow access for others.
The same is true for those folks with PDAs who may
need some limited access to the Outlook object model from a
synchronization and replication tasks.
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