I've seen URLScan fail when a user who's last name was POL to allow this
user to open up his mailbox. POL is an extension that is normally blocked.
--------------------------
Martin Tuip
MVP Exchange
Exchange2000 List owner
www.exchange-mail.org
www.sharepointserver.com
[EMAIL PROTECTED]
--------------------------
----- Original Message -----
From: "Tom.Gray" <[EMAIL PROTECTED]>
To: "Exchange Discussions" <[EMAIL PROTECTED]>
Sent: Tuesday, October 01, 2002 5:39 PM
Subject: Another reason to be careful with OWA and URLSCAN
URLSCAN is a great tool. It helps secure your web server. If you use the
Outlook Web Access template when installing URLSCAN you should be "good to
go", right?
WRONG! URLSCAN wreaks havoc with OWA.
First, remember that with OWA the SUBJECT line of a mail message is the FILE
NAME. So if you are logged into OWA and want to read a message with
subject:
I want to hold your hand
Your browser sends a URL like the following
htps:/servername/username/inbox/i%20want%20to%20hold%your%20hand.eml
URLSCAN examines that URL to make sure it isn't evil. Looks good so far.
If the subject is:
I want to hold your hand.
The url would be
htps:/servername/username/inbox/i%20want%20to%20hold%your%20hand..eml
Since there are two dots (..) URLSCAN Rejects it.
And if the subject is:
I want to hold your hand & foot
The URL would be
htps:/servername/username/inbox/i%20want%20to%20hold%your%20hand%20%26%20foo
t.eml
Since there is an "&" (or hex 26) URLSCAN Rejects it.
Now how common is a period at the end of a subject in email? How common is
the perfectly RFC822 legal "&" in the subject of a message?
There are truly good reasons to reject those chars/patterns as URL's, but
they are allowed as file names. So do you a) lower the security of your
webserver by disabling those features of URLSCAN?
b) convince everyone to not end their subjects with a period or use the &
symbol?
hmmmmm, what were the OWA guys thinking (or smoking?) when they set up the
URL's to be based on subject lines???????
Tom Gray, Network Engineer
All Kinds of Minds & The Center for Development and Learning
University of North Carolina at Chapel Hill
Internet: [EMAIL PROTECTED]
AT&T Net: (919)960-8888
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