You can now self-report Spam via the Outlook application. On the top right of the toolbar, there is now a Report Message button (see the picture below). You can mark a message as Junk, Phishing or even Not Junk if something went to your Junk folder by accident. You no longer need to email the Division of IT with the message.
If you are using Outlook via the web, then use the Report dropdown at the top.
Note: Only report it if the email did NOT go to your Junk Mail folder.
For more information: http://help.mail.colostate.edu/tt_O365_junk_email_settings.aspx (Note: they have not updated this page with the new method yet)