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External email tagging coming to CU Boulder accounts

Submitted by stauffeg on

Starting March 26, external emails sent to CU Boulder students, faculty, staff and retirees will be tagged with a warning label: [External Email - Use caution]. Emails from approved sources like other CU campuses, the system office, and university-supported platforms, should not include the external tag.

Why we’re making this change

The external label serves as a reminder to be cautious about opening attachments or links from outside our organization in order to reduce the incidence of compromised accounts. Research has found that email warning banners and indicators change the behavior of 71 percent of participants and 84 percent said that they would influence the decision to act on an email.  

On average our campus is targeted by over 350 phishing attacks per day, and over the past six months, more than 1,000 CU Boulder accounts were reset due to compromise or suspected compromise. External email tagging is one more tool to help us fight back against this rising tide and does not affect the sending or receiving of emails. Labeling external emails is one of a variety of tools leveraged by our campus—along with email filters, domain protections that prevent spoofing, and advanced endpoint detection software—to help curtail the efficacy of phishing attacks.

Exceptions to tagging

External email tagging has been in use by the Office of Information Technology’s staff and CU’s Anschutz campus for some time now, and during this time, a list of third-party senders has been created to allow exceptions to tagging. Anyone who discovers senders that are incorrectly tagged as external can complete the External Email Tag Exception Request form or contact the IT Service Center and share why the sender should be added to the exception list.

Learn more

You can learn more about this upcoming change in OIT’s External Email Tagging FAQs where you will also find a link to the External Email Tag Exception Request form. If you have questions about this new feature or about CU Boulder email accounts in general, please contact the IT Service Center at or 303-735-4357.