Better Handling of Blocked E-mail Attachments

Last Updated: 02/25/2014

To prevent potential viruses from infecting your computer, OIT's email security system blocks file types that are commonly used to package malicious content from arriving in your Inbox. Currently, this is accomplished by quietly denying delivery of the entire email message.

Beginning Thursday, February 13, OIT is improving the way our email security system handles incoming email messages containing potentially malicious file attachments. Instead of quietly denying delivery of the entire email message, the original message body will now be allowed through intact so that recipients are aware of the message. The attachment will be removed from this message and replaced with a simple text file indicating that the attachment was removed. In addition, the following notification will be placed at the top of the email message body:

This message originally contained an attachment that has been removed for your protection. The removed attachment had a file extension that is commonly used to package malicious content. If you were expecting the file, please contact the sender to arrange for an alternate delivery option. If you have questions about the attachment removal process, you are also welcome to contact the IT Service Center at help@colorado.edu or 303-735-4357 (5-HELP from a campus phone). To learn more about these malicious file types, please go to www.colorado.edu/oit/services/messaging-collaboration/e-mail-delivery-ma....

For your reference, the file extensions that will be automatically stripped from incoming emails are listed next. Please note that compressed .zip files will also be removed if those .zip files contain files with one of these extensions.

ade, adp, ani, bas, bat, chm, cmd, com, cpl, crt, dll, exe, hlp, hta, inf, ins, isp, js, jse, lnk, mdb, mde, msc, msi, msp, mst, pcd, pif, reg, scr, sct, shb, shs, vb, vbe, vbs, wri, wsc, wsf, wsh

If you have any questions or concerns regarding this new process, don't hesitate to contact the IT Service Center at help@colorado.edu or 303-735-4357 (5-HELP from a campus phone).