Why did the IU Mail Delivery System modify an email message I received?

To protect computers and data on the Indiana University network, UITS scans all inbound messages for viruses and other malware, and discards messages containing suspect content. However, not all messages can be scanned. Attachments that have been encrypted or password-protected cannot be scanned; similarly, other messages might be unscannable because they have been corrupted, or have attachments that use multiple levels of compression or archiving.

UITS does not discard these messages. Instead, the IU Mail Delivery System intercepts the message, adds warning text, and then sends it to the recipient:

  • Encrypted attachments: Many legitimate university and commercial senders use encrypted attachments, such as password-protected PDFs, ZIP files, or Microsoft Word or Excel documents. In these cases, the Mail Delivery System adds the following warning:

    This message contains encrypted material, and could not be scanned for viruses by the IU Mail Delivery System. If you do not trust the sender, treat the message with caution.

  • Other unscannable messages: Other messages are considered unscannable if the antivirus engine times out before the message is fully scanned, or if archive attachments are nested so deeply that they exceed the maximum scanning depth. In these cases, the Mail Delivery System adds the following warning:

    This message could not be scanned for viruses by the IU Mail Delivery System. It might have been corrupted, or might contain insecure content. If you do not trust the sender, treat the message with caution.

This is document bdap in the Knowledge Base.
Last modified on 2016-01-28 00:00:00.

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