Blocked Email Attachments

Viruses often use email attachments to infect computers over the internet. People are particularly vulnerable to viruses spread by email attachments because the method of infection is so simple. Someone only needs to open an attachment to infect their computer.

UBC IT scans all email messages for viruses and phishing, stopping the majority of malicious messages. Because there is often a delay between the release of a new virus and the ability of anti-virus software to detect it, IT can also help prevent viruses from spreading by blocking some file types attached to email messages.

How Attachment Blocking Works

People who attempt to send an email message through Faculty and Staff email (FASmail) will receive a notification if their email meets the criteria below:

  • An infected message
  • A message identified as phishing
  • A message containing a blocked file-type (including those within unencrypted archive files)

The notification will explain to the UBC sender what has occurred, and how to send the attachment, if it is legitimate. A notification will not be sent to the external recipient.

For emails containing a blocked file type sent to a UBC recipient from outside of FASmail, a notification will be sent to the UBC recipient in addition to the external sender. Visit the Cybersecurity Confidential Communications website to view sample user notifications (CWL login/VPN connection required).

Attachments that are Currently Blocked

Blocking Viruses

Email passing through (including messages addressed to accounts at,,, and mail sent between FASmail accounts, is scanned for viruses. The mail relay servers reject email messages containing a virus, and an error is issued to the person who originally sent the message.

Blocking Phishing

The mail relay servers block messages identified as "phishing" whether or not they include an attachment. Like viruses, they generally aim to harm the recipient, and the same social engineering tricks are used to convince people to click on a URL designed to steal personal information.

Blocking by File Type

UBC IT currently blocks attachments with restriced extensions. Visit the UBC Cybersecurity Confidential Communications website to view a list of blocked file types (CWL login/VPN connection required).

If you need to send a legitimate attachment that is on the blocked list, refer to Sending Attachments on the Blocked List.