Append E-Mail banner for external mails in Exchange Online E-Mail Tagging

Lot’s of cyber attacks are based in malicious e-mails and use the good faith of users. That’s why you should train and sensitize your users. A simple and effective way is to visualize the danger with a small banner. In this article you get the information to create a rule with an “caution” banner.

In Exchange it’s quite easy to create this banner, it’s a simple exchange rule.

<table style="height: 10px; width: 100%; border-collapse: collapse; border-style: dotted;" border="1">
<tbody>
<tr style="height: 10px;">
<td style="width: 100%; height: 10px;">
<h4><strong><span style="background-color: #ffff00;"><span style="color: #ff0000;">WARNUNG</span>: diese Mail wurde von extern zugestellt. Bitte nicht auf Links klicken oder Anh&auml;nge &ouml;ffnen, wenn Sie den Absender nicht kennen!</span></strong></h4>
</td>
</tr>
</tbody>
</table>

This banner can be edited with HTML code generators found in the internet.

Another option is to add an prefix to the subject.

In this Case “EXTERN ||” is added to every external mail.

NOTE: signed e-mail can not be treated by this method, so they will be attached as file in the mail. This behavior may confuses your users, so there is a little workaround for this “problem”, see here.

Have fun with your new email banners. I’m looking forward for comments. If you like the article please click on “helpful”.