View attachment Step 4 – Adding the external email warning The list below is based on the Regex list from SwiftOnSecurity that you can find here on GitHub. Choose The recipient is … external/internal.In the new rule select the following options You can add as many rules as needed by using the + icon. We need to add extra conditions, to do this you will need to click on + Icon behind the rule. Choose The sender… is external/internal.And we also want to add a filter to match the subject or body against a list of words. We only want to apply the rule when the email comes from an external source. – Click on the plus and select Create a new Rule Step 2 – Give the rule a nameĮnter a name for the rule so you can easily recognize it later, for example, “external email warning” Step 3 – Configure Apply this rule if Step 1 – Create a new Mail Flow Rule in the Exchange Admin Center If you want to configure the external email warning for only a single-tenant, then it’s more convenient to use the Exchange Admin Center for this. Configure External Email Warning in Exchange Online At the end of the article, I also have a PowerShell script that you can use. We are first going to use the Office 365 Exchange Online Admin Center to configure the external email warning. Note I have also created a script that will show a warning then users receive an external email with the same display name as a user of your organization (Impersonation). You can use this method both in Exchange Online and Exchange On-Premise. To create the external email warning we are going to use Exchange Transport Rules. So we are not going to warn users for every single external email with this, only if the content or subject contains specific words or phrases. The custom warning allows us to warn users based on the content or subject of the email. It’s still a good idea to warn your users of malicious emails, even though we can now tag external emails in Exchange Online. Make sure that Targeted release for everyone is selected.Įxternal email warnings are custom messages that you can add to the top of the email.Click on Organization profile and select Release Preferences.You can verify the settings with the following cmdlet: Get-ExternalInOutlook The next step is to enable the external tagging in Exchange Online. Connect-ExchangeOnline -userPrincipalName Step 2 – Enable external tagging ![]() The first step is to connect to Exchange Online. ![]() Only new emails will get tagged after you enabled the feature, existing emails won’t. Note It can take up to 48 hours before the external tag will show up in Outlook. Make sure you have the Exchange Online module installed before you start. Outlook Mobile App – iOS and Android – version 4.2111.0 and higherĪt the moment we can only enable external email tagging through PowerShell.Outlook for Mac – Version 16.47 and higher.Outlook for Window – rollout started may 2021.The external tag is supported in the following versions of Outlook: Microsoft recently launched a new feature in Exchange Online to help increase the user’s awareness by automatically tagging external emails. Features like SPF, DKIM, and DMARC already do a great job in preventing most phishing emails, but we all know that it’s still not enough.Įspecially spoofed emails, which seem to have been sent from a trusted source in your organization, are a great security risk. Enable External Email TagĮxternal email tagging is an extra security layer to help protect you against phishing emails. In this article, I will explain how you can enable the Exchange Online External Tag and create custom external email warnings in Office 365 and Outlook. It allows us to show a warning for phrases like, “keep your password”, or “update your password” We can show the custom warning based on words in the subject or body, making it really versatile. The second option is to add a custom warning banner at the top of the email. This will enable a built-in warning between the subject and body of the email when the email is sent from outside your organization. The first one is enabling the external email tag in Exchange Online. There are basically two options, which you should both implement. We can prevent that by adding an external email warning or tag external emails. Typically users find them also hard to recognize and click too often on the links in the emails. The phishing emails are getting better every year making it hard to block them up front. ![]() Phishing emails are one the biggest security threads at the moment.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |