Microsoft is working to strengthen Exchange Online phishing protection capabilities by adding support for External email tags to the cloud-based email service.
Once the feature is available, Exchange Online admins can increase protection against spam and phishing messages by automatically labeling all emails that come from external senders (outside the organization).
“This will be achieved by introducing a new tag in emails called 'External' in the message,” Microsoft explains.
“In some Outlook clients, a “mail tip” will be included at the top of the reading pane with the sender.”
The new External email tags will only appear in Outlook on the web, the new Outlook for Mac, and Outlook for mobile (iOS and Android).
How to enable external email markup
After it is rolled out to all Office 365 environments in standard multi-tenants worldwide later this month, the Exchange Online External tag feature will be disabled by default.
Administrators who want to enable it in their tenants should use the Get-ExternalInOutlook and Set-ExternalInOutlook PowerShell to view and modify external sender identification configuration in supported versions of Outlook.
“If you enable the cmdlet, within 24-48 hours, your users will start seeing a warning tag on emails received from external sources (outside your organization),” says Microsoft.
“In Outlook mobile, by clicking on the External tag at the top of the message, the user will see the sender's email.”
Microsoft is also working on adding SMTP MTA Strict Transport Security (MTA-STS) support to Exchange Online to prevent downgrade and man-in-the-middle (MITM).
Last year, Exchange Online added support for plus addressing (also known as secondary addressing or fine-grained addressing), allowing Office 365 customers to use unlimited disposable recipient email addresses to filter and identify email sources.
Information source: bleepingcomputer.com
