Test a Link / Decoding SafeLinks URLs

As part of Outlook and the Microsoft 365 suite’s Advance Threat Prevention, links in emails are checked by the SafeLinks service. When a user clicks on a link, it verifies that the link has neither been blocked by the University nor determined to be malicious. To perform this check, it rewrites the links into some form of https://nam10.safelinks.protection.outlook.com/?url=.…

This article covers how to reveal the original URL that was rewritten by the SafeLinks service.

Issue

The rewritten URL makes it difficult to uncover the destination of the original URL. It can also cause problems with copying and pasting links from emails into another document or web content.

Solution

Use a utility that decodes the URL, such as www.o365atp.com

  1. In the email message, right-click on the link and select Copy Hyperlink or Copy Link Address.

  2. Navigate to o365atp.com.

  3. Paste the link into the top box.

  4. The original URL will then be displayed in the Decoded URL box.

SafeLinks Decoder

Optional: Test the link in an isolated environment

You may visit https://www.browserling.com/ to use a virtual browser to visit a link in an environment that is isolated from your computer.

This service uses a virtual environment to visit web links and simply sends you the video feed; you can see what is happening without visiting the site yourself. Once you leave this environment, the environment deletes itself and then is recreated for the next user, isolating them from your visit.

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