This blog post is going to demonstrate a proof of concept (PoC) of sending an e-mail to trigger the Mail app (mail.app) to create a reverse shell. The Mail app has built-in functionality that can trigger an Applescript to execute code when certain conditions (new e-mail in inbox from bob, deletion of e-mail, or an e-mail containing certain text) occur within the Mail app. This functionality provides a method to initiate a reverse shell without user interaction or placing a persistent mechanism in a well-known location. The method below will utilize this functionality to monitor e-mails from a particular user, upon receiving an e-mail from said user, a reverse shell will call back to our Powershell Empire server.
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