If your FreePBX is compromised by a hacker then take a look at this guide to get your FreePBX secured!
Learn how to add an IP phone to FreePBX! In this demo we used a Fanvil; but brands like SNOM, Yealink, Polycom, and Grandstream will be a similar process!
Change you FreePBX registration from registration to IP authentication.
How to set up your FreePBX with Voxtelesys and IP authentication.