Who is Responsible for These Phantom Calls?

First of all, it should be pointed out that this is rarely due to your IP phone provider, though as we will find out, there are things we can do to block ghost calls.

Often these phantom phone calls are due to automated programs randomly scanning IP (Internet Protocol) ports, often referred to as port scans, to try and find susceptibilities in your phone system. They are doing this because if they find a way to break into your phone system, they can make calls on your dime. 
One common scanner that is used is known as SIPVicious. It is a free SIP (Session Initiation Protocol) test tool that is used by hackers to try and find open SIP ports to break into to try to retrieve the password for the extension. If SIPVicious is the culprit, the Caller ID of one of these ghost calls may show “SIPVicious”. If they are successful in brute forcing into a phone's extension, they can then clone the extension on their system and make calls that you will pay for.

However, these calls can also be due to neglected auto-dialers like the ones used by telemarketers. There are FCC (Federal Communications Commission) limits on how long they can tie up your phone line. If an auto-dialer is no longer actively managed but still making outbound calls, it could cause problems such as ghost calls. In other words, it calls your phone number without a telemarketer present to talk to you, resulting in the line being tied up and full of dead air until the FCC limit kicks in to terminate the call.

Stopping Ghost Calls

Regardless of who is responsible, ghost calls are annoying and can be dangerous if their goal is to attempt to brute force their way into your phone. However, there are various methods you can use to stop these rogue calls, some on the provider side and others on the end-user side.

Provider Side Fixes

• If you have our Mikrotik router installed, it will already be set up to prevent ghost calls caused by SIP scanners. If you have a Mikrotik and are still experiencing ghost calls, Primecall VoIP also has other security measures in place to ensure that no one can clone and use your extension to place calls on your dime. Ghost calls on our platform are nothing more than an annoyance. 
  • Please contact our technical support by calling 844.59PRIME (844.597-7463) or dialing HELP (4357) on a desk phone. We will make the necessary updates to your Mikrotik router to block the ghost calls.
     
• For the case of auto-dialer issues, they tend to have a real phone number in their incoming caller ID. To block all calls from that Caller ID, you can do this yourself from the secure portal. 
  • Just log in and block the associated rogue calls using this guide for the Primecall platform or this guide for the Enswitch platform.