Usually coming from 100, 1000, or 10000 and then answering with silence on the other end. It turns out, these annoying calls are known as “phantom” calls or “ghost calls.”

This is a common problem with VoIP systems, and you are not alone in this frustration. These calls are an annoyance and can sometimes be a “canary in the coal mine” to indicate other problems with your voice provider or network security.

Why ghost calls happen?

These ghost calls are created from a number of auditing and hacking tools. These probes, often generated by a software package called SIP Vicious, scan phones on external IP addresses and look for responses. When they find your handset, they attempt to probe it to see if it will allow or accept unauthenticated traffic – a sure sign of a poorly secured network. If you are having these issues, we recommend you contact your network or voice administrator to see if there are security precautions that can be taken. Your VoIP provider also should be able to assist with some security recommendations to reduce your risk and the surface area of your phones’ exposure to this attack.

What is FluentStream doing about it?

On our own network at FluentStream, we have taken significant steps to configure our software to prevent these calls from happening. These include forcing our phones to only accept “known” server traffic, keeping up to date with our phone manufacturer’s software, and providing proactive monitoring of the health of our customer’s networks. Through this approach, we believe we can proactively stop many if not all of these attacks before they become more than an annoyance – or an actual security risk.

For a free – and no obligation – assessment of your network, please contact us

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