When your phone rings, you answer it, and there’s nothing but silence on the other end, that’s a ghost call.

Ghost calls, also called phantom calls, are a real problem for individuals and businesses. Apart from being purely annoying, they can also turn into some very expensive headaches if you don’t take steps to prevent them.

Fortunately, there’s a lot you can do to rid yourself of ghost calls—and it doesn’t take much to get started.

Where Do Ghost Calls (Really) Come From?

Despite the name, ghost calls don’t come from the great beyond. Instead, they usually come from scammers trying to exploit vulnerabilities in your phone system. This is why most ghost calls are initiated by autodialers or come as a result of something called port scanning.

In the case of autodialers, you might get ghost calls from unethical call centers or telemarketers using them ineffectively. Since the Federal Communications Commission (FCC) has put limits on how long an auto-dialer can ring, its software will automatically hang up the call once that time is reached. If you answer the call around the time it disconnects, all you’ll hear is silence.

In the case of port scanning, the software looks for SIP ports, which are the gateways that connect things like a VoIP phone to the internet or two computers on the same network to each other—like in a call center with centralized communications.

Once the program finds a SIP port, scammers may then try to hack it to clone your phone system, find out passwords, and perhaps even access other devices on your network. If they gain access to your phone system, they’ll be able to make calls from your numbers, racking up charges that you have to pay while also undermining people’s trust in your business.

Keep in mind that there’s a difference between a ghost call and a pair of other common scams––the “one ring” scam, and a neighbor spoofing scam.

  • With a one ring scam, someone will dial and deliberately hang up after the first ring, hoping that you’ll be curious enough to call the missed number back. If you do, they’ll then try to sell you something. In other cases, they’ll have the number connected to an international toll number, which will cause you to have a charge on your phone bill. They may also be in cahoots with a service provider to get a percentage of that call cost, leaving you with a surprise bill.
  • In the neighbor spoofing scam, someone will make a call using software to make it look like they’re calling from a local number. This preys on the notion that people are much more likely to answer calls they believe to be local. Once you answer, you’re usually routed to a call center, where someone tries to sell you something.

Finally, be aware that it’s possible to create a ghost call yourself––by pocket dialing accidentally. While most pocket dials aren’t malicious, they can still be inconvenient.

How to Identify Ghost Calls

Ghost calls aren’t always easy to spot before answering, so it can be tempting to ignore them or get tricked into thinking they’re something else. One of the easiest ways to spot them is if you get a call that looks like it’s from a weird number, especially one that doesn’t have all 10 numbers, or starts with a 100, 1000, or 1001.

If your caller ID says something like “Call from Unknown” or “Unknown Host,” that’s your first sign that it might be a scammer. Similarly, if you see any incoming calls or calls in your log that say anything like “SIPVicious,” that’s almost certainly a ghost call. (SIPVicious is a free SIP troubleshooting program that’s been co-opted by scammers to scan for SIP ports.)

You may also want to look for patterns in calls you receive. For instance, if you get a lot of calls at night or if you find that your phone rings and hangs up over and over again, those are most likely ghost calls. Similarly, if you call one of these numbers back and get a message like, “This number is no longer in service,” that’s probably a ghost call.

Finally, if you receive a lot of calls that don’t show up in your Call Detail Records (CDRs), those are usually ghost calls as well. Your CDR should show you all the details about your phone system’s activity (including yours and that of anyone else on your system), so if you’re getting calls that don’t make it onto that list, you’re dealing with a ghost caller.

What to Do if You Use a Cloud or VoIP System

What Your Provider Can Do

More VoIP providers provide built-in security measures to help prevent ghost calls, so talk with your provider about the platform’s security and work with the support team to make sure your software remains up to date. You may want to ask if it’s possible to disable international calling––assuming you don’t need it––and report any ghost calls you get so the provider can update its blocking logs and make complaints about repeat offenders.

What You Can Do

The quickest and easiest thing you can do to protect yourself from ghost calls is to change your SIP port from the default 5060 port and disable direct IP calls. Since most SIP scanners only look for the most common port numbers before dialing via IP calling, this will drastically reduce your vulnerability.

You should also make sure that you’re using a firewall and require anyone else who uses your system (such as remote employees) to use a firewall on their devices as well.

Finally, keep your hardware and software up to date and use common sense security measures like strong passwords on your system. Train any employees to recognize ghost calls and require them to use strong passwords as well. You may also want to consider using a Virtual Private Network (VPN) for your calls and those of your staff.

How to Handle Ghost Calls if You Have a Landline

What Your Provider Can Do

Like VoIP providers, landline phone providers maintain lists of numbers and organizations that are known to do shady things with their calls and automatically block them from going through to your number. However, these lists can’t block everything, so it’s important to report any suspected ghost calls to your provider so they can be added to those lists.

What You Can Do

The best way to block ghost calls with a traditional phone is to buy a phone that has call blocking built in. This way, whenever someone calls, they have to say their name before the phone even rings. If your phone doesn’t hear anything, it will hang up. If you can’t find a model of phone that has a built-in call blocker, you can also buy a call-blocking device. These look like little boxes that you connect to your landline, and they do the same thing as a built-in call blocker.

3 Unfortunate Consequences of Unchecked Ghost Calls

Dealing with scammers can be time-consuming and frustrating, so many people and businesses try to ignore the issue and hope it goes away. As tempting as this can be, we don’t recommend it because unchecked ghost calls can sometimes turn into major problems.

Expensive Phone Bills

Whether you’re answering the phone and getting charged for a call you never wanted, or if you’ve got scammers using your phone system to make a bunch of calls you have to pay for, ghost calls can become major financial headaches for you and for your business.

Risks to Your System Security

Ghost calls can pose serious risks to your individual privacy if scammers get access to your data, and they can be even more devastating to a business. If you fall victim to a SIP attack and scammers are able to access your information, they can take over or disrupt devices on your network, use your passwords to steal information, and shut down your ability to make or receive phone calls.

Damage To Your Reputation

If a scammer is able to clone your phone system and make calls while impersonating you, they can seriously undermine people’s trust in your business, making it much less likely that leads or customers will pick up the phone when you call. Once your name or number is associated with a scam, there’s not much you can do to recover that particular number, so you’ll usually have to start over with new contact channels.

Best Practices Going Forward

Bad actors may always find ways to exploit phone systems, so the issue of ghost calling is likely to persist as long as we still use phones. That said, as long as you keep some basic maintenance practices in place, you should be able to keep ghost calls to a minimum.

To protect yourself moving forward, remember to do the following:

  • Recognize ghost calls when they happen and report them to your service provider.
  • Keep all your hardware and software up to date.
  • Use common sense protections like strong passwords and VPNs.
  • Check in with your service provider regularly to see if there are any new recommendations, updates, or security services.