Voice over Internet Protocol (VoIP) is a communications technology that enables voice and multimedia messages over the Internet. Due to advantages such as low cost, mobility, scalability and flexibility, the use of VoIP has exploded in recent years.

VoIP also carries security risks, such as the possibility of unauthorized access, eavesdropping and fraud. Therefore, it is essential to ensure the security of VoIP systems.

In this article, we list 9 VoIP security risks and give you tools to prevent or mitigate these vulnerabilities. Use it to your advantage!

The 9 most common VoIP security risks and how to solve them

What vulnerabilities does a VoIP system have? We list them below.

1. DDoS attacks

One of the best-known VoIP security risks is a DDoS attack. In a distributed denial of service (DDoS) attack, cybercriminals intentionally flood a server with data and consume all the bandwidth. When all server bandwidth is used up, VoIP activity (and all other Internet activity!) comes to a halt.

Disruptions like these can have serious consequences for a company’s daily operations and bottom line.

Unfortunately, DDoS attacks are becoming increasingly common. The equipment needed to carry out a DDoS attack is becoming increasingly sophisticated, making it cheaper and faster for cybercriminals to carry out these attacks.

A survey by Corero found that 70% of organizations experience about 20-50 DDoS attacks per month.

According to security firm Cloudflare, the average cost of a successful DDoS attack is about $100,000 per hour.

What should you do in the event of a DDoS attack?

First, it is important to identify DDoS attacks early. Because the sooner you can recognize a problem, the sooner you can work on a solution, right? Make someone responsible to take action as soon as your company is attacked.

Once the attack begins, there are several steps you can take to limit the damage:

  • Increase your bandwidth limit: While having spare bandwidth for emergencies is unlikely to nip a DDoS attack in the bud, it can give you the precious time you need to contact security experts.
  • Notify your ISP: If you suspect your business is under attack, contact your ISP immediately. They can help you limit the damage and solve the problem.
  • Limit the damage: consider isolating the affected system to prevent it from compromising the rest of the network or other systems.
  • Engage a DDoS specialist: DDoS attacks can be complex and you may need the help of a specialist to solve the problem. A DDoS specialist can help you analyze the traffic and identify the origin of the attack.

2. Vishing

Vishing – as the name suggests – is phishing via VoIP. Just as e-mail phishing scams attempt to obtain sensitive financial information from victims through e-mail links, VoIP vishing scams attempt to obtain this information through voice mail messages.

How do you solve this?

The best method to protect yourself from vishing scams is to verify all incoming call requests, even if they appear to originate from your organization. In addition, your employees should be trained not to provide sensitive information to anyone without the express permission of their supervisor.

3. VoIP fraud

VoIP fraud happens when hackers break into your VoIP system and use your services without permission. Fraudsters often use toll fraud, artificially generating many international calls to premium numbers and reaping the profits. This can cost you a lot of money and often you don’t notice.

How do you solve it?

There are several ways to protect yourself from VoIP fraud. Here are some tips:

  • Offer international calling services only to customers who request them.
  • Set time-based spending limits for your international calling service plans.
  • Monitor usage outside office hours and investigate if necessary.
  • Enter into shared liability contracts with your customers so that you do not pay for the costs if VoIP fraud occurs.


Voice over Misconfigured Internet Telephones, or VOMIT as it is delightfully called, poses one of the biggest VoIP security risks.

Hackers use this method to listen in and extract voice packets directly from ongoing calls, giving them access to sensitive information such as call origin, usernames and passwords and financial data.

How do you solve it?

To solve this problem, it is advisable to use a VoIP service provider that automatically encrypts incoming and outgoing calls. Steam-connect not only encrypts your incoming and outgoing traffic, but you also use a private PBX so you can be sure your calls are secure.

5. Call Tampering

Tampering in phone calls happens when cybercriminals send a lot of data over the call path or slow down the transmission between callers. This causes poor connections and silences in the conversation, which can be detrimental to businesses that make a lot of phone calls.

How to fix it

As with previous situations, it is important to contact your Internet Service Provider (ISP) and inform them of the situation. Then you need to create a plan to protect your telephone operations from such breaches. Increasing authentication and encryption efforts can help with this.

All voice traffic entering and leaving your call center should be encrypted and IP phones should have authentication codes during idle hours. These are good security practices that in general can help drastically reduce the frequency of call tampering in your call center.

6. VoIP network firewalls

If this question has you scratching behind your head, we don’t blame you: firewalls are usually a good thing. But in the case of VoIP, only the most modern firewalls are compatible with VoIP protocols, and older firewalls are subject to VoIP security risks. Older firewalls do not recognize VoIP activity and may block some core functions of your call center.

How do you solve it?

It’s simple: make sure you purchase a modern firewall system. Up-to-date firewalls will certainly improve rather than weaken your security.

7. Malware and viruses

Malware and viruses are a constant threat to all networked systems, including VoIP systems. They are particularly harmful because they allow cybercriminals to gain access to the entire system. In this way, criminals can steal sensitive information, use network bandwidth and easily reduce call quality.

How do you solve it?

To prevent malware and virus attacks, it is important to think ahead. Develop a plan for regular security audits, implement security protocols throughout the company, and make sure your employees adhere to company-wide security measures. By properly protecting your business from security threats, you can prevent malware and viruses from doing harm.


Another beautiful abbreviation. SPIT stands for Spam over IP Telephony. SPIT is similar to e-mail spam, but for VoIP. At SPIT, automated systems send massive pre-programmed voicemail messages or robocalls, hoping that unsuspecting people will pick up the phone and listen to the messages.

If this happens, you may face unexpectedly high phone charges, which the scammers use to their own advantage.

9. Dated systems

If you don’t regularly update your VoIP system’s software, you run the risk of becoming vulnerable to security threats. Technical administrators sometimes forget to update cloud-based VoIP systems because analog phone systems didn’t need to in the past. While understandable, this can cause significant damage to your business in the long run.

How do you solve this?

The solution to keeping your VoIP software safe is to update it regularly. You can do this by scheduling periodic checks and discussing updates during quarterly reviews. It is important to be consistent and keep doing this over and over again for a secure VoIP network.


VoIP systems can be vulnerable to a variety of VoIP security threats, from SPIT attacks and outdated software to malware infections. It is important for companies using VoIP technology to take the necessary steps to protect their networks.

This includes regularly updating your system’s software, implementing authentication protocols, encrypting all traffic entering or leaving your call center and purchasing modern firewalls compatible with VoIP protocols.

With these simple measures, you can ensure the security of your company’s voice communications while preventing malicious parties from accessing sensitive information stored on your network.

When you purchase VoIP from Steam-connect, your data is optimally secured. We use the best European data centers and monitor 24/7. As a Steam-connect customer, you can sit back and relax knowing that your communication channels are in good hands. Knowing more? Download our brochure.