Top VoIP Related Cyber Threats, and Their Solutions, Companies Must Know

Advantal Technologies
4 min readApr 3, 2021

A VoIP (Voice over Internet Protocol) is a software application, or softphone, that facilitates phone calls over the internet. Hiring VoIP development services for digitalization sidesteps leased lines by routing straight into the PSTN (Public Switched Telephone Network). These softphone programs, or digital phones, help organizations to:

  • Enhance productivity,
  • Improve efficiency and flexibility, and
  • Reduce cost.

The Power of VoIP

VoIP applications give you tremendous advantages. Aside from your set monthly VoIP bill, there is no connectivity charge or cost associated with VoIP services. It also means that no additional cost for long-distance, as it doesn’t matter where the call is going over the World Wide Web.

An efficient VoIP software application will have an easy-to-operate, user-centric design. These apps also handle the call-routing in a network; even provide flexibility to authorize a mix of company-owned and employee-owned devices.

Thus, with the power of VoIP, you can obtain cost-efficiency, flexibility, and ease of operations.

With Great Powers, Comes Great Responsibility

VoIP has a solid reputation for being a safe and reliable technology. That said, if you use computers or the internet, it’s imperative to be aware of the associated security threats and necessary precautions.

Vishing (Voice + Phishing)

Vishing is a fraudulent technique where a hacker uses false credentials to trick call receivers into giving up confidential data. It is just like Phishing, where a fraudulent email seems authentic but has malicious intentions. But in vishing, instead of emailing, the hacker calls the target victim.

Often, the hackers in such cases may have some details on you, which give a false sense of confidence for their credibility. It can lead the agent to disclose sensitive information to the hacker.

Solution: Companies can mitigate vishing attacks to a great extent. Agents who are authorized to receive calls should verify the identity of a caller. Agents should also be instructed not to reveal classified details until they first received permission from their superiors.

Denial of Service (DoS)

A hacker inducts a blast of SIP call-signaling messages to block the VoIP network bandwidth. Denial of service, or DoS, often results in the halting of call processing and leads to premature VoIP call drops. It can not only hamper your business operations but also can let hackers have access to system administrative tools.

Solution: To reduce the impact of the DoS attacks, companies should separate data and voice traffic. You can use a VPN or encryption (if using WAN) to diversity the network. Alternatively, you can keep two dedicated separate connections and keep one dedicated to VoIP clients.

Using a VLAN, or virtual LAN, provisioned for VoIP calls, is also a good idea. It can also help you to discover unauthorized data flows and take timely action.

Call Tampering

Call tampering is a cyber-attack in which a hacker tries to degrade the clarity of your calls. The intention is to cause inconvenience or disrupt your business processes. Hackers do it by inserting noise packets into the data path.

Solution: You can keep hackers at bay by using proper authentication and data encryption. You can also use SIP (Session Initialization Protocols) to authenticate initiation, sustaining, and termination of real-time VoIP sessions. When you go for reliable VoIP development services, they find innovative and sophisticated solutions for security beforehand.


Eavesdropping means hackers intercept call streams to listen to the conversations. They gather sensitive information to commit identity theft and gain free access to your VoIP network. Cybercriminals who eavesdrop are known as phreakers as they phreak through VoIP networks to acquire access.

Phreakers can misuse this sensitive information to cause the company harm, or they can use the access to make numerous calls on your bill.

Solution: Sophisticated authentication system can prevent identity theft. Your VoIP development services can help you with it. Although flexibility is a boon, restricting access to fewer trustworthy IP addresses is a good security measure. You can set up parameters to block IP addresses that have a certain number of failed log-in attempts.

Man in the Middle

Man-in-the-Middle (MITM) attack is a type of eavesdropping where the attacker injects himself into the communications channel, often between two trusted parties. MITM invaders can also use malware to infiltrate the communications channel. They can create zombie machines to eavesdrop and gather sensitive data and trade secrets.

Solution: Use firewalls, the latest anti-malware applications, and Wi-Fi Jammers to prevent a man-in-the-middle attack.

Train your employees on the dynamics and patterns of MITM attacks. Your training module should include case studies for quicker identification and decision-making during an actual invasion.


Making a VoIP system secure is more complicated than securing a straight data network. However, the advantages outweigh the risks if proper protocols and procedures are in place. Most of these threats, like phreaking and tampering, are also present in the traditional telecommunication setup.

Therefore, ask VoIP development services to digitize your calling operations with proper security measures. Also, a little bit of staff training on cybersecurity can go a long way.



Advantal Technologies

Advantal Technologies is a leading software development company that builds software for large firms and SMEs to enhance online productivity.