VoIP systems, undeniably, offer more benefits to businesses than the traditional phone system. From its versatility, seamless communication, customer service ease to increased productivity, VoIP is the future of business communication. 

But is VoIP secure?

In this guide, we’ll cover what VoIP security and encryption means, how it works, types of VoIP security threats, what you can do to prevent them, and other security best practices.

What is VoIP Security and Encryption?

VoIP encryption is the process of modifying voice data packets into unreadable clutter while they are in transit, preventing them from being deciphered if intercepted by hackers.

VoIP security is the level of trust and safety of the voice call data transferred over a business communication platform.

How Does VoIP Encryption Work?

Data Encryption protects sensitive information and ensures that even if data gets intercepted by hackers, they will not decipher it.

VoIP encryption works using the SRTP (Secure Real-Time Transport Protocol) that applies the Advanced Encryption Standard (AES) to data packets, providing call authentication, and protection against attacks. 

In addition, Transport Layer Security (TLS) or SIP over TLS is also used to protect call information. 

Why is VoIP Security Important?

VoIP security is a necessity because of the increased rate of cybercrimes. According to CNBC, over half of small businesses suffer from data breaches and cyber-attacks every year. Cyber attacks also have serious financial implications. The average cost of a data breach was $3.86 million in 2021. Even if all of your data is backed up and restored, you may still have to deal with a damaged perception that could later financially affect your business.

Types of VoIP Security Threats and How to Prevent Them

There are varying threats to take note of when using the VOIP; here are they and how to prevent them:

Packet Sniffing and Black Hole Attacks 

Packet sniffing and black hole attacks happen when hackers intercept voice or call data in transit and steal information that is not encrypted. This information can include usernames, passwords, and other sensitive data. 

To prevent packet sniffing and black hole attacks, use a reliable VoIP VPN option, ensure all data is end-to-end encrypted and monitor your network consistently for any suspicious activity.

DDoS Attacks

DDoS (Distributed Denial of Service) attacks occur when a vast network of botnets i.e.,, remotely-controlled computers/bots, render your VoIP useless by overwhelming your servers with more loads of connection requests than you can manage.

Common signs of a DDoS attack include traffic surge from similar devices or IP addresses, 503 HTTP Error Responses, and Slowed service. To prevent DDoS attacks, use VLANs (Virtual Local Area Networks) which are networks dedicated to handling just VoIP.


Vishing or VoIP phishing happens when a hacker pretends to call from a trusted source with the intent of making you reveal sensitive information such as passwords, credit card details, etc

To prevent vishing attacks: 

  • Do not provide sensitive information over the phone to anyone claiming to be the IRS, Medicare, or Social Security Administration. 
  • Do not respond to voice prompts via voice answers

Malware and Viruses

Malware and viruses damage programs that cause signal breakdown for your VoIP calls by consuming network bandwidth and corrupting data transmitted across your network.

To prevent malware and viruses, use VoIP-compatible software and hardware firewalls that scan information to ensure it’s secure, use encryption, and regularly check the network for unusual activities.

Phreaking Attack

A phreaking attack lets hackers make calls and charge the bills to you. They break into your VoIP system, access your call and billing information, change calling plans and make as many phone calls as they want.

To prevent a phreaking attack, encrypt all SIP trunks, change passwords frequently, buy ransomware protection software, and do not store billing information in the system. 


Spam over IP Telephony (SPIT) is a security threat where spam prerecorded voice calls with the intention of phishing are sent on VoIP phone systems. These spam calls are also associated with viruses and other malicious attacks.

To prevent SPIT attacks, have a firewall that helps identify the spam and quickly takes care of it before it overwhelms your system.

Toll Fraud

Toll Fraud is similar to a phreaking attack, but hackers make these voluminous calls to get part of the revenue the calls generate. This revenue is taken from International premium rate number (IPRN) providers that buy and resell phone numbers from country regulators. 

To prevent toll fraud, enable two-factor authentication on your accounts, have geo-restrictions, and set limits on concurrent calls and call duration. 

Call Tampering

Call tampering is when a hacker drops noise packets into the call stream, preventing packets from being delivered to their proper destination. This damages call quality and frustrate communication. 

To prevent call tampering attacks, enable end-to-end encryption, use TLS to authenticate data packets, and use endpoint detection software. 


VOMIT (Voice over Misconfigured Internet Telephones) is a VoIP hacking tool that eavesdrops on conversations, siphon information, and converts them into files that can be used anywhere. 

This eavesdropping can access data such as usernames, passwords, bank details, call origin, and phone numbers from your system. To prevent VOMIT, use a cloud-based VoIP provider that encrypts calls before they are sent.

VoIP Security Best Practices

Try out these practices to help maximize the VOIP phone system:

Implement a strong password policy

It is not unusual that hackers make attempts to guess passwords. Instruct your staff to change their passwords weekly. They should not use the same passwords for multiple accounts and avoid using information that can be easily guessed, like a pet’s name but use a combination of letters, numbers, and non-alphanumerics.

Keep your operating systems up-to-date

Many VoIP providers run automatic software updates. However, it is still recommended to check if you are using the latest version. Beyond feature improvements, updates contain relevant security updates and protection against viruses and malicious software.

Set up a VPN for all your remote staff

VPNs hide your IP address, location, and more from your Internet Service Provider and the websites you visit. It encrypts all traffic and allows your remote staff to browse the Internet anonymously. 

Enable WiFi encryption

Ensure you’re using proper WiFi encryption protocols. Out of the top three encryptions – Wired Equivalent Privacy (WEP), WiFi Protected Access (WPA), and WiFi Protected Access Version 2 (WPA2), WPA2 is the best choice.

Enable WPA2 on your company’s WiFi networks. Ensure your employees also use this encryption for their Wi-Fi network. Also, remember to update your Wi-Fi password regularly.

Review your call logs frequently

Check your company’s call logs to see any unusual call traffic or activity. Use the call analytics feature on your dashboard to get the weekly and monthly insights. 

Remove inactive accounts

When employees leave, remove their accounts. It is not advisable to leave VoIP accounts inactive without a real user to avoid unwanted access to intruders. 

Perform frequent security checks

Frequent security checks ensure you do not have network lapses that can impact VoIP call quality and security. In addition, these security checks should be carried out by independent, external security agencies to ensure no stone is left unturned and to take appropriate preventive actions.

Avoid using public a WiFi

Instruct your employees to avoid using public WiFI on work devices. One of the worst ways to be vulnerable to a cyber-attack is through public, unsecured WiFi, as it is a nesting ground for viruses and malicious software.

VoIP Security FAQs 

Here are three of the frequently most asked questions on VoIP security:

How secure are VoIP calls?

As secured as the VoIP providers make them. VoIP system providers ensure that your sensitive data are safe from any hacking attempts through the safety measures built into their platforms. They also provide security updates and scan regularly for weaknesses.

Can VoIP be hacked?

Yes. Like any device connected to the Internet, VoIP phone systems can be targeted by hackers to gain access through insecure internet connections. 

How to tell if your VoIP provider is secure?

You can tell if your VoIP provider is secure from the answers they give to the questions below: 

  • What is the guaranteed uptime, and what do you do to minimize downtime? 
  • How long does it take to respond to a security attack and restore safe service?  
  • What security certifications do you have? Are you GDPR, HIPAA, and PCI compliant?
  • How do you encrypt your data, and does that encryption impact call quality? 
  • What customer support is available, and what are the support hours?

Once you have successfully answered these questions, then you can determine how secure the provider is. For more VoIP-related questions, check out our article about 20 of the most frequently asked questions about VoIP.


Like any other cloud-based phone system, VoIP must be checked consistently for potential security risks. This ensures you are well protected and ready in case of an attack. Remember to keep your operating systems up-to-date, use strong passwords, enable WiFi encryption, never share any sensitive information through an unsecured network, avoid using public WiFi and review your call logs frequently.