VoIP Services VoIP Security: The Ultimate Guide to Encryption and Vulnerabilities

VoIP phone systems, being cloud-hosted innovations, incorporate several security infrastructures, such as call encryption, two-factor authentication, and SaaS.

Yet, they can be prone to cyberattacks, such as Phishing, Phreaking, Spam Over Internet Telephony (SPIT), Black Hole and Packet Sniffing, etc.

But implementing some security measures, such as end-to-end encryption protocols and following the preventive tips below, can reduce exposure to VoIP risks.

Keep reading to discover the importance of VoIP security, some critical security vulnerabilities, and the best practices to secure your VoIP business system.

VoIP seurity all explained

The Importance of VoIP Security

VoIP is a web-associated technology that deals with information transmission (data, voice, etc.) from one person to another.

Security in such technology is vital to protect information from hackers, dark web players, etc.

If a VoIP system is not secured, hackers can extract users’ data like contact details, full name, card details, etc., and use these to dupe them. 

But with security protocols like end-to-end encryption, it’s difficult for fraud to occur.

Besides fraud prevention, security in VoIP brings privacy and confidentiality. Most individuals prefer using names or contact details different from their real identities. With data privacy, they can keep their sensitive information confidential.

Also, technological developments like Voice Cloning AI and Professional AI Text Writers are emerging, making it easier for scammers to manipulate information and impersonate individuals.

So, by integrating advanced security protocol in VoIP, there would be fewer risks from cyber attackers reducing losses, especially for small businesses.

What Happens Without VoIP Security?

In the early evolution of VoIP, security was the minor attribute considered, and many businesses, tiny startups, faced increased losses to cyberattacks yearly.

The majority of breaches on credit cards were on small businesses, costing the businesses and their customers around $15.4 million every year.

So, neglecting VoIP security means more losses across the businesses using the system, increasing the lack of trust from potential customers.

But by implementing strict VoIP security measures like end-to-end encryption for both calls and texts, there would be fewer vulnerabilities in the VoIP space.

What is Encryption in VoIP?

Encryption in VoIP is the process of disorganizing voice data packets into hard-to-read formats while transmitting them across the internet to a recipient.

For instance, a VoIP phone calls a number for a conversation, and the voice data scrambles into packets and are sent across the internet. 

Before it reaches the call destination, the packets are reassembled as playable audio, enabling the recipient to hear the message in audio data.

So, even though a hacker tries bypassing the call, this encryption protocol will deny them access, and any information they get is unusable.

To better understand encryption in VoIP, let’s explore the transmission procedures.

When voice data packets transit from the caller to the recipient, they utilize an IP transport protocol, SRTP (Secure Real-Time Transport Protocol).

This applies the Advanced Encryption Standard (AES) to the packets, providing message verification while offering extra confidentially against potential replay threats.

It also employs another encryption that secures the call information, like the caller and recipient’s details: Transport Layer Security (TLS). Thus, shielding phone numbers, usernames, callers’ names, and other information.

This means VoIP works with AES and TLS encryption to provide reliable data privacy across VoIP systems.

Does VoIP work with End-To-End Encryption?

With the increased need for VoIP security, end-to-end encryption is now a key security protocol available in many VoIP systems.

Unlike TLS encryption which uses client-to-server (C2S) encryption, the end-to-end (E2E) encryption directly encodes communication between VoIP users. As such, only individuals that can access messages and calls are the recipients and senders.

Unlike C2S encryption, which stores unencrypted data on a server, E2E encryption only decrypts data as soon as they reach the recipients.

Thus, hackers cannot manipulate, eavesdrop, or even record calls from the connection. Apart from hackers, individuals like telecom providers, ISPs, or servers will not access users’ communication due to end-to-end encryption.

To enhance users’ security and data privacy, many VoIP providers adopt this end-to-end encryption, making their services reliable and less vulnerable.

Critical VoIP Security Vulnerabilities and Prevention

VoIP security does not guarantee 100% protection from security threats on your devices, including IP desktop phones, softphones, or smartphones.

However, knowing the most common security risks and preventing them can help protect your business and your customers.

Here are the most common vulnerabilities of VoIP security and excellent tips to prevent them:


This kind of attack is called Vishing because it deals with VoIP phishing. This is the malicious act of making phone calls or using voice messages to scam customers, posing to be a real agent of a certain business just to get vital information from them.

Vishing attackers are usually after vital information, such as passwords, card pins, etc., to dupe the customers.

The scammer might instruct the customer to forward their credit card pin for a bank account upgrade online, as coming to the office could be stressful.

Like phishing, scammers keep false websites or send fraudulent emails to customers, posing themselves as trustworthy only to acquire the customer’s personal information.

Some examples of phishing scams are:

  • IRS scam.
  • Fake promises of loans or support.
  • Medicare scams, etc.

Tips to Prevent

  • Organizations, even bank personnel, will not request sensitive or personal information via phone calls or text.
  • When an organization calls you requesting such information, be careful and take your time.
  • If scammers call, they tend to hurry or threaten, adding a sense of urgency to the issues and claiming to represent well-known and reputable firms.
  • Use third-party scam detector apps like True Caller to protect yourself from Vishing. Also, once you suspect anything fishy, hang up and reset your details like passwords, transaction pins, etc.


A phreaking attack is a cybercrime where fraudsters break into your telephone networks, make calls with your details, access your calling plans, and do other activities that will be charged to your account.

They can steal stored billing details, reconfigure routing and call forwarding patterns, and even access users’ voicemails.

These hackers will call your phone system and input a PIN code that grants them access to outside lines, enabling them to make calls at your expense.

Tips to Prevent

  • You may be facing a phreaking attack once you notice unexpected bills on your VoIP phone system or an increase in unknown numbers.
  • To best prevent this attack, encrypt every SIP trunk, change the passwords to your accounts, and buy ransomware security software.
  • More importantly, don’t save your billing information while making payments on the system.

Black Hole and Packet Sniffing Attacks

This attack entails hackers stealing and logging unencrypted data in voice data packets during transmission.

As a result, voice data packets get missing without reaching their destinations because the hackers are sniffing them, looking for information to steal.

This attack also makes the service slow, causing the packets to drop (the black hole attack).

Additionally, packet sniffing simplifies the interception of usernames, passcodes, and other vital information for hackers.

Tips to Prevent

  • An ideal prevention for black hole and packet sniffing attacks is using a reliable virtual private network (VPN) to share information on your VoIP system.
  • Although setting up might take a little time, it’s a perfect solution for securing your information. Also, ensure that all your data is E2E encrypted while implementing constant network monitoring.
  • This way, you’ll notice suspicious activities on unfamiliar devices, login attempts, etc.

Spam Over Internet Telephony (SPIT)

SPIT is the unwanted distribution of calls or voice messages across IP-based interaction mediums like VoIP.

It’s more like telephony spam that involves automated systems, flooding recipients with unsolicited calls or pre-recorded messages for malicious purposes.

As an automated spam attack, SPIT uses bots or computers to transmit several calls and messages to thousands of VoIP users at the same time. 

Tips to Prevent

  • Some ways to prevent Spam Over Internet Telephony attacks include enabling call blocking and spam filters on the VoIP system. Moreover, be careful when giving out your details online.

Toll Fraud

Toll fraud attacks occur when an unauthorized individual (mostly hackers) gains access to a communication system like VoIP, making costly international (long-distance) calls billed to the system’s owner.

Besides billing you for their calls, hackers can make money off toll fraud. Here’s how; International Premium Rate Number Providers (IPRN) purchase and resell numbers from country regulators or carrier groups. 

Hackers who make many calls through those international numbers get paid via the IPRN.

Tips to Prevent

  • You must enable two-factor authentication on the system and your accounts to prevent this kind of VoIP security risk. Also, set geo-permission restrictions to allow users to contact selected countries.
  • Furthermore, limit your rates to specific call duration and permission on concurrent calls.

Voice Over Misconfigured Internet Telephones (VOMIT)

This attack is a hacking tool that converts conversations into playable files, making extracting information from VoIP business phone systems less difficult.

Besides eavesdropping, VOMIT can allow hackers to source business information like call origin, usernames, passwords, bank details, and phone numbers.

Tips to Prevent

  • To prevent a VOMIT attack on your VoIP system, consider migrating to a cloud-powered VoIP provider, as they encrypt calls before transmitting them to recipients.

Man-in-the-Middle (MITM) Attacks

MITM is an attack where the hacker fixes himself in the middle of a VoIP network and the intended destination of a call.

One of the major causes of this attack is connecting to unsecured or public Wi-Fi networks. Hackers can intercept and reroute calls using their servers instead, enabling easy infection of malware, viruses, and spyware.

While detecting this kind of attack can be tricky, authentication attempts or tamper detention tools can be used, even though they don’t always work.

Tips to Prevent

  • One of the ways to prevent MITM attacks is by implementing solid WAP/WEP encryption on key access points. This improves router login details with a VPN, etc.

Viruses and Malware Attacks

Viruses and malware in your computer or mobile device where your VoIP service is connected can expose it to potential hackers.

When there’s a virus in your device, it consumes more network bandwidth, increasing signal congestion. 

As a result, the signal breaks down and corrupts data in transit across your VoIP system, causing packet loss.

In this process, they create backdoors that hackers can access to steal or tamper with call information.

Tips to Prevent

  • Preventing viruses and malware will entail the application of data security strategies like network infection examination and encryption.
  • While some routers automatically block malware and even dangerous sites, implementing software and hardware firewalls that are compatible with VoIP can enhance security on the system.

Distributed Denial of Service Attacks

DDoS is an attack that restricts businesses from using their VoIP services due to clustered servers.

Distributed Denial of Service occurs when thousands of botnets, remote-controlled hacker computers, flood servers, websites, and even networks with unattainable requests.
Once the servers are overloaded, they malfunction, locking several VoIP services out with slowed service, 503 HTTP error responses, or unusual bandwidth increase.

Tips to Prevent

  • To prevent DDoS from affecting your VoIP systems, use VoIP-dedicated internet. Alternatively, go for Virtual Local Area Networks (VLANs) as they provide exceptional network solutions for VoIP systems.
  • It can also detect unfamiliar and unauthorized data flows, helping you know when botnets are manipulating the network.
  • Meanwhile, if you share VoIP across wide area networks (WAN), consider managed encryptions for more protection from DDoS.

Call Tampering

While call tampering may look like a minor cyberattack, it can ruin call quality, spoiling the communication experience between businesses and customers.

Call tampering attacks occur when hackers input irrelevant noise packets into call streams, making the call spotty. It caused long silences and made rings look garbled.

Tips to Prevent

  • VoIP users can prevent call tampering using end-to-end encryption with TLS as the data packets authenticator. They can also adopt an endpoint detention tool for enhanced data protection.

Things to Do to Avoid VoIP Security Issues

How to avoid VoIP security issues

Even though there are various ways to prevent the security mentioned above risks, it’s advisable to avoid activities that could attract such attacks.

Consider some of them below: 

  • Don’t use public Wi-Fi.
  • Adopt an unguessable password policy.
  • Always run security audits like patching, app-based scanning, cyberattack simulations, firewall configurations, and gateway assessments.
  • Run regular system and software updates.

Now you’ve known the security vulnerabilities of VoIP and the best practices for their issues, let’s explore some tips to learn about the security of a VoIP provider.

Tips to Pick a Secure VoIP Provider

If you want to know a secure VoIP provider, do these:

  • Review their Status page to learn about their historical system outages, upgrades, network issues, and uptime.
  • Look out for the technical support team, where you can report any issues and monitor their response rate. They should be responsive and ready to resolve any complaint.
  • Confirm if the provider is PCI, HIPAA, and GDPR compliant. This shows that the provider runs with certified security protocols.
  • Carefully read the About Us and Privacy Policy page of the provider. You’ll learn how they collect and use your data on their sites.

With these in mind, you can quickly locate the most encrypted and secure VoIP provider for your business communication needs.


VoIP security is 100% important for businesses and individuals to prevent Vishing, DDoS, MITM, Virus, Malware attacks, etc. 

Some VoIP providers are ahead of others regarding encryption and strict security, making it tricky to know the best choice.

However, you can consider them based on key security measures like end-to-end encryption, HIPAA and SOC 2 compliance, ISO-27001 Certification, and many others.


Can VPN protect VoIP systems?

How do I secure my Wi-Fi Connection?

What are the most secure VoIP providers to consider?

Susan Laborde Tech Writer

Susan Laborde Tech Writer

Susan Laborde researches the latest technology trends in an ever-changing tech landscape to provide comparisons, guides, and reviews that are easy to understand for readers. When taking a break from being a tech word wizard, she plays games with her baby.

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