VoIP offers businesses more flexibility and cost savings – but without proper safeguards, it can expose your network to serious risks. A single gap in your VoIP security can open the door to threats like eavesdropping, vishing, and downtime that impact operations across your entire organization.
In this guide, we’ll explore the biggest VoIP security risks and how to protect against them with VoIP security best practices you can use to keep your communications safe.
Is VoIP Secure?
Yes. VoIP can be secure when it’s implemented with the right safeguards.
Unlike traditional phone systems, VoIP transmits voice data over the internet. While this opens the door to web-based threats like eavesdropping, spoofing, or unauthorized access, it also means you can take advantage of proven security protocols that help prevent those risks from becoming problems.
When your VoIP system is backed by features like encryption, user authentication, and proactive monitoring, it can be just as secure – if not more secure – than a landline system. That’s why many organizations partner with providers like Netlink Voice that build security into the foundation of their voice platforms.
Common VoIP Security Risks
Knowing the risks is the first step toward protecting your VoIP system. Here are some of the most common threats today’s businesses face:
Eavesdropping
Eavesdropping occurs when hackers intercept unencrypted voice packets and listen in on calls. This puts your sensitive information, like login credentials or customer data, at risk.
Vishing
Voice phishing (vishing) attacks increased by 442% in 2024,1 fueled by AI-powered deepfake technology that makes it easier to mimic real voices. These calls often trick users into revealing personal information, transferring money, or provisioning access to secure systems.
Call Hijacking
Attackers may exploit signaling weaknesses to take over – or hijack – an active call, allowing them to inject malicious content or reroute the call without users knowing.
Distributed Denial of Service (DDoS) Attacks
A DDoS attack floods your VoIP network with fake traffic, overwhelming the system and making it unavailable for legitimate calls.
Toll Fraud
Toll fraud occurs when an attacker infiltrates a poorly secured VoIP system to make unauthorized international calls and rack up charges that you might not notice until the bill arrives.
Caller ID Spoofing
VoIP systems are susceptible to caller ID spoofing, where a hacker impersonates someone else’s phone number to trick users into revealing private information.
Man-in-the-Middle (MitM) Attacks
In MitM attacks, hackers intercept VoIP traffic between two endpoints. Without encryption, they can listen in or potentially alter the data before it reaches the intended recipient.
VoIP Encryption: How It Works & Why It Matters
A 2025 report revealed that over five million public Wi-Fi networks are unsecured,2 making VoIP encryption more important than ever. Encryption scrambles your voice data so that even if someone intercepts it, they can’t make sense of it.
Common VoIP encryption protocols include:
- SRTP (Secure Real-time Transport Protocol): Encrypts the audio portion of VoIP calls.
- TLS (Transport Layer Security): Encrypts the signaling data that initiates and manages the call.
- ZRTP: Adds end-to-end encryption without needing certificates or key exchanges in advance.
Netlink Voice’s ConnectWare platform includes encryption protocols as standard, ensuring all calls are protected from end to end without requiring additional setup.
8 VoIP Security Best Practices for Businesses
You don’t need to be a security expert to protect your VoIP system. Here are some steps you can take to reduce your risk:
1. Use Encrypted VoIP Protocols
Make sure your VoIP provider supports TLS and SRTP, and that encryption is enabled by default for all calls. If encryption isn’t standard, it’s time to consider switching providers.
2. Segment VoIP Traffic
Use VLANs to isolate your VoIP traffic from other business systems. Segmentation limits threats from impacting your voice services if another part of your network is compromised.
3. Implement Strong Authentication
Use multi-factor authentication (MFA) for system administrators and change default passwords on devices. Weak passwords are one of the most common ways attackers gain access to any system, including VoIP platforms.
4. Deploy Firewalls and SBCs
Session Border Controllers (SBCs) protect VoIP traffic at the edge of your network, while firewalls help filter out unwanted traffic and block known threats.
5. Monitor Call Logs and Set Alerts
Keep an eye on unusual patterns like high call volumes, unknown destinations, or late-night usage. Many VoIP platforms offer tools that can automate this monitoring to cover your systems 24/7.
6. Keep Systems and Firmware Updated
Outdated firmware on VoIP phones, routers, and software clients creates vulnerabilities that hackers can exploit, so make sure to update these systems regularly.
7. Limit International Calling
If your team doesn’t need international calling, disable it at the system level. Limiting access reduces your exposure to toll fraud.
8. Conduct Regular Security Audits
Schedule routine assessments to review your firewall rules, check device configurations, and assess your VoIP security policies at least once per year – or turn to a trusted VoIP provider like Netlink Voice to conduct these assessments and save your team the trouble.
Choosing A Secure VoIP Provider
Not all VoIP providers offer the same level of protection. When evaluating your options, ask these questions:
- Do they support TLS and SRTP by default?
- Is their infrastructure geo-redundant for resilience?
- Do they offer 24/7 monitoring and threat detection?
- Can they integrate with your current security stack (firewalls, SBCs, authentication tools)?
- Have they worked with companies in your industry or compliance environment?
Look for a provider that prioritizes VoIP security at every layer, from the device to the network to the user.
Netlink Voice: Your Trusted Partner for VoIP Security
VoIP is deeply connected to how modern businesses run – from customer calls to team collaboration. But as voice systems become more connected to your broader IT environment, they also become more attractive targets for cybercriminals. A secure VoIP platform can help your organization get ahead of evolving threats so your conversations stay private.
At Netlink Voice, we take VoIP security seriously. Our ConnectWare phone system includes built-in safeguards to keep your calls protected, and we offer proactive monitoring to handle threats before they can impact your business communications.
Ready to secure your VoIP system the right way? Get in touch with the Netlink Voice team to get started.
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