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VoIP vs. Landlines: Comparing Security and Vulnerabilities

Kathleen Christie bio
A call center representative talking to a client after learning about VoIP security.
In my years working with telecommunications, I've seen firsthand how security can make or break a system.

As of 2023, the average cost of a data breach reached $4.45 million. This statistic shows just how important it is to choose secure communication devices.

VoIP systems are cheaper and have more features but depend on the internet and may face cyber threats. On the other hand, traditional landlines are more stable and less prone to hacking but lack advanced functionality and can be more expensive.

In this post, I'll compare both technologies' strengths and weaknesses to help you choose a secure and effective communication tool for the modern digital world.

» Which is better for your business? VoIP vs. landline phones.

What Are VoIP Vulnerabilities?

VoIP calls are transmitted over the internet in packets. Like other internet technologies, these parcels are susceptible to a range of issues, including:

  • Weak or stolen usernames and passwords
  • Back doors
  • Application vulnerabilities
  • Poor access control
  • Unencrypted connections
  • Data breaches

Cybercriminals and scammers can exploit these weaknesses to hack phone systems, spread malware, and conduct various attacks, such as Distributed Denial of Service (DDoS) attacks and vishing (voice phishing).

How to Enhance VoIP Security

To secure your VoIP line, you must:

  • Encrypt your VoIP calls by using a virtual private network
  • Implement strong passwords across your virtual PBX systems
  • Enable Network Address Translation (NAT) to mask your IP address
  • Monitor your VoIP network
  • Disable phone web interface and international calling
  • Close port 80 (commonly used for loading web pages) with a firewall

» Learn how to use your cell phone as a VoIP phone.

What Are Landline Vulnerabilities?

Landline phone calls are transmitted using circuit switching—a process where a dedicated path is established between the caller and the recipient. This circuit remains exclusive to the session until one of the parties disconnects.

Despite traditionally being considered more secure than VoIP, landlines have their own security vulnerabilities. These include:

  • Susceptibility to damage or tampering
  • Vulnerability to wiretapping
  • Challenges in integrating with smart technologies
  • Limited mobility

How to Secure Your Landline

To improve your landline's security, you should:

  • Use end-to-end encryption
  • Implement voice scramblers at both ends of a conversation
  • Apply physical security measures such as protecting wires from being tapped
  • Monitor for any physical tampering
  • Set secure voicemail passwords
  • Regularly maintain and inspect the landline infrastructure
  • Train users how to recognize and respond to landline communication threats

VoIP vs. Landlines: Eavesdropping and Call Interception

Since VoIP calls are sent over the internet, they're easier to intercept. VOMIT (Voiceover Misconfigured Internet Telephones) poses an additional risk. This threat allows hackers to convert conversations into files and access private information and critical business data, like passwords, usernames, call logs, and financial details.

To counteract these dangers, VoIP providers have adopted robust encryption and strong authentication protocols and run regular software updates. These measures significantly enhance the security of VoIP calls, making them less vulnerable to interception and unauthorized access.

In contrast, eavesdropping on landlines requires physical access, typically through a terminal box outside buildings. Landline systems also have security measures in place, but the nature of the technology inherently limits the risk of remote eavesdropping. Although more challenging than intercepting VoIP, it remains a potential threat.

VoIP vs. Landlines: Caller ID Spoofing and Vishing

VoIP systems are easy targets for vishing, where cybercriminals pose as trusted entities, like banks, to extract important customer data. These invasions can lead to breaches of secure systems and sensitive business information.

VoIP is also at risk of caller ID spoofing. Attackers can mask their identity during a call to spread malware, steal information, or bypass security controls. You should report these incidents to the Federal Trade Commission (FTC) and Federal Communications Commission (FCC) immediately.

Since VoIP systems come with more advanced features, you have access to enhanced user authentication and caller ID verification technologies. Providers also educate users about the risks of vishing to reduce the likelihood of these violations.

Landlines face different challenges. A common issue is phone number spoofing, where hackers mimic your number to access your voicemail—especially if it's not protected by a password. Your messages may contain personal or sensitive information, which criminals can use to impersonate you or commit fraud.

Landlines can also be hit by impersonation attacks. During these incidents, scammers can use social engineering tactics to trick unsuspecting employees into giving away sensitive data or business login credentials, leading to unauthorized access to systems and networks.

» Keep your communications private with these 10 VoIP security best practices.

VoIP vs. Landlines: DoS, DDoS, and SIP-Based Attacks

VoIP systems are extremely vulnerable to DDoS attacks. In such raids, cybercriminals flood servers with excessive data and requests, exhausting the bandwidth. This results in a complete halt in VoIP operations, significantly disrupting business activities.

Additionally, VoIP faces threats from Session Initiation Protocol (SIP)-based attacks. Here, assailants target trusted SIP networks, sending fake IP requests to initiate unauthorized calls, further compromising VoIP safety.

However, VoIP systems include advanced DDoS mitigation tools and strong network infrastructures. Your provider also updates your security protocols continuously. With these measures in place, you can detect and manage excessive traffic to ensure uninterrupted service delivery—even during a raid.

Although landlines can also be affected by DoS attacks, the method differs. These incursions aim to make the telecom service temporarily unavailable to its users. While less frequent than high-profile website invasions, DoS attacks on telecom systems can severely disrupt communication services.

VoIP vs. Landlines: Malware, Toll Fraud, and Phreaking

Any data or application on the internet is at risk of malware injections—VoIP is no exception. Malware can infiltrate the VoIP grid, consuming bandwidth and degrading call quality. Worse, it can give hackers access to the entire business network, leading to data theft and other malicious activities.

But, VoIP providers can counter these hazards by implementing advanced malware protection, ensuring network segmentation, and conducting regular security audits. Additionally, these operators use intrusion detection techniques and real-time monitoring to swiftly identify and respond to any signs of malware activity.

Toll fraud is another risk for VoIP users. Scammers can exploit phone lines and services to make unauthorized high-volume calls, often to international or premium-rate numbers. This can disrupt communications with genuine customers and clients.

To combat this, VoIP solutions use sophisticated fraud detection systems that monitor and flag unusual call patterns. Plus, they enforce call barring and spending limits to prevent high-volume unauthorized calls.

Phreaking attacks also specifically target VoIP systems. Cyber pirates can break into the VoIP network to make calls, alter calling plans, or add credits, causing monetary losses for the account holder.

Still, internet calling service providers can strengthen your defenses with authentication and access controls. Additionally, they regularly update their systems to patch any vulnerabilities, protecting you from financial setbacks and making sure their services stay reliable.

Make the Secure Choice

While it's true that VoIP faces certain risks like eavesdropping and cyber attacks, you can manage these challenges with the right security steps. Landlines may be typically less vulnerable to digital raids, but they don't have as many features as VoIP.

The most secure VoIP services, like RingCentral or Vonage, can give you access to robust security features. In fact, 94% of small businesses say their safety improved after they started using cloud-based services. This level of protection, combined with the advanced functionalities of VoIP, makes it an attractive option for your business.

» Find out how VoIP phone services can transform your business.

Kathleen Christie bio
Kathleen Christie, a Top10 writer, specializes in call center development and telephony operations. She's skilled in Avaya provisioning, IP Telephony, Modular Messaging, Microsoft Suite, and Telecom Expense Management, along with Training, Leadership, Customer Service, and Problem Resolution.