VoIP Fraud: How to Protect Against Phishing Attacks

You might want to know how to protect against phishing attacks to protect yourself from scams. But you’ll especially want to protect against phishing attacks if you own a business. The more employees and devices you have working for you, the more opportunities there are for data breaches. 

As a business owner, it is your responsibility to protect your business data and reputation. You are also responsible for the information of your employees, customers, and clients. Understanding VoIP fraud and how to protect against phishing attacks can save you lots of time, resources, and energy.

What Is VoIP Fraud?

VoIP stands for “Voice over Internet Protocol”. So VoIP fraud refers to illegal activities or schemes aimed at exploiting vulnerabilities in VoIP systems for financial gain or malicious purposes. Since VoIP systems transmit voice communications over the internet, they can be vulnerable to various types of attacks. Here are some common forms of VoIP fraud:

Toll Fraud

Hackers can gain unauthorized access to a VoIP system and make long-distance or international calls at the expense of the system owner. These calls can be routed through premium-rate numbers controlled by the fraudsters who then collect a portion of the fees.

Phishing

As the term “phishing” is typically associated with fraudulent emails and traditional telephone scams, VoIP call attacks are sometimes referred to as “vishing”. Attackers can use VoIP systems to impersonate legitimate entities—banks, customer service representatives—and trick victims into providing sensitive information such as credit card numbers or passwords.

Call Injection

Fraudsters can also exploit security holes to insert fake calls or reroute calls to unintended recipients. This can lead to financial losses or information leakage.

Call Spoofing 

Spoofing is when scammers fake caller ID information. VoIP numbers are easy to spoof because users can choose how they appear on caller ID and choose their area code. Attackers can therefore manipulate the caller ID to disguise their identity, making it appear as though the call is coming from a trusted source. This is often used in phishing attacks or other scams.

Traffic Pumping (Access Stimulation) 

Some fraudsters set up call centers in locations where they can generate high call volumes to premium numbers. These calls are often fraudulent or unnecessary, but they generate revenue for the fraudster via call termination fees.

Denial of Service (DoS) Attacks

In these situations, attackers flood a VoIP system with excessive traffic, causing it to crash or degrade performance. This can disrupt legitimate communications and cost businesses in downtime and repairs.

Fraudulent Account Creation

Criminals can also create fake accounts with VoIP service providers, often using stolen credit card information, to make calls without paying. These accounts are used for criminal activities like illegal telemarketing or scam operations.

VoIP fraud can lead to significant financial losses, damage your company’s reputation, and expose sensitive data. To prevent it, businesses and individuals using VoIP services should implement security measures such as encryption, firewalls, strong passwords, and monitoring tools.

How to Protect Against Phishing Attacks that Use VoIP

Fortunately, there are specific measures you can take to protect against VoIP attacks. VoIP systems can be vulnerable to various security threats, such as unauthorized access, phishing/vishing, and call spoofing. Implementing the following best practices can help safeguard VoIP systems from these threats:

Secure Network Architecture

Securing your business’s network architecture might include isolating VoIP traffic, configuring the firewall, and using virtual private networks (VPNs). 

You can use virtual LANs (VLANs) to separate VoIP traffic from other network traffic. This reduces the chances of attacks affecting other parts of your network. Configure firewalls to restrict access to VoIP services, only allowing authorized traffic. Firewalls should be designed to understand Session Initiation Protocol (SIP) and Real-Time Protocol (RTP) to inspect and filter VoIP traffic. And, secure VoIP traffic over VPNs for remote or mobile users to protect communication from eavesdropping.

Encrypt VoIP Communications

Transport Layer Security (TLS) and Secure Real-Time Transport Protocol (SRTP) are encryption protocols that help protect VoIP signaling and media traffic from eavesdropping, man-in-the-middle attacks, and tampering. Implement end-to-end encryption where possible, ensuring that voice data is encrypted from the source to the destination.

Implement Strong Authentication and Control Access

Design and implement strong password policies. Use strong, complex passwords for VoIP system accounts, especially administrative accounts. Change default passwords immediately upon installation.

Enable two-factor authentication (2FA) for system administrators and users to make it more difficult for attackers to gain unauthorized access. Limit access to VoIP servers and devices based on IP addresses by using access control lists (ACLs) to block traffic from unknown or unauthorized IPs.

Detect and Prevent Intrusion

Implement intrusion detection systems (IDS) or intrusion prevention systems (IPS) to monitor VoIP traffic for abnormal patterns such as unexpected call volumes or unauthorized access attempts. Use tools to monitor call patterns and detect signs of toll fraud or unauthorized usage. Set up alerts for unusual call activity like calls to premium-rate numbers or high-cost destinations. And configure rate limits on the number of calls that can be made or received within a certain time frame to prevent abuse or toll fraud.

Conduct Regular System Updates and Patching

Apply patches promptly. Regularly update your VoIP system software, including firmware for phones and gateways, to address known vulnerabilities. Stay informed about new vulnerabilities in VoIP systems and protocols by following security advisories from vendors and security organizations.

Prevent Denial of Service (DoS) Attacks

Use VoIP-aware firewalls. Firewalls with VoIP-specific security features, such as session border controllers (SBCs), can help prevent DoS attacks by filtering malicious traffic before it affects the VoIP system.

Limit SIP requests, too. You can configure the system to limit the number of SIP requests (e.g., REGISTER, INVITE) per second, helping to mitigate the impact of DoS attacks.

Secure SIP Trunks

Use secure connections with SIP trunk providers, ensuring that all communications are encrypted and properly authenticated. Ensure that SIP devices authenticate before establishing a connection, reducing the risk of unauthorized use of your VoIP service.

Monitor and Log Activity

Enable logging of all VoIP system activities such as calls made, configuration changes, and access attempts. Regularly review and audit logs for suspicious activity. Use analytics to track calling patterns and detect anomalies that could indicate fraud or security breaches.

Restrict International and Premium-Rate Calls

Disable international calling if it isn’t needed. If your organization does not require international calling, disable this feature to prevent toll fraud. Furthermore, block calls to premium-rate numbers or destinations known for high toll fraud rates.

Physically Protect Devices

Ensure that physical VoIP devices such as phones and gateways are located in secure environments to prevent unauthorized access or tampering. VoIP servers and infrastructure should also be housed in secured facilities with controlled access to prevent physical tampering.

Establish and Adhere to Vendor Selection and Security Standards

Choose to work with reliable vendors. Select VoIP service providers and equipment vendors with strong security practices and a track record of patching vulnerabilities. Make sure your VoIP system complies with security standards such as Payment Card Industry Data Security Standard (PCI-DSS) or Health Insurance Portability and Accountability Act (HIPPA) if applicable.

Perform Regular Security Audits

Perform vulnerability assessments. Regularly test your VoIP infrastructure for security vulnerabilities using penetration testing or other vulnerability assessments. Conduct periodic audits of your VoIP system configurations, ensuring that best security practices are being followed and no outdated or insecure settings are in place.

Implementing these measures helps to secure VoIP systems against a wide range of potential attacks, ensuring the privacy, integrity, and availability of your communications.

Now You Know How to Protect Against Phishing Attacks and Avoid VoIP Fraud

By combining education, technology, and cautious behavior, individuals and organizations can significantly reduce the risk of falling victim to phishing attacks. 

You can’t tell a VoIP number just by looking at it. It follows the same 10-digit format as any other number. But you can use a phone validator to identify the line type of a number that’s calling you or that enters your database. A reverse phone number lookup also works the same way for VoIP numbers as it does for any other line type. Similarly, a batch append tool can provide you with associated names, addresses, and emails addresses regardless of the line type.

Want to know more about VoIP numbers? Here is Everything You Need to Know! And remember, understanding VoIP fraud is the first step in how to protect against phishing attacks.