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Complete guide to VoIP cyber security

Updated: Jan 6, 2023

What are VoIP cyber security risks?

VoIP communication is carried out over the Internet and can be the target of all cyber attacks. Many threats, such as malware, phishing, and packet sniffing, can threaten your company's communications infrastructure.

1. DDoS attacks

DDoS attacks aim to keep companies' VoIP services busy. There will be heavy traffic, and companies cannot use VoIP services. Company resources are consumed in a short time, and calls start to be delayed. In a very short time, the financial loss grows.

DDoS attacks are carried out with remotely controlled computers. These computers are used to create a network called a "botnet." An attacker attacks a specific IP address by issuing commands to computers in the botnet network.

What to do against DDoS attacks: A separate internet connection should be used for VoIP traffic. Also, encryption and a virtual private network can be used for VoIP.

2. Voice phishing

Voice phishing is also called vishing for short. In this cyber attack method, an unsuspecting identity is used. The target is phishing on VoIP-based networks. The scammer makes his job easier by pretending to be legitimate.

Voice phishing attacks are different from other cyber attacks. Because you can't leave detecting unusual caller ID entirely to your VoIP security system. When the attackers obtain sensitive information, they reach their goal.

What to do against voice phishing: Ask the other person for proof of identity to avoid voice phishing attacks. Also, pay attention to the language the attacker uses.

3. Spam over IP technology

Spam over IP technology is called SPIT for short. These are unsolicited voice messages sent over the VoIP system. While voice messages are delivered as spam, they also come with risks of malware or other cyber threats.

VoIP accounts are assigned to a specific IP address. Spammers are usually located in a very different country than the attacked network. They hide real phone numbers and make calls to VoIP addresses. When they get an answer, they reach their goal.

What to do against spam over IP technology: It is impossible to be protected entirely from SPIT attacks. However, it's a good idea to use a firewall and SBC.

4. Toll fraud

Toll fraud refers to the unauthorized use of long-distance services. The attacker infiltrates a compromised VoIP system. So, this system allows making international calls using various devices. Thus, he begins to generate income.

The attacker, who wants to generate income from the toll fraud attack, achieves his goal by calling premium rate numbers. The attack can be successful even if only one device is vulnerable in the VoIP system. Then, the attacker can make money for a long time.

What to do against toll fraud: A password policy and two-factor authentication should be enabled for all devices. Also, limits should be set for simultaneous calls.

5. Phreaking

The word phreaking is a combination of the words phone and freak. It refers to the use of audio frequencies to manipulate VoIP phone systems. In this way, attackers change their calling plans, allowing you to bear the costs.

Phreaking attacks have methods such as accessing voice messages and call forwarding. They ensure that their calls are covered by your account. You may be a phreaking victim if there are too many unknown numbers in call history.

What to do against phreaking: The best practice to avoid phreaking attacks is regularly changing account passwords and using robust security software.

6. Malware threats

Malware is the most serious problem threatening VoIP networks. Since VoIP is an internet-based solution, issues such as rapid bandwidth consumption may be encountered. As a result, VoIP calls are disrupted, and the quality of service decreases.

In attacks with malware, attackers may try to gain access to private information. They try to create a backdoor for themselves by infecting the network with a virus. Then, they sneak into your network and collect sensitive company data.

What to do against malware threats: Regular network audits and the use of SBC are a must. Security measures should be stepped up to ensure data security.

7. Packet sniffing

Packet sniffing is an approach that is subsequently manipulated and falls into the category of cyber attacks. It was typically developed to examine the quality of telephone lines. However, it is now used by attackers to save unencrypted data.

The packet sniffing method is concerned with preventing the audio data packets from reaching their destination. Attackers deliberately slow down the network and cause disconnections. Then they accomplish their data theft goals.

What to do against packet sniffing: Reliable VoIP systems and VPN should be used. By using end-to-end encryption, you can keep company information secure.

8. War dialing

War dialing is a process that is carried out by calling a large number of phone numbers, regardless of the target. It is essential to use computer software to perform the method. The software is given lists of obtained numbers, and calls are initiated.

When the attacker detects a phone with a security breach, it tries to enter the VoIP system. After entering the system, the attack begins to fulfill its target. This is generally an attempt to consume the search credits of the company entered into the system.

What to do against war dialing: The simplest solution to war dialing is to disable unused devices. Strong passwords should be created if devices must remain active.

Best practices for VoIP cyber security

You must follow some security steps to protect your VoIP network against cyber attacks. You have a very low chance of recovering your losses due to VoIP fraud. That's why you need to protect your company's VoIP network.

1. Disable web interface

The web interface of VoIP devices is actually handy. Here you can find any settings you want to edit. However, not every company takes much responsibility. Weak passwords used to log in to the interface and more can become a problem.

The most important assistant for someone who wants to attack the VoIP network will be the web interface of the devices in the system. Disable the web interface if you don't want to deal with interface and device control.

2. Disable unnecessary services

The biggest target of people attacking VoIP networks is to make money by making use of international calls. If international calls are not required by your company, disable them. Thus, you significantly prevent attackers from achieving their goals.

If your company is going to make international calls over VoIP, you should take the necessary security measures. A session border controller (SBC) is one of the most effective solutions. It's a good idea to constantly check what's going on in your network.

3. Enable NAT

Enable NAT, which ensures that the IP address of your VoIP devices is only visible on the LAN. NAT masks the IP address, creating a layer between devices and the Internet. It prevents attackers from manipulating with remote access.

When creating a VoIP network for your company, you should choose devices with NAT support. With NAT disabled, it's pretty easy to keep devices busy with fake calls. Enable NAT to keep your IP addresses private.

4. Use strong passwords

Devices on your VoIP system with default passwords. These passwords can be easily accessed by doing a short internet search. You should change the default passwords and use strong passwords to protect your VoIP network.

You should restore the device to its factory settings if you have purchased a new device to connect to your VoIP network. Then you should change the default password. You should also ensure that each device has a unique password.

To create a VoIP network for your company, you should consider every detail, from phone calls to phone numbers. You must protect your reputation, credits, and budget by protecting your network from attackers.

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