Regardless of the industry, most businesses are heavily dependent on telephonic communication as part of their daily operations. From speaking with customers to sorting out arrangements with suppliers, phone calls are usually the preferred method of communication, and they aren’t going anywhere anytime soon.
Unfortunately, this doesn’t mean that all calls are completely protected against people with malicious intentions, either trying to steal data or intercept calls for their own financial gain. That’s why it’s important to know how these cybercriminals gain unauthorised access to your VoIP system and how you can prevent them from having their foot in the door.
What Is Unauthorised Access to Your VoIP System?
Unauthorised access occurs when an external attacker gains entry to your network to make calls, steal company data, or disrupt your services. Hackers typically look for easy entry points to your VoIP system, such as weak extension credentials or unpatched hardware.
If a breach occurs and goes undetected for an extended period of time, businesses can face significant financial losses very quickly.
What Are the Common Threats to Business VoIP Systems?
Cybercriminals use several different methods to exploit network vulnerabilities. Some of the most common tactics include:
- Toll fraud: Attackers break into your system to make high volumes of expensive international calls, while leaving you with a large phone bill.
- Phishing and vishing: Scammers trick employees into handing over sensitive login details via deceptive emails or fake phone calls.
- Eavesdropping: Individuals who intercept unencrypted audio calls to listen in on confidential conversations.
- Denial of Service (DoS) attacks: Malicious actors bombard your VoIP system with fake calls and messages so that the service slows down significantly or crashes entirely. This then prevents you from taking calls from real traffic.
- Malware infections: Criminals inject malicious software into your hardware to block access or steal data until a ransom is paid.
What Are Some Signs That Your VoIP System Has Been Compromised?
Catching someone who has gained unauthorised access to your VoIP system can save your business lots of money. There are several clues you could look out for to determine whether an intruder might have accessed your phone software:
- Unexpected increase in bills: You might notice a sudden jump in call charges, especially if criminals are dialling premium international numbers over a weekend.
- Strange messages: You or your employees could receive fake antivirus warnings or suspicious texts asking for personal details.
- Decrease in call quality: Audio clarity might suddenly drop, which can indicate that someone is flooding your network with traffic or actively trying to intercept the call.
- Accounts being locked out: Unexplained password changes, browser redirections, or altered voicemail configurations often point to an intruder taking control of your profiles.
How Can You Protect Your VoIP System From Unauthorised Access?
Let’s face it, stopping someone from intercepting calls is much more cost-effective compared to fixing the financial damage that could be caused by a hacker. Luckily, there are a few effective preventative measures you could take to limit the possibility of others interfering with your VoIP system.
Apply Strict Spend and Destination Limits
Capping your financial exposure is probably the most effective measure you could take to prevent severe financial damage. Ask your provider to block premium-rate numbers and restrict outbound international dialling to only the countries you actively do business with.
You should also agree on a hard monthly spend limit that automatically suspends outbound calling when reached, which means that any potential losses are limited.
Enforce Strong Password Policies
Extension passwords are for machines, not humans, so they should be long, random strings rather than simple words. Change any default voicemail PINs immediately, and implement multi-factor authentication (MFA) to add an extra layer of login security to your VoIP system.
Use Firewalls and Session Border Controllers
A standard internet firewall is often not enough for voice traffic. For this reason, implementing a Session Border Controller (SBC) acts as a dedicated gatekeeper for your calls. An SBC monitors all incoming and outgoing connections and automatically blocks suspicious activity before it reaches your internal network.
Encrypt Your Voice Traffic
If your data travels across the internet as plain text, anyone with the right tools can intercept it. You can prevent eavesdropping by enabling Transport Layer Security (TLS) and Secure Real-time Transport Protocol (SRTP).
This scrambles the data into unreadable code, which means that when a cybercriminal tries to listen to your private conversations, it won’t sound like a real discussion to them, and they won’t be able to listen in.
Keep Software and Firmware Updated
When developers discover a security vulnerability within a software, they release a fix, also known as a patch, to the public. Developers then make the public aware of this security flaw, while hackers also read these announcements.
While these announcements allow others to update their software, hackers only see it as an opportunity to interfere with outdated systems. To stop this from happening, update your routers, desk phones, and software applications regularly to ensure you have the latest security patches.
Keep Your VoIP Systems Safe and Secure
It is always better to mitigate risk, than having to put out fires. By having strong passwords, training your staff on the various cyberattacks out there, and keeping your software updated, you can use your VoIP systems with greater peace of mind.
