As businesses rely more heavily on technology to streamline their operations and communicate with customers and clients, the importance of cybersecurity cannot be overstated. One area of vulnerability that is often overlooked is the Private Branch Exchange (PBX) system. PBX systems, also known as phone systems, allow companies to manage their internal and external phone calls, voicemails, and other telecommunication services. Traditional PBX systems are hardware-based and located on-premises, while modern PBX systems are often cloud-based and offer more advanced features such as virtual extensions, call forwarding, and voice-over IP (VoIP) capabilities. These systems are critical to many businesses as they enable communication with customers, clients, and employees, facilitating sales, customer service, and internal collaboration. However, PBX systems can also be vulnerable to cyber threats, which can result in severe consequences such as data breaches, financial loss, and damage to reputation.

In this article, we will explore the cybersecurity risks associated with PBX systems and discuss ways that companies can mitigate those risks to protect their sensitive information and maintain business continuity.
One of the main cybersecurity risks associated with PBX systems is unauthorized access. Hackers may attempt to gain access to a company’s PBX system to make unauthorized calls, eavesdrop on conversations, or disrupt services.
In 2019, a cybercriminal group known as “Evilnum” targeted financial institutions using a phishing campaign that tricked employees into clicking on a malicious link, which led to the compromise of the company’s PBX system and used them to make unauthorized calls to premium-rate numbers, resulting in millions of dollars’ worth of charges for the targeted companies.
Companies can take several steps to mitigate the cybersecurity risks associated with PBX systems. First, it is essential to keep PBX system software and hardware up to date with the latest patches and updates. Vendors often release patches to address known vulnerabilities, and it is crucial to apply them promptly to protect against potential cyber threats. Additionally, it is essential to change the default usernames and passwords of PBX systems to strong, unique credentials to prevent unauthorized access. Many cyber-attacks on PBX systems are a result of weak or default credentials being exploited.
If possible, implement multi-factor authentication (MFA) for accessing PBX systems. MFA adds an extra layer of security by requiring users to provide additional authentication factors.

Companies should also configure PBX systems securely by disabling unnecessary features, such as remote access or call forwarding, if they are not required. Regular monitoring of PBX system logs can help detect any suspicious activity or unauthorized access attempts. Implementing strict access controls and limiting the number of users who have administrative privileges to PBX systems can also minimize the risk of unauthorized access. Where possible, companies should also encrypt communication between PBX systems and endpoints to protect against eavesdropping and interception of calls.
If the risks associated with PBX systems are not properly mitigated, various types of data can be compromised, including:
- Call logs: PBX systems store call logs, which contain information about incoming and outgoing calls, including phone numbers, call duration, and timestamps. Unauthorized access to call logs can reveal sensitive information about communication patterns, customer interactions, and business operations.
- Voicemail messages: PBX systems often include voicemail functionalities that allow users to leave and retrieve voicemail messages. Voicemails may contain sensitive information, such as customer inquiries, order details, or confidential business discussions. If unauthorized individuals gain access to voicemail messages, they can potentially listen to or delete voicemails, leading to privacy breaches and business disruptions.
- Call recordings: Some PBX systems have call recording capabilities for quality assurance, training, or compliance purposes. Call recordings may contain sensitive information, such as customer payment details, personal information, or business negotiations. Unauthorized access to call recordings can result in privacy violations and legal liabilities.
- User credentials: PBX systems typically require usernames and passwords for authentication. If user credentials are compromised, attackers can gain unauthorized access to the PBX system, allowing them to make unauthorized calls, eavesdrop on conversations, or disrupt services.
- Financial information: PBX breaches can also result in financial loss, particularly in cases of toll fraud, where attackers exploit vulnerabilities to make unauthorized long-distance or international calls, resulting in excessive phone bills for the targeted company. This can lead to significant financial losses and disrupt business operations.
PBX systems can pose cybersecurity risks to businesses if not properly secured. The compromise of PBX systems can result in data loss, financial loss, reputational damage, and business disruptions. Therefore, it is crucial for companies to implement appropriate security measures, such as keeping PBX systems up to date with patches and updates, using strong and unique credentials, disabling unnecessary features, implementing multi-factor authentication, and monitoring system logs. By proactively mitigating these risks, companies can safeguard their sensitive information and maintain the confidentiality, integrity, and availability of their PBX systems.
Further, much of the data stored by PBX systems could be accessed once the equipment is decommissioned. It is critical to work with an IT Asset Disposition (ITAD) specialist to ensure that all data is wiped from the device. This includes all credentials and access information, as well as any voice recordings, rendering any stored information completely inaccessible and preventing unauthorized access to your networks, your customer, or other confidential information.
Contact Sipi Asset Recovery for your data destruction needs. www.sipicorp.com/itad