Business telecoms systems are a frequent target for fraudsters. While cyber attacks often dominate the headlines, telecoms fraud continues to cost organisations thousands of pounds every year through unauthorised calls, compromised phone systems and account takeovers.
The good news is that many telecoms fraud attacks follow recognisable patterns. By understanding the warning signs and putting the right controls in place, your organisation can significantly reduce its exposure to fraud.
What is telecoms fraud?
Telecoms fraud is the unauthorised use of a business’s communications services for financial gain.
Fraudsters typically target phone systems, VoIP platforms or user accounts, using them to make high-cost calls, access services they should not be using or generate revenue through premium-rate numbers. In some cases, organisations only discover the problem after noticing unusual call activity or unexpected charges.
As businesses continue to adopt Cloud telephony and hybrid working, maintaining secure communications infrastructure has become an increasingly important part of managing cyber security risk and protecting business operations.
Common Types of Telecoms Fraud
PBX Hacking
Private Branch Exchange (PBX) systems are a common target for attackers. Once access is gained, fraudsters can use the system to make large volumes of unauthorised international or premium-rate calls, often outside normal business hours.
VoIP Fraud
Voice over Internet Protocol (VoIP) solutions offer flexibility and cost savings, but poorly secured accounts can become vulnerable to attack. Stolen credentials may be used to make fraudulent calls or gain unauthorised access to communications systems.
International Revenue Share Fraud (IRSF)
IRSF is one of the most common forms of telecoms fraud. Attackers generate calls to premium-rate international numbers and receive a share of the resulting revenue, leaving the victim organisation responsible for the charges.
Wangiri Fraud
Wangiri, which translates as “one ring and cut”, involves fraudsters placing missed calls from international or premium-rate numbers. The aim is to encourage recipients to call back and incur high charges.
Warning Signs Your Business Could Be at Risk
Spotting suspicious activity early can help prevent significant financial losses and minimise operational disruption.
Unexpected Increases in Telecoms Costs: A sudden spike in call charges without any clear business reason should always be investigated.
Unusual Call Destinations: Repeated calls to unfamiliar international locations, premium-rate numbers or destinations your organisation does not normally contact can indicate fraudulent activity.
Out-of-Hours Call Activity: Many attacks occur overnight, at weekends or during public holidays when suspicious activity is less likely to be noticed. Unexpected call volumes during these periods should be reviewed promptly.
Unauthorised Account Changes: Unexpected password resets, account lockouts or configuration changes may indicate that an attacker has gained access to your communications environment.
Customer Reports of Suspicious Calls: If customers receive unexpected calls that appear to come from your organisation, cyber criminals may be spoofing your business number.
How to Protect Your Business
Use Strong Authentication: Secure user accounts with strong passwords and enable Multi-Factor Authentication (MFA) wherever possible. This adds an additional layer of protection against unauthorised access.
Restrict Calling Permissions: If international or premium-rate calling is not required, consider blocking these destinations by default.
Keep Systems Updated: Regular software and firmware updates help protect against vulnerabilities that fraudsters may attempt to exploit, reducing the likelihood of compromise.
Monitor Call Activity: Review call reports regularly and configure alerts for unusual activity, including out-of-hours usage and sudden traffic spikes. Early detection helps reduce financial exposure and supports a faster response.
Partner with a Trusted Managed Provider: A trusted managed provider can help implement security controls, monitor activity and identify potential threats before they become costly problems. Managed communications and cyber security services also provide ongoing support to help your organisation maintain a strong security posture.
What Should You Do If You Suspect Telecoms Fraud?
If you believe your phone system has been compromised:
- Contact your telecoms provider immediately.
- Change passwords for affected accounts.
- Review recent call activity and access logs.
- Restrict outbound calling where necessary.
- Conduct a security review to identify the source of the breach.
Fast action can significantly reduce financial exposure and help prevent ongoing misuse.
Telecoms Security Is Part of Cyber Security
Modern telephony platforms are no longer standalone systems. They often connect with business applications, Cloud services and customer data, making them an important part of your wider cyber security strategy.
Like any connected technology, telephony systems should form part of a layered approach to cyber security. Protecting your communications infrastructure helps reduce risk, safeguard business operations and improve resilience against evolving threats.
Protect Your Business Communications
Telecoms fraud remains a genuine threat to organisations of all sizes, but the warning signs are often easy to spot once you know what to look for.
By combining proactive monitoring, strong security controls and expert support, your organisation can significantly reduce the likelihood of becoming a victim of telecoms fraud while strengthening the resilience of its communications environment.
Looking to strengthen the security of your business communications?
SCG’s managed Cloud telephony and cyber security services help organisations reduce risk, improve resilience and support secure, reliable communications. Contact SCG to discover how we can help protect your organisation.
FAQs
Telecoms fraud is the unauthorised use of your business communications services for financial gain. This can include fraudulent international calls, compromised VoIP accounts, premium-rate call scams and unauthorised access to phone systems.
Common warning signs include unexpected increases in call charges, unusual international call activity, out-of-hours usage, unauthorised account changes and reports of suspicious calls appearing to come from your organisation.
Businesses of all sizes can be targeted. Organisations using PBX systems, VoIP platforms, Cloud telephony solutions or hybrid working environments may be at greater risk if appropriate security controls are not in place.
No security measure can eliminate risk entirely. However, organisations can significantly reduce their exposure by using strong passwords, enabling Multi-Factor Authentication (MFA), restricting unnecessary calling permissions, monitoring activity and keeping systems up to date.
Modern telephony platforms often connect to business applications, Cloud services and user accounts. As a result, telecoms security forms an important part of a wider cyber security strategy, helping to reduce risk, protect business operations and improve resilience.