How can you protect your phone system from TDoS attacks and toll fraud?

by Rajesh Haridas, 17 February 2023

TDoS attacks can damage your business. 

The nice part is that TDoS attacks, can be significantly mitigated by planning.

This entails adding enough internal and external protection to the communication system as well as having a well-documented protocol in place to deal with such an event. Most advanced SBCs have features like trusted peers and throttling.

When a distributed TDoS assault is conducted, however, the firm can suffer greatly.

Regional efforts like STIR/SHAKEN can certainly help reduce the harm. However, there are limitations to how such a system can prevent such attacks on a global level.

Some of the recommended TDoS mitigation techniques.

What applies to each environment is determined by the role of telephony in your organization.

A major call center, for example, that is business critical, requires more protection than a telephone system that is a cost center for the company.

SBC Trusted IP: Set your SBCs to only accept traffic from trusted IP addresses and not reply to communication from any other source.

Firewall Protection: Installing firewalls with appropriate configurations can help filter out malicious traffic and protect against TDoS attacks. Despite the fact that firewalls are notorious for disturbing voice communication, a properly configured firewall can be used as an additional line of defense against TDoS attacks.

Load Balancing: Distributing your SIP trunks to multiple servers helps minimize the load on any one server, making a TDoS attack less likely to succeed.

Traffic Management: Limit the volume of incoming traffic to a certain level so that even if an assault happens, the impact is minimal.

Protect your IVR: Add an access-list to your IVR to keep it from dialing expensive destination numbers. Additionally, restrict which numbers are permitted to be dialed for call-back services.

Use a TDoS mitigation service: Several manufacturers offer capabilities to help you safeguard your telephony infrastructure.

Some of the key players are listed below.

Oracle Communications

Ribbon Communications




In conclusion, it's evident that TDoS attacks can significantly harm your business, causing disruption and financial losses.

However, the good news is that with proper planning and mitigation techniques, you can significantly reduce the risk of TDoS attacks.

This includes adding internal and external protection to the communication system and implementing a well-documented protocol to handle such an event.

Some of the recommended TDoS mitigation techniques include SBC trusted IP, firewall protection, load balancing, traffic management, protecting your IVR, and using a TDoS mitigation service.

It's essential to determine which techniques apply to your organization's environment, based on the role of telephony in your organization.

With the right approach and techniques, you can protect your telephony infrastructure and avoid the harmful effects of TDoS attacks on your business.

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