Bad actors continue to target vulnerabilities in non-top carriers’ networks

Top US telecom providers (Verizon, UScellular, T-Mobile, Lumen, Comcast, Charter and AT&T) continue to make progress in maximizing the benefits of STIR/SHAKEN implementation, according to Transaction Network Services (TNS) 2025 Robocall Investigation Report. The report, released today, shows that 86% of all traffic between these tier-1 carriers was signed throughout the year, helping to protect their subscribers from unwanted robocalls.

Furthermore, 95% of call traffic between those top carriers was signed with “A level” attestation. This enables the operators to establish SIP-to-SIP connections between originating and terminating parties, preventing robocall bad actors from infiltrating tier-1 networks.

However, despite tier-1 carriers’ positive momentum, the percentage of signed calls between non-top carriers fell by nearly 25% in 2024. Robocall bad actors have exploited these providers' reliance on legacy TDM circuits — and the dropping of the original STIR/SHAKEN information — to hide malicious, unwanted robocall traffic.

“Top carriers deserve praise for their implementation of STIR/SHAKEN, which has enabled them to consistently sign traffic with high attestation levels,” said Seth Walton, TNS’ General Manager, Communications Market. “However, that has not stopped bad actors from launching unwanted robocall campaigns. Non-top carriers’ networks remain at serious risk, and they must prioritize network transformation to limit SIP disruptions. By fully modernizing and transforming SIP-to-SIP connectivity, the telecom industry will be in a stronger position to neutralize robocall threats and protect their subscribers.”

The latest edition of TNS’ Robocall Investigation Report highlights several new robocall insights and trends to inform carriers, regulators, policymakers and the telecom industry on what to expect in 2025:

AI-Generated Robocalls Make National Headlines

In 2024, bad actors increasingly used AI-generated robocalls to exploit and defraud Americans. According to TNS survey data, 73% of US adults were concerned about AI-generated deepfake robocalls that mimic the voice of a loved one to try to scam them out of money, while 51% received or knew of someone who received an AI-generated deepfake robocall.

Political Robocall Volume Soars

Political robocalls surged in 2024, particularly in the final ten days before the election, as robocall bad actors aggressively targeted voters in swing states like Arizona, Michigan and Wisconsin.

TNS observed that the top political robocall scams included fake voter registration, campaign donation requests, and misleading claims that people can vote over the phone.

Robocalls Pose An International Challenge

The global rise of AI deepfakes presented challenges in combatting scams internationally. In the 2024 Indian election, AI-deepfakes and generated voices were created to engage with voters who spoke a different language than the candidates. Other top global robocalls included seasonal scams such as tax preparation, fake medical insurance schemes and educational institution scams, which occurred in the United Kingdom, Australia, Slovakia, and India.

For the first time, the TNS Robocall Investigation Report will be translated completely into Japanese, Italian, and Spanish. Request a copy of the full report for complete access to TNS’ robocall data and insights.

About TNS:

TNS, a market leader in call analytics and robocall mitigation, provides an end-to-end ecosystem for protecting and restoring trust in voice. TNS addresses the full needs of wireless and wireline operators globally with TNS Call Guardian® the industry-leading call analytics solution that protects subscribers from high risk and nuisance robocalls. In addition, its Enterprise Branded Calling solution is the core component of its Identity Analytics Suite that is taking the next step in enriching consumer engagement, making voice calling an integral part of an omnichannel customer experience program. TNS analyzes over 1.5 billion call events across more than 500 operators every single day, enabling carriers to identify more unwanted robocalls. For additional information visit: https://tnsi.com/resource-center/communications/.

View source version on businesswire.com: https://www.businesswire.com/news/home/20250204868187/en/