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What is ANI Trolling (ANI Trawling)?

February 27, 2020
A hacker using ANI trolling as a fraud vector in the IVR

ANI trolling (also known as ANI trawling) is an emerging fraud vector that involves fraudsters running thousands of spoofed phone numbers through a business’s IVR (interactive voice response) system in order to identify which numbers belong to customers of that business. Once the hackers have identified which numbers belong to customers, they launch targeted SMS phishing or smishing attacks on the individuals who own those numbers.

How ANI trolling/ANI trawling works:

When a consumer dials into a call center, it’s common for a call center to try and recognize/match the ANI (automatic number identification) of the caller. If the ANI is recognized, indicating that the number is on file as belonging to a customer, the caller can be given a “green path/fast lane”. If not recognized, the caller is taken down another, more generic path (typically security questions).

Armed with the knowledge about how this works, fraudsters will run thousands of numbers through a given IVR. In the process of doing that, they can identify which numbers belong to customers (based on the path that each number is routed through). When they’ve identified the numbers that belong to customers, they can then take those numbers and buy personal data (name, address, SSN, DOB, etc.) on the black market for them in order to run targeted smishing attacks.

How Payfone helps protect IVRs against ANI trolling/ANI trawling:

Instead of using ANI matching as a decision point, call centers can use Payfone’s ANI match + call authentication to detect whether a call is being spoofed. Then they can set up the decision path such that spoofed calls always go down the generic path, regardless of whether the ANI is matched or not. That way, fraudsters can’t identify which numbers belong to customers/account holders, and therefore cannot carry out SMS phishing attacks on those individuals.

Want more info about how Payfone prevents ANI trolling? Get in touch with us below to learn more.