Robocall prevention

This is a type of fraud detection that’s designed to prevent robocalls. It counts calls from a specific calling number over a 60-minute period. If the number of calls from a number exceeds the trigger threshold, then the software will perform the action you chose during setup: either block the call, divert it to another call handling system (like our CAPTCHA gateway), or complete the call and log it in a report for your review.

Reputation service

This service checks the reputation of the calling number. Many people use smartphone applications and services that provide the ability to report robocalls. This crowdsourcing is used to build databases of robocall caller IDs. When enough people report robocalls from the same calling number, that number eventually acquires a poor reputation.

With the reputation service, you can set up policies that will either block call from a number with poor reputation, divert it, or report only. For example, some carriers have set it up to divert calls from a low-reputation calling number to the customer’s voicemail. Alternatively, you could divert such calls to the TransNexus CAPTCHA gateway, which would prompt the caller to enter a two-digit code. A robocall program would not be able to do that. Legitimate callers would hear the prompt, enter the code, and their calls would be sent through to you..

Blacklist with partial number match to prevent neighbor-spoofing

The whitelist/blacklist service has powerful capabilities that can be used for a variety of purposes. One use is to screen calls when the calling number is like yours.

This trick, called neighbor spoofing, has become common in robocalls. The perpetrator programs the robocalls to construct a fake caller ID that is like your phone number. The perpetrator is hoping that you might be more likely to answer a call from such a number—what if it’s from a friend or family member who’s in trouble and is trying to get through to you? So, you answer the call—anyone might—just as the perpetrator hoped.

You can set up the blacklist to divert such calls to the TransNexus CAPTCHA gateway.

Customer-maintained blacklists

Our software products provide APIs (application program interface) that you can use with your customer web portal to allow your customers to set up their own blacklists. You would need a web portal that authenticates subscribers before they can enter a request to block calls to their number from a specific calling number.

Shield database

TransNexus maintains a database of high-risk numbers compiled from many sources. These numbers include premium-rate numbers, for example, and numbers known to be used in robocalls. You can enable the Shield database service to block, divert or report those calls to protect yourself from robocalls and fraud attacks.

Secure Telephone Identity (STI) using STIR/SHAKEN

Robocalls are like a game of cat-and-mouse. Perpetrators are clever in finding an opportunity, then exploiting it until it gets blocked. Then they move on to another opening and continue. There are many techniques to minimize robocalls, but it has been difficult to completely shut them down.

But there is a way. There’s an initiative called Secure Telephone Identity (STI) that would eventually shut down robocalls completely.

This initiative uses technology like secure internet—HTTPS—with a system of attestation, certified signatures and verification. Sounds complicated, but the internet you use every day has employed technology like this for years.

Secure Telephone Identity would eliminate caller ID spoofing and robocalls.

The telecom version is called STIR/SHAKEN. These James-Bond-inspired acronyms describe a framework where the originating service provider attests to the validity of caller ID information and adds a secure signature. At the other end of the call transmission, the terminating service provider checks the attestation and verifies the signature.

This way, you would know whether the caller ID you see is fake. Robocall perpetrators would not be able to trick you. The terminating service provider might send a call with weak attestation through to you anyway, with an indication that the caller ID cannot be verified. But you might not answer that call. Eventually, robocall perpetrators would find that no one is answering their calls anymore. Game over.

TransNexus has added STI using the STIR/SHAKEN approach to our ClearIP and NexOSS software products. They’re production-ready today.