Ask HN: How do Robocallers know where I’ve been? | Hacker News Reader

Ask HN: How do Robocallers know where I’ve been?

13 pointsxigency6 comments

Hey all,

Looking through my missed calls, I see I’ve gotten 18 spam calls in the last week. At this point I’m quite disappointed with both Verizon and the FCC.

What’s particularly concerning is that it seems spam callers are somehow aware of my location. Last month I traveled out of state to Texas. Since then about half of the calls are from TX area codes.

Has anyone else noticed a similar phenomenon? I know there’s nothing I can do at this point but silence unknown numbers and change my voicemail to the tone for a disconnected line.

It’s quite absurd how the telecom industry has let things progress to this point. I don’t see how it could lead to anything but a negative impact on their business from such a terrible customer experience.

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There is actually a lot of sketchy ways cell towers and the cellular network in general is being used today due to the how the architecture was set up long ago and the current FCC administration.

What you are seeing is a common tactic, these spammers know you are more likely to pick up a number that is most similar to yours and they buy the data of recently connected phones from cell towers through aggregators.

You might find this podcast on the whole thing interesting:

https://gimletmedia.com/shows/reply-all/awhk76

Many apps share your location data with aggregators, who combine it with your IP address, device ID, credit card purchase history, and literally thousands of other details about you. While this profile is nominally "anonymized," in that it doesn't have your name and address directly in the record, it very clearly relates to an individual person.

The aggregate data is sold far and wide, and not difficult to obtain. Scammers and others buy these profiles in bulk, and then mine them for potential customers to call in the same way that "legit" advertisers use your profile to decide which ads to insert in your Hulu stream or on top of your smart TV program.

When I moved states several years ago, the spam callers were mostly choosing DIDs from my immediately local area within a few months of having moved. This isn't new.

Wild guess, geolocation data collected from a phone, either from an app or even from normal website visits where the visitor can be identified and their ip address geolocated. Cross referenced with the phone number when queueing numbers into the auto-dialer, to choose an appropriate fake callerid. I wouldn't rule out the cellular carriers providing such a service themselves, but seems trivial to do with or without a carrier's assistance for data brokers. They could even make their usual bogus claims of anonymization, if an api accepted only a phone number, and only returned general loosely recent location information like city/state/county.

Perhaps a variation of another suggestion. The trick being that you're likely to answer similar (presumably local) numbers. However, a simpler explanation is that they have a pool of numbers and call you from the one with the prefix most similar to yours.

> However, a simpler explanation is that they have a pool of numbers and call you from the one with the prefix most similar to yours.

This doesn't work if you just traveled to Texas since your number wouldn't have changed.

Do you happen to have an Android or iPhone with an app installed? Perhaps they could be getting your location and phone number there?

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