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Ask HN: How do phone spammers know my location?
9 points by syphilis2 10 months ago | hide | past | web | favorite | 2 comments
For the past month my cell phone has been receiving the same robo call from various phone numbers. This is normal. What's new is that the calling number changes based on my physical location. I took a trip to Massachusetts and the spam calls were Massachusetts numbers. I spent a night in Washington DC and the calls changed to Washington DC area codes. How does the spammer know which phone number to "call" from to match my location? Is this likely a malicious app, are websites tracking my IP address, or is there some other path for spammers to behave this way? How could I even find out how this information is leaked?

You can fairly easily get the current location for a mobile, at least down to a specific country and state.

Basically you pretend that your sending an SMS to the device and the home network will return you some data which includes the serving network, from this data you can guess location fairly accurately.

It’s a little dodgy, some networks will put filtering in place to stop this, but not many bother.

If you want to see it in action here’s somewhere selling the service masked through a basic JSON API - https://www.messagebird.com/en/lookup

It's called "neighborhood" caller ID spoofing and its extremely common and accessible to almost any would-be scammer. It's illegal, but its hard to take enforcement against.


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