Motherboard just posted an article claiming that T-Mobile, Sprint, and AT&T are selling customer data that ultimately allows individuals to geolocate U.S. phones with nothing but a phone number. Journalist Joseph Cox gave a phone number and $300 to a "bounty hunter," and quickly got a Google Maps screenshot with a relatively accurate location of the phone back. Apparently, major telecommunication providers are selling geolocation "services" to a number of private companies. and those services end up being resold on the black market without their knowledge. The bounty hunter did this all without deploying a hacking tool or having any previous knowledge of the phone's whereabouts. Instead, the tracking tool relies on real-time location data sold to bounty hunters that ultimately originated from the telcos themselves, including T-Mobile, AT&T, and Sprint, a Motherboard investigation has found. These surveillance capabilities are sometimes sold through word-of-mouth networks.... In the case of the phone we tracked, six different entities had potential access to the phone's data. T-Mobile shares location data with an aggregator called Zumigo, which shares information with Microbilt. Microbilt shared that data with a customer using its mobile phone tracking product. The bounty hunter then shared this information with a bail industry source, who shared it with Motherboard.