CBP Tapped Into the Online Advertising Ecosystem To Track Peoples’ Movements(404 Media)

This404 Media article looks at how the US Customs and Border Protectionagency (CBP) is using location data from phones to track the location ofpeople of interest.

Specifically, CBP says the data was in part sourced via real-timebidding, or RTB. Whenever an advertisement is displayed inside anapp, a near instantaneous bidding process happens with companiesvying to have their advert served to a certain demographic. A sideeffect of this is that surveillance firms, or rogue advertisingcompanies working on their behalf, can observe this process andsiphon information about mobile phones, including theirlocation. All of this is essentially invisible to an ordinary phoneuser, but happens constantly.

We should note that the minimal advertising shown on LWN is not deliveredvia this bidding system.