by Chuck Sharman

A recently revealed FBI report provides detailed instruction to law enforcement on snooping through cell phone data, often without a search warrant, while also delving into similarly warrantless mining of social media sites for personal data.

Obtained via a Freedom of Information Act request by the nonprofit group Property for the People, the 2019 report was produced by the FBI Cellular Analysis Survey Team (“CAST”). Its “Cellular Analysis and Geo-Location Field Resource Guide” provides a 139-page handbook that reminds law enforcement officers around the country what cell phone data can be obtained only with a search warrant, such as the content of text messages or a “trap and trace” of all the numbers with which the phone has exchanged calls.

But the document also offers guidance on how to ask cell phone carriers for data that can be obtained without a court order. A simple subpoena, for example, will produce a list of calls someone’s phone made to a specific destination or to a particular time. The FBI report even provides helpful reminders to note the first numbers called in the morning and the last ones at night.

A subpoena will also suffice to obtain a person’s online activity using cellular data, including IP addresses of any websites accessed and payment information for any purchases made. In addition, cops can pinpoint the whereabouts of someone they are interested in with the help of location data for a specific number at a particular time. After that, another warrantless request can obtain “dumps” from nearby cell towers of all the numbers that it handled at that time. 

CAST even has a free computer tool for law enforcement to plot the data on a map so that cops can visualize a person’s movements. Called CASTviz, the program “has the ability to quickly plot call detail records and tower data for lead generation and investigative purposes.” But the report also provides instructions on using Google Earth to collate locational information, including that which can be gleaned from license-plate readers or even from simply knowing someone’s Social Security number.

A surprising element from the report is the revelation of how long cell phone providers retain a user’s data, including call records, cell sites accessed, and any tower “dumps” the user’s number appeared in. Verizon holds onto this information for a year, T-Mobile for two years, and AT&T for seven years.

What about people who don’t use one of the big three carriers but instead rely on a “mobile virtual network,” like Boost Mobile? Or what about those using prepaid “burner phones” with limited identifying data attached to them? And what about other mobile data, such as that obtained by General Motors’ “On-Star” navigation system? Not to worry—the report provides instructions on getting data in each one of those instances, too.

It also notes that social media sites are another source of information where a warrant is not needed. Facebook, for example, will provide “basic subscriber info” in response to a subpoena. If that turns up sufficient evidence to convince a judge there is probable cause for a search warrant, the social media giant will then cough up photos, private messages, and a list of friends of the person who is targeted.

A cell phone provider can deny some “exigent” requests, the report admits, in which a demand for data asks that it be immediately handed over. But that denial can be overridden by someone in a state’s Attorney General’s office with a rank of assistant deputy or higher.

With nearly 83 percent of Americans using a cell phone in 2020, every one of them should be aware that any sense of privacy over a cellular network is probably overblown and maybe even illusory. Caveat utilitor—let the user beware.

Sources: Reason, Vice, Statistica

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