Sunday, November 26, 2023

Data Analytical Services (DAS)

Dell Cameron and Dhruv Mehrotra (Hacker News):

A little-known surveillance program tracks more than a trillion domestic phone records within the United States each year, according to a letter Wired obtained that was sent by US senator Ron Wyden to the Department of Justice (DOJ) on Sunday, challenging the program’s legality.

According to the letter, a surveillance program now known as Data Analytical Services (DAS) has for more than a decade allowed federal, state, and local law enforcement agencies to mine the details of Americans’ calls, analyzing the phone records of countless people who are not suspected of any crime, including victims. Using a technique known as chain analysis, the program targets not only those in direct phone contact with a criminal suspect but anyone with whom those individuals have been in contact as well.

The DAS program, formerly known as Hemisphere, is run in coordination with the telecom giant AT&T, which captures and conducts analysis of US call records for law enforcement agencies, from local police and sheriffs’ departments to US customs offices and postal inspectors across the country, according to a White House memo reviewed by Wired.

Via John Gruber:

The information collected by DAS includes location data.


This is related to the entire U.S. phone system infrastructure — the old Ma Bell. Landline calls and calls from Verizon and T-Mobile cellular customers get routed through this AT&T system, and are thus surveilled by this same system.


It is completely unclear to me whether DAS/Hemisphere collects text messages — SMS, MMS, RCS — in addition to voice calls.


Publicly disclosed for the first time in September 2013 by the New York Times, the Hemisphere program provides police access to a database containing call records going back decades, combined with a sophisticated analytical system.


“Hemisphere” came to light amidst the public uproar over revelations that the NSA had been collecting phone records on millions of innocent people. However, Hemisphere wasn’t a program revealed by Edward Snowden’s leaks, but rather its exposure was pure serendipity: a citizen activist in Seattle discovered the program when shocking presentations outlining the program were provided to him in response to regular old public records requests.

But these documents only painted a partial portrait of the program, and since the New York Times’ initial reporting in 2013, EFF has filed its own Freedom of Information Act and state-level public records requests to learn more. The results have been frustrating, with various agencies providing highly and inconsistently redacted documents in what seems to be an attempt to further hide information from the public.

Via John Gruber:

This slide deck hosted by the EFF is one of those presentations, and worth your attention. The system’s capabilities are terrifying. From page 9 of that deck, highlighting Hemisphere’s “Special Features”:

  • Dropped Phones — Hemisphere uses special software that analyzes the calling pattern of a previous target phone to find the new number. Hemisphere has been averaging above a 90% success rate when searching for dropped phones.

  • Additional Phones — Hemisphere utilizes a similar process to determine additional cell phones the target is using that are unknown to law enforcement.


So the system analyzes not just the phone records of the target, but the records of every single number the target calls.

Jessica Lyons Hardcastle (Hacker News):

According to Senator Ron Wyden (D-OR), these searches “usually” happen without warrants. And after more than a decade of keeping people — lawmakers included — in the dark about Hemisphere, Wyden wants the Justice Department to reveal information about what he called a “long-running dragnet surveillance program.”


Privacy advocates including the Electronic Frontier Foundations have filed Freedom of Information Act and state-level public records lawsuits to learn more about the secret snooping program.


Although the program and its documents are not classified, the Justice Department has marked them as “Law Enforcement Sensitive,” meaning their disclosure could hurt ongoing investigations. This designation also prevents the documents from being publicly released.


Additionally, Hemisphere is not subject to a federal Privacy Impact Assessment due to its funding structure, it’s claimed. The White House doesn’t directly pay AT&T - instead the ONDCP provides a grant to the Houston High Intensity Drug Trafficking Area, which is a partnership between federal, state, and local law enforcement agencies. And this partnership, in turn, pays AT&T to operate this surveillance scheme.

See also: Using Metadata to find Paul Revere.


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