In a recent report published by the Wall Street Journal, information from an anonymous source attaches the U.S. Marshall service to a spy program in use since 2007. The program employs small fixed-wing aircraft equipped with devices sometimes called "dirtboxes" after the initials of the company that manufactures them. According to the report, Cessnas carrying the device, which measures two square feet, fly over an area where the person of interest is suspected to be, and collect unique identifying information from phones in the area, which is then used to locate the subject's position within three meters, or even locate which room inside a building the subject is in.
The dirtbox, named after the initials of Digital Receiver Technology, Inc., a Boeing Company subsidiary that produces them, appears to be similar to the cell site simulator known as the Stingray, which the ACLU has stated to be in use by over 46 agencies across 18 states and Washington, D.C. This device exploits default behavior in cell phone radios in which the tower that has the strongest signal is the one that the phone communicates with. Whenever a cell phone wishes to connect to a cell tower, it broadcasts a number known as the International mobile subscriber identity (IMSI). This number is unique to each phone and is used to identify the phones on carrier networks. Dirtboxes or Stingrays, sometimes referred to as "IMSI catchers", work by broadcasting a signal that falsely appears to cell phones as the strongest signal, causing the phones to connect to the device automatically and send their IMSI, which then is recorded by the device. The plane can then fly to a different location, repeat, and effectively triangulate the position of any phone in that area within about ten feet. Sources claim that this program essentially covers the majority of US citizens, operating out of at least five airports across the country.
The information gleaned by using this program, which Justice Department officials neither confirm nor deny, is then examined for information relevant to the person under surveillance, while the rest of the information is supposedly discarded. The Justice Department will not comment on the existence of the program, stating that doing so would undermine the effectiveness of their surveillance capabilities. The ACLU states that IMSI catchers are in use by many government agencies, including the FBI, ATF, DEA, NSA, and others. The NSA has come under scrutiny recently, for its methods of collecting phone records in bulk from phone companies. Government agencies can request to have information on a suspect's phone released by phone companies, but with this technology, the carriers can simply be skipped and the data gathered directly by the government. Officials did state that all methods in use for collecting information are legal, and court orders for information are obtained in compliance with federal law. What is unclear, however, is how the scope of these searches are laid out in the requests. Since these orders are sealed, the lack of oversight for these alleged surveillance programs is a cause for concern. The technology has been known to be used overseas by both the U.S. military and intelligence officials, but news of its usage on home soil against U.S. citizens is relatively new.
As more information regarding the scope of U.S. intelligence gathering surfaces, it is likely we will be seeing much more debate surrounding the usage and regulation of new surveillance technology, as well as calls for more transparency and oversight.