The Raleigh and Durham police departments reported last year that they use the Stingray device to investigate criminal activity, a device the FBI has held in relative secrecy since 1995. A Stingray, formally call an international mobile subscriber identity (IMSI catcher) mimics the cell phone tower’s base station through which phone data ordinarily passes in an effort to collect such data for its investigative use.
While even narrowed and individualized use of the technology could come with grave privacy concerns, a larger issue with its use is that it scrapes the data from all surrounding cell devices in the subscribing scope of the search. Its expected widespread use, therefore, carries several issues that threaten criminal procedure safeguards grounded in the public’s reasonable expectations of privacy found in the 4th Amendment and parallel state constitutional provisions.
It gets worse. One of the ways the Stingray triangulates a suspect’s phone number or location is to downgrade the service connectivity from 4G or 3G to 2G. Wired’s Kim Zetter details this process in her article found here. At the lower level, the area’s cell phone users will be forced into roaming tower vulnerability, as opposed to when at the higher levels the users remain in a fixed location of vulnerability. The unfixed vulnerability allows the device to mimic the tower’s location and scrape the data for its investigative use.
Why is that terrifying? It can actually disrupt service for surrounding customers while law enforcement operates the subscriber device. The FBI recently disclosed a warrant at the request of a defense counsel’s motion that admits as much. The admission makes it conceivable that the use of the device could imperil an innocent third party’s ability to notify emergency officials of imminent harm to person or property at the expense of law enforcement’s investigation.
The privacy concerns over the use of the Stingray device and its questionable constitutional character is almost so obvious that those countering criticism often speak of its net benefit to the public due to how it enhances law enforcement’s ability to protect the streets. Even that argument is now in jeopardy. The device can place individuals within the scope of its subscription in danger because it can disrupt service at those critical times when service could mean the difference in life and death.