Controversial mobile phone tracking technology is being deployed as a tool in President Donald Trump's expanding effort to arrest and deport illegal US residents.
In March, US Immigrations and Customs Enforcement (ICE) deployed a mobile-site simulator, often colloquially referred to as a "Stingray", to track a Michigan man in the country illegally, according to recently unsealed court documents reported first by The Detroit News.
The local news outlet reported yesterday that a team of FBI and ICE agents in Detroit used a mobile-site simulator to locate Rudy Carcamo-Carranza, a restaurant worker from El Salvador who had twice entered the country illegally. The 23-year-old was reportedly accused of driving drunk and being involved in a hit-and-run crash.
This represents the first known case of such a device being used to hunt down an undocumented immigrant. Nathan Wessler, a staff attorney at the American Civil Liberties Union and widely recognised expert on mobile-site simulator use, told the Michigan paper that he had never before seen a warrant approved in an immigration enforcement operation.
The use of mobile-site simulators is a closely guarded secret among US law enforcement, typically bound by a nondisclosure agreement between agencies, the FBI, and the Harris Corporation, a US-based company which produces the "Hailstorm" model, an advanced version of the more widely known "Stingray".
A portable device the size of a suitcase, the Hailstorm operates by emulating base transceiver stations, or "mobile towers". By transmitting a radio signal more powerful than that of legitimate mobile towers in the vicinity, the Hailstorm forces nearby mobile phones to drop their connections to legitimate networks — those operated by AT&T, Verizon and other providers — and re-connect instead to the police device. This works by exploiting the fact that mobile phones are intentionally designed to always seek out the most powerful signal nearby in an effort to reserve battery power. The process, however, is more complex than just that.
The Harris device isn't just passively collecting information on nearby mobile phone users by pretending to be something it isn't. With regards to modern LTE networks on which most mobile phones in the US operate, a more apt description for the Hailstorm is a "mobile hacking device". Older GSM networks only require mobile phones to authenticate in one direction: The mobile phone, in other words, must prove it is authorised to be on the network, but the mobile tower does not have to respond in kind. LTE, however, uses a more secure protocol known as "two-way authentication".
What this means, essentially, is that the only way a Hailstorm can fool a mobile phone is by authenticating itself back to the device, perfectly emulating a complex, multi-step "handshake" with fraudulent credentials. (A hack by any other name is still a hack.)
The use of these devices under any circumstance poses unique risks to bystanders. Mobile-site simulators are known to disrupt calls, even ones placed to emergency services. A 2014 case in Canada noted that mobile-site simulators pose inherent risks to "innocent third parties", particularly those trying to reach emergency services. Canadian authorities instituted a three-minute rule with regards to their use after tests showed frequent malfunctions in software designed to allow emergency calls to go through. No such limitations have been imposed in the US, however.
Because coverage blackouts are a byproduct of using mobile-site simulators they have often been compared to mobile phone jammers, the use of which constitutes a federal crime in the US.
The Federal Communications Commission defines a mobile phone jammer as a device that prevents mobile phones from "making or receiving calls, text messages, and emails", and further notes that jammers do not "discriminate between desirable and undesirable communications". While that definition appears to fit the bill, and federal law prohibits police from using mobile phone jammers under any circumstance, the FBI and other federal agencies routinely provide state and local police with access to mobile-site simulator technology. Other agencies, including the US Secret Service, are known to share their devices with local agencies.
Law enforcement operations to locate, detain and deport individuals in the US illegally are skyrocketing. Figures released this week by Acting ICE Director Tom Homan show a nearly 40 per cent uptick in detentions during President Trump's first 100 days in office. As many as 41,300 undocumented immigrants have been arrested, and of those, nearly 11,000 had no prior criminal convictions — that's double the number arrested over the same period last year.
While Homeland Security requires ICE and other agencies under its umbrella to obtain warrants before deploying mobile-site simulators, should their use become typical, the result may be increased network issues for law abiding citizens. Due to the secrecy surrounding use of these devices, it will be well-nigh impossible to attribute any such disruption to ICE's enforcement operations.
In a statement to The Detroit News yesterday, an ICE spokesman Khaalid Walls defended the agency's use of mobile-site simulators: "ICE officers and special agents use a broad range of lawful investigative techniques in the apprehension of criminal suspects," he said. "Cell-site simulators are invaluable law enforcement tools that locate or identify mobile devices during active criminal investigations."