Wired has an unsettling bit of tech reporting on how easy it is to see nearly all of our secrets with about $800 worth of equipment. Phone calls, internet searches, Signal chats, troop positions, Zoom meetings, reading science websites… it all might be encrypted on either end, but the information streaming in and out of satellites overhead isn’t encrypted — and it’s possible to just listen in:
For three years, the UCSD and UMD researchers developed and used an off-the-shelf, $800 satellite receiver system on the roof of a university building in the La Jolla seaside neighborhood of San Diego to pick up the communications of geosynchronous satellites in the small band of space visible from their Southern California vantage point. By simply pointing their dish at different satellites and spending months interpreting the obscure—but unprotected—signals they received from them, the researchers assembled an alarming collection of private data: They obtained samples of the contents of Americans’ calls and text messages on T-Mobile’s cellular network, data from airline passengers’ in-flight Wi-Fi browsing, communications to and from critical infrastructure such as electric utilities and offshore oil and gas platforms, and even US and Mexican military and law enforcement communications that revealed the locations of personnel, equipment, and facilities.
“It just completely shocked us. There are some really critical pieces of our infrastructure relying on this satellite ecosystem, and our suspicion was that it would all be encrypted,” says Aaron Schulman, a UCSD professor who co-led the research. “And just time and time again, every time we found something new, it wasn’t.”
The group’s paper, which they’re presenting this week at an Association for Computing Machinery conference in Taiwan, is titled “Don’t Look Up”—a reference to the 2021 film of that title but also a phrase the researchers say describes the apparent cybersecurity strategy of the global satellite communications system. “They assumed that no one was ever going to check and scan all these satellites and see what was out there. That was their method of security,” Schulman says. “They just really didn’t think anyone would look up.”
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Anyone who sets up their own satellite receiver in the same broad region as one of those remote cell towers—often as far as thousands of miles away—can pick up the same signals meant for that tower. Doing so allowed the research team to obtain at least some amount of unencrypted backhaul data from the carriers T-Mobile, AT&T Mexico, and Telmex.
The T-Mobile data was particularly significant: In just nine hours of recording T-Mobile backhaul satellite communications from their single dish, the researchers collected the phone numbers of more than 2,700 users as well as all the phone calls and text messages the researchers received during that time. They could, however, only read or hear one side of those conversations: the content of the messages and calls sent to T-Mobile’s remote towers, not sent from them to the core cell network, which would have required another satellite dish near the one T-Mobile intended to receive the signal on the other end.
“When we saw all this, my first question was, did we just commit a felony? Did we just wiretap?” says Dave Levin, a University of Maryland computer science professor who co-led the study. In fact, he says, the team didn’t actively intercept any communications, only passively listened to what was being sent to their receiver dish. “These signals are just being broadcast to over 40 percent of the Earth at any point in time,” Levin says.
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You can read the team’s research here, at UC San Diego’s SatCom.