Pierluigi Paganini
October 15, 2025
A group of researchers from UC San Diego and the University of Maryland found nearly half of geostationary satellites transmit unencrypted data, exposing sensitive consumer, corporate, and military communications to interception.
The researchers used an $800 satellite receiver for three years, uncovering vast amounts of unencrypted data, including private calls, texts, and in-flight Wi-Fi traffic, being transmitted to and from space.
“Satellites beam data down to the Earth all around us, all the time. So you might expect that those space-based radio communications would be encrypted to prevent any snoop with a satellite dish from accessing the torrent of secret information constantly raining from the sky. You would, to a surprising and troubling degree, be wrong.” reported Wired. “Roughly half of geostationary satellite signals, many carrying sensitive consumer, corporate, and government communications, have been left entirely vulnerable to eavesdropping, a team of researchers at UC San Diego and the University of Maryland revealed today in a study that will likely resonate across the cybersecurity industry, telecom firms, and inside military and intelligence agencies worldwide.”
The experts intercepted unencrypted data from geosynchronous satellites, capturing T-Mobile calls and texts, in-flight Wi-Fi traffic, critical infrastructure communications, and even U.S. and Mexican military data.
The research team pointed out that they didn’t actively intercept any communications, only passively listened to what was being transmitted by the satellites to their receiver dish.
“When we saw all this, my first question was, did we just commit a felony? Did we just wiretap?” said Dave Levin, a University of Maryland computer science professor who co-led the study. “These signals are just being broadcast to over 40 percent of the Earth at any point in time,” Levin says.
Researchers shared their findings with companies and agencies, some of them promptly addressed the issue while others have yet to fix the issue. Firms like T-Mobile quickly added encryption, but some U.S. critical infrastructure operators have not yet secured their systems. The findings reveal an unprecedented scale of satellite surveillance risks.
“We pointed a commercial-off-the-shelf satellite dish at the sky and carried out the most comprehensive public study to date of geostationary satellite communication. A shockingly large amount of sensitive traffic is being broadcast unencrypted, including critical infrastructure, internal corporate and government communications, private citizens’ voice calls and SMS, and consumer Internet traffic from in-flight wifi and mobile networks.” the researchers explained. “This data can be passively observed by anyone with a few hundred dollars of consumer-grade hardware. There are thousands of geostationary satellite transponders globally, and data from a single transponder may be visible from an area as large as 40% of the surface of the earth.”
Researchers discovered that telecoms’ use of unencrypted satellite backhaul links exposed private data from remote cell towers. Using a single $800 dish, they intercepted signals from T-Mobile, AT&T Mexico, and Telmex. In just nine hours, they captured over 2,700 phone numbers along with one side of calls and text messages from T-Mobile users, showing how easily attackers thousands of miles away could eavesdrop on sensitive cellular traffic.
Researchers discovered that Telmex was sending unencrypted voice calls and AT&T Mexico transmitting raw satellite data, including user internet traffic and metadata. They also discovered decryption keys that could have exposed additional sensitive AT&T Mexico network information, though they did not attempt to use them.
The researchers published the details on the study in the paper Don’t look up: There are sensitive internal links in the clear on GEO satellites.
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