Most GEO Satellites Broadcast Unencrypted Data — A Cheap Dish Lets Anyone Eavesdrop

Researchers Find Large-Scale Satellite Privacy Gap

Researchers at UC San Diego and the University of Maryland have discovered that many geostationary (GEO) satellites transmit civilian, commercial, financial and even some military communications in plain text. Using an off-the-shelf, unmodified satellite dish that cost a few hundred dollars, the team intercepted sensitive traffic including VOIP and cellular audio, telemetry tied to critical infrastructure, military surveillance feeds and signals related to ATM networks.

Why it matters: GEO satellites sit far from Earth but broadcast over very large footprints — roughly 40% of the planet from a single satellite — so a modest receiver can passively capture traffic over huge regions. The researchers originally planned to test whether they could break satellite encryption, but in many cases they never needed to: the links were not encrypted at all.

The problem largely stems from older GEO systems that were not designed with modern transport security as a default. The situation is similar to the early web before HTTPS and TLS became standard: many satellite links were simply never updated to use encrypted transport protocols.

Recommended fixes and current response

The researchers recommend adopting standard transport-layer protections — for example, TLS — on satellite links. Low‑Earth‑orbit (LEO) operators such as SpaceX's Starlink already use TLS by default. Since the study was published, several organizations (including T‑Mobile, Walmart and KPU) have reported they encrypted affected systems; the research team believes these were likely software updates rather than hardware replacements.

Risks and outlook: There are no widely reported catastrophic incidents linked publicly to these cleartext broadcasts so far, but the researchers warn the exposure could have been—and might be—exploited by intelligence services or cybercriminals. They expect interest in space‑based data collection and related cybercrime to rise as awareness grows.

Practical mitigations

Short-term: enable transport encryption (TLS), update satellite ground-station software, rotate and protect keys, and apply network-level safeguards. Long-term: build secure-by-default satellite communication standards and require encryption in procurement contracts.

The discovery highlights a simple but urgent message: encrypt satellite links and make secure defaults the norm before malicious actors scale exploitation.