[liberationtech] EFF's Rayhunter, and an earlier iteration

[Rick Valenzuela]

I had been meaning to post this, but did you see a couple weeks ago EFF released Rayhunter, a cool new open-source tool for detecting IMSI catchers, or cell-site simulators?[1]

Seeing this triggered my memory about SeaGlass[2], a project that security researchers at the University of Washington in Seattle did in 2017. They made sensors with Raspberry Pis and asked rideshare drivers to toss them in their trunk while they work. From the press release: "[...] around an immigration services building south of Seattle run by the U.S. Department of Homeland Security, SeaGlass detected a cell tower that transmitted on six different frequencies over the two-month period. That was notable because 96 percent of all other base cell towers broadcast on a single channel, and the other 4 percent only used two or three channels."

Anyway, this looks to be what EFF wants to do with its telemetry, and possibly reaching out to rideshare or delivery drivers could move this project along further and faster.

[1] https://www.eff.org/deeplinks/2025/03/meet-rayhunter-new-open-source-tool-eff-detect-cellular-spying

[2] https://www.washington.edu/news/2017/06/02/catching-the-imsi-catchers-seaglass-brings-transparency-to-cell-phone-surveillance/


Rick
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Rick Valenzuela
he/him/his
Miami, FL