During the 2024 Democratic National Convention (DNC) held in Chicago, concerns emerged regarding the possible deployment of a cell-site simulator, a technology that can intercept sensitive phone data within its vicinity. This information came to light through an analysis conducted by the Electronic Frontier Foundation (EFF) based on wireless signal data collected during the event.
Cell-site simulators mimic legitimate cell towers and are capable of indiscriminately gathering call metadata, location data, and app traffic from all mobile devices in range. Their use has generated significant criticism among privacy advocates due to the potential for covert surveillance of protestors and dissenters.
The DNC attracted considerable public attention, coinciding with substantial protests against Israel’s aggressive actions in Gaza. While VIPs and credentialed influencers enjoyed lavish parties, a substantial police presence, including personnel from the US Capitol Police, Secret Service, and local law enforcement, was deployed to manage the demonstrations.
To investigate the potential use of surveillance technologies at the DNC, WIRED conducted a wireless survey using specially equipped Android devices and detection software known as Rayhunter, developed by the EFF. Reporters monitored various locations throughout Chicago, particularly during protest activities. Initial investigations yielded no definitive evidence of cell-site simulator activity. However, a subsequent analysis of the data conducted by EFF technologists several months later suggested possible suspicious behavior consistent with a simulator’s operation.
On August 18, the day before the convention began, data indicated that a device carried by WIRED reporters switched to a different tower that requested the device’s IMSI (International Mobile Subscriber Identity) number before disconnecting—a pattern generally atypical for standard towers. Although this evidence is not conclusively definitive, it raises concerns about potential unauthorized surveillance.
Under Illinois law, law enforcement agencies are required to obtain a warrant to deploy such technologies. A report from the Department of Homeland Security’s Inspector General indicated that the Secret Service and other DHS agencies have previously failed to comply with this requirement.
In response to inquiries, the Chicago Police Department denied the deployment of cell-site simulators during the DNC, while the Secret Service refrained from discussing operational methods used during "National Special Security Events."
Privacy advocates have expressed serious alarm over the implications of such surveillance. Nate Wessler from the ACLU emphasized the chilling effect that the uncertainty surrounding these technologies can have on civil liberties and the fundamental right to protest.
