Cell-Signal Spyware Uncovered At Democratic National Convention

The 2024 Democratic National Convention (DNC) in Chicago was marred by concerns over potential surveillance, with a device capable of intercepting phone signals likely deployed. The Electronic Frontier Foundation (EFF), a digital rights advocacy organization, has identified the device as a cell-site simulator, which mimics cell towers to collect sensitive data such as call metadata and location information from all phones within its range.

The EFF’s investigation into wireless signal data collected by WIRED during the event revealed that the device was likely deployed. The organization has been monitoring wireless signals at protests and event locations across Chicago, collecting extensive data during the political convention.

A breakthrough came when EFF technologists applied a new heuristic to examine situations where cell towers requested IMSI (international mobile subscriber identity) numbers from devices. On August 18—the day before the convention officially began—a device carried by WIRED reporters en route a hotel housing Democratic delegates from states in the US Midwest abruptly switched to a new tower. That tower asked for the device’s IMSI and then immediately disconnected—a sequence consistent with the operation of a cell-site simulator.

“This is extremely suspicious behavior that normal towers do not exhibit,” says Cooper Quintin, a senior technologist at the EFF. The deployment of cell-site simulators raises critical questions about national security and individual privacy. In the US, law enforcement agencies are required to obtain a warrant to deploy such devices under Illinois law. However, a 2023 DHS Inspector General report found that both the Secret Service and Homeland Security Investigations did not always comply with these requirements.

The EFF’s discovery has sparked widespread criticism from privacy advocates and activists, who argue that such technology can be exploited to covertly monitor protestors and suppress dissent. During the DNC, thousands of demonstrators faced a heavy law enforcement presence, including officers from the US Capitol Police, Secret Service, Homeland Security Investigations, local sheriff’s offices, and Chicago police.

As the investigation into cell-site simulator deployment continues, it remains unclear who was responsible for its use and why. However, one thing is certain: the potential risks to individual privacy and national security have been raised, prompting a renewed call for greater transparency and oversight of surveillance technologies.