A device that can intercept telephone signals was probably deployed in Chicago during the 2024 Democratic National Convention (DNC), and learned and asked critical questions about who authorized its use and for what purpose.
The device, known as a cell website simulator, was identified by the Electronic Frontier Foundation (EFF), an organization for digital rights advocacy, after analyzing wireless signal data collected by Wired during the August event.
Simulators for Selle Site mimic cell towers to intercept communication, collect indiscriminately that collects sensitive data such as call metadata, location information and app traffic from all phones within their range. Its use has rendered widespread criticism of privacy lawyers and activists, arguing that such technology can be exploited to monitor protesters secrets and suppress otherness.
The DNC convened amid widespread protests over Israel’s assault on Gaza. While a credible influencer attended exclusive yacht parties and VIP events, thousands of protesters had a heavy presence in law enforcement, including US Capitol police officers, the secret service, homeland investigations, local sheriff and police in Chicago .
Concerns about possible supervision have led Wired to conduct a first-of-his-kind wireless recording to investigate whether cell-simulators are being used. Reporters, equipped with two rooted Android phones and Wi-Fi-Hot spots that use tracking software, Rayhunter used-an instrument developed by the EFF to detect data defects associated with these devices. Wired reporters monitored signals during protests and opportunities in Chicago and collected extensive data during the political convention.
Initial tests performed during the DNC showed no conclusive evidence of the cell website simulator activity. Months later, EFF technologists rezanalized the raw data using improved tracking methods. According to Cooper Quintin, a senior technologist at the EFF, the Rayhunter instrument stores all interactions between devices and cell towers, enabling deeper analysis as detection techniques develop.
A breakthrough came when EFF technologists applied a new heuristics to investigate situations where select towers (International Mobile Signal identity) requested. According to the EFF’s analysis, a device carried by wired reporters, on August 18 – the day before the officially started – a device that was by a hotel -democratic delegates from states in the US Middle West, suddenly to a new tower switched. That tower asked the IMSI of the device and then immediately disconnected-an order that matched the operation of a cell website simulator.
“It is extremely suspicious behavior that does not show normal towers,” says Quintin. He notes that the EFF typically observed similar patterns during simulated and controlled attacks. ‘This is not 100 percent irreversible truth, but it is a strong proof that indicates that a simulator of the cell has been deployed on the site. We do not know who was responsible – it could have been the US government, foreign actors or another entity. “
In terms of the Illinois Act, law enforcement agencies must receive a warrant to deploy cell-simulators. Similarly, federal agents – including those of the Department of Home Security – are needed to obtain warrants unless there is an immediate threat to national security. However, in a 2023 DHS inspector report, it was found that both the Secret Service and Homeland Security examinations do not always meet these requirements.