Cybersecurity Policy Report, Bicameral Legislation Would Restrict Use of Cell-Site Simulators, (Jul 31, 2025)
Legislation that would require authorities to obtain probable-cause warrants before using cell-site simulators has been introduced in the House and Senate.
The Cell Site Simulator Warrant Act “creates clear legal standards for government agencies using stingray devices by requiring warrants and establishing penalties for unlawful surveillance,” according to a news release from Sen. Ron Wyden (D., Ore.), sponsor of the Senate version of the bill.
Cell-site simulators—also known as IMSI (international mobile subscriber identity) catchers or Stingrays—are used by police, intelligence operatives, and others to track cellphones in a given area by creating a fake cell-site that nearby phones connect to.
The bill would ban the use of cell-site simulators unless a probable cause warrant is obtained from a judge. It would allow emergency use of the devices if authorities later obtained a warrant.
It would also, among other things, require data collected from bystanders’ devices to be minimized and would allow a private right of action by cellphone users who were illegally surveilled.
Sen. Steve Daines (R., Mont.) is co-sponsoring the Senate version of the bill (S.B. 2522, 119th Cong. (2025)). The House version (H.R. 4811, 119th Cong. (2025)) was introduced by Reps. Ted Lieu (D., Calif.) and Tom McClintock (R., Calif.).
All four lawmakers offered similar legislation in 2021 that failed to advance in the House or Senate (CPR, June 21, 2021).
“Law enforcement agencies need clear and transparent rules about when it’s acceptable to use stingray phone surveillance, so they can properly investigate crimes without endangering Americans' privacy or violating their constitutional rights,” Sen. Wyden said. “Our bipartisan bill protects Americans against warrantless stingray surveillance while setting clear rules for law enforcement about when and how they can use these devices.”
“The last thing Montanans want is big government surveillance, including from the use of cell site simulators,” Sen. Daines said. “Montana already has commonsense warrant requirements for stingray use, and I’m glad to join with my colleagues on this bipartisan bill to make Montana’s requirements the law of the land.”
“Cell site simulators (CSS) mimic cell towers and can be used by law enforcement to locate phones and collect large swaths of sensitive data from the public,” Rep. Lieu said. “I’m reintroducing this bipartisan legislation with my colleagues to set clear warrant requirements for using CSS and uphold the civil liberties of all Americans.”
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