The Department of Homeland Security s Response to Senator Ron Wyden s November 17 2017 Letter 1 Has DHS seen any evidence of foreign IMSI catchers operated in the National Capital Region a If yes was this evidence reported to any congressional committees The Department of Homeland Security s DHS National Protection and Programs Directorate NPPD has observed anomalous activity in the National Capital Region NCR that appears to be consistent with International Mobile Subscriber Identity IMSI catchers NPPD has not validated or attributed such activity to speci c entities or devices This information was reported to our Federal partners at the time it was observed 2 Does DHS agree that foreign government use of IMSI catchers in the National Capital Region poses a threat to US national and economic security Information regarding the sources and methods that foreign governments use to conduct intelligence activities is generally classi ed NPPD believes the use of these devices by malicious actors to track and monitor cellular users would be unlawful and threaten the security of communications resulting in safety economic and privacy risks NPPD agrees that the use of IMSI catchers by foreign governments may threaten US national and economic security 3 Does DHS currently have the technical capability to detect foreign IMSI catchers in the National Capital Region a If yes has DHS deployed assets capable of detecting foreign IMSI catchers in the National Capital Region b If no what would DHS need to have this technical capability NPPD is not aware of any current DHS technical capability to detect IMSI catchers To support such a capability DHS would require funding to procure deploy operate and maintain the capability which includes the costs of hardware software and labor 4 Has DHS seen evidence of foreign IMSI catchers in other major US cities and does DHS agree that foreign IMSI catchers in other cities would pose a serious threat to US national and economic security a If DHS has seen evidence of foreign IMSI catchers in other major US cities what steps has DHS taken to respond NPPD is aware of anomalous activity outside the NCR that appears to be consistent with IMSI catchers NPPD has not validated or attributed this activity to speci c entities or devices However NPPD has shared this information with Federal partners 5 Native 4th Generation IMSI catchers are now openly advertised by surveillance technology companies Does DHS currently have the technical capability to detect IMSI catchers March 2018 Page 1 a If not what resources if any has DHS invested to address this advanced surveillance threat NPPD is not aware of any current DHS technical capability to detect IMSI catchers To support such a capability DHS would require funding to procure deploy operate and maintain the capability which includes the costs of hardware software and labor March 2018 Page 2 This document is from the holdings of The National Security Archive Suite 701 Gelman Library The George Washington University 2130 H Street NW Washington D C 20037 Phone 202 994-7000 Fax 202 994-7005 nsarchiv@gwu edu