What is IMSI-Catcher ?
An IMSI catcher is a cell phone surveillance device that acts as an improvised fake base station. With an IMSI catcher, law enforcement can impersonate a telecommunications company in order to track the location of a target mobile phone, monitor its calls and text messages, and intercept data traffic to gather information about the individual carrying the targeted device.
IMSI catchers are used by law enforcement agencies worldwide for tracking suspect phones and for investigating criminal activity, but their use is controversial due to privacy concerns. Law enforcement agencies do not need warrants or court orders in order to deploy IMSI catchers on-location and they are sometimes used without informing suspects of their use until after they have been captured or arrested.
The use of IMSI catchers traces back to the late 1990s. In 2008, a study by the “New York Times” revealed that US law enforcement had used IMSI catchers since at least 2006.
In 2009, both the U.S. Federal Bureau of Investigation (FBI) and the Drug Enforcement Administration (DEA) acknowledged that they had used IMSI catchers, and stated that they were no longer using them for investigations. The U.S. National Security Agency (NSA) also confirmed their use in a response to questions from Senator Ron Wyden but said they did not use it for criminal investigations or taps on American citizens.
USSOCOM, which oversees U.S. Special Operations Command (USSOCOM) forces, stated that IMSI catchers are permitted in its operational areas.
The DEA admitted using IMSI catchers for narcotics investigations of U.S. citizens and stated that they have a policy restricting their use on U.S. citizens, but they were known to have used them on non-US citizens. A report by “The New York Times” showed some American police forces, after reading about how other law enforcement agencies use IMSI catchers domestically, had conducted at least one domestic operation using an IMSI catcher in 2004 without notifying a judge of approval for the surveillance and without notifying any of the suspects whose phone numbers were intercepted.
Antennas can be hidden in a number of inconspicuous locations, including vehicles, as a mobile device or within fixed locations. They can be powered by a number of sources, including electrical outlets and solar panels. Police in Canada has considered using towers disguised as trees for IMSI catchers.
An IMSI catcher is able to “spoof” a legitimate cell tower in order to establish connections with any mobile devices that are within range and using the same frequency as the IMSI-catcher. Communication is thus possible between the IMSI catcher and the target while also communicating to other devices operating on the same frequency. This allows a significant range of targets to be monitored with great accuracy. An IMSI catcher can also interact with modems and router stations within range, allowing monitoring of data from communications systems such as email or BitTorrent traffic.
Data captured by an IMSI-catcher can be stored for later review by law enforcement agencies, and can be used in investigations on several fronts.
It has been proposed that a tax-funded network based on wireless signals could provide free internet access at speeds 100 times faster than current Wi-Fi and 4,500 times faster than 3G mobile data networks.
Radio transceivers are required to serve as repeaters or to re-transmit packets between the wireless network and a fixed-line network, in order to support mobile phone service in areas with weak reception. It is possible for operators of IMSI catchers, which are used by law enforcement agencies worldwide to track and monitor cell phones, to exploit these vulnerabilities in order to identify the individual using certain devices. This information can be used not only for identifying suspects and tracking their movements but can likewise be used for extortion purposes.
In September 2017, thousands of cellphones that were set on airplane mode were fooled into connecting with an IMSI-catcher after they passed by a beacon tower disguised as an ordinary cell phone tower.