You’ve probably seen it many times on TV a shifty-eyed individual, roams the city, up to no good, enroute to committing some violent or criminal act. The good guys know he/she is out there, but have no idea where. “It’s like finding a needle in a haystack” someone grimly comments. The suspenseful music rises as they pursue frantically and then…
Televised drama aside, this scenario is a quite realistic one. Cell phones provide universal connectivity and immediate access to the vast amounts of information on the web. They have been credited with empowering individuals such as doctors, police officers and even farmers in the field by acting as a force multiplier, arming them with the data and real-time analysis they need to be effective. Unfortunately, this also applies to individuals with nefarious intentions, allowing them to to remain anonymous while simultaneously conspiring with others. Since they no longer need to physically meet face to face, they severely limit the opportunities law enforcement has to catch them together and positively identify the threat.
Enter the IMSI-catcher. This device allows its operator to establish a virtual cell tower, ‘fooling’ every mobile phone within range into diverting their communications through a proxy. The phone ‘thinks’ it is communicating with the mobile network, when in fact it’s immediately connected to the catcher, which then passes on the connection to the nearest legitimate tower .
Once the target’s international mobile subscriber identity (IMSI) is known, authorities can track it, thereby locking a very bright light onto the needle’s whereabouts. And even though the more advanced mobile network protocols allow for stronger encryption, once a phone connects to the IMSI-catcher it can be manipulated to downgrade to an older, less secure network, laying bare the contents of the communication. The cloak of invisibility and anonymity is now lifted.
So it is no wonder why official approval to purchase and operate IMSI-catchers is limited only to law-enforcement agencies.
