An Android app called SnoopSnitch has the ability to detect fake cell phone towers. Called Stingrays or IMSI catchers, these tools are widely used by the FBI, NSA and various law enforcement agencies for surveillance purposes. Developed by German security researchers Alex Senier, Karsten Nohl and Tobias Engel from SRLabs, SnoopSnitch is a boon for privacy-conscious individuals.
Stingrays are devices that can locate target cell phones with great accuracy, but they work by using a “dragnet”, collecting information not just from the target but all other wireless devices in the area. These devices can also be configured to capture voice and data communications. They have been used by the federal government, as well as various state and local governments since 1995.
There is much secrecy surrounding these tools, and the government has been thought to provide misleading information about them, including “making material omissions to judicial officers when it seeks purported court authorization to use this device…such as referring to it as a pen register device…” As a result, very few criminal defense lawyers are aware of these tools and their impact on privacy and human rights.
SnoopSnitch works by capturing and examining mobile radio data to advise you on your mobile network security and can warn you about location tracking, corrupt OTA updates and the aforementioned Stingrays. The app uses a GSM Security Map available from GSM Map and the app displays its own data onto the map, looking for and displaying suspicious radio signals.
SnoopSnitch is currently only available for Android phones with a Qualcomm chipset and stock Android, or a custom ROM with a Qualcomm DIAG driver. The app also requires root privileges in order to collect mobile data.
It’s important to note that the app can’t prevent your phone from being forcibly connected to these fake base stations; it can only detect if there are any in the area and alert you.