IMSI catchers, also known as stingrays, are fake cell phone towers that intercept your traffic and spy on you. + Each generation of cell phone protocols has attempted to mitigate stingrays, but each has generally failed. + With 5G, more of the traffic is encrypted in such a way that it prevents stingray spying. + However, 5G networks can run in a blended 4G/5G mode, where the control channel is 4G and the data channel is 5G. + This is known as 5G NR NSA (5G New Radio Non-Standalone) mode. + When connected to such a blended network, a cell phone is not protected against + modern stingray attacks.
+ +The Android status bar does not differentiate between 5G modes. It will display the same 5G icon for Standalone and Non-Standalone networks. + The purpose of Privacy Cell is to make it easy to tell what type of network you are connected to. + If you are in an area where you usually are connected to a 5G NR SA network and Privacy Cell shows a 5G NR NSA connection, + it is possible that a stingray has performed a downgrade attack to spy on your communications.
+ +It should be noted that paltry attempts have been made to secure cell phone protocols in the past, which have never been sufficiently well designed to provide real protection. + Even if you are connected to a 5G NR SA network, it is likely that there are still unknown weaknesses in the network that can be exploited by a sufficiently funded adversary. + Privacy Cell will be updated regarding these types of vulnerabilities as future research identifies them.
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