Someone told me a few years back that most of the cellphone Baseband Processors that communicates to the towers had a backdoor in it, iirc that is how that isreali spyware worked, he was friends with the people who developed it and showed how they could access any phones data with just a phone number.
Basically a radio chip for phones that has its own code running on it which is closed source so you do not know what is going on in there.
Wiki Baseband Processor
Since the software which runs on baseband processors is usually proprietary, it is impossible to perform an independent code audit. By reverse engineering some of the baseband chips, researchers have found security vulnerabilities that could be used to access and modify data on the phone remotely.[3][4] In March 2014, makers of the free Android derivative Replicant announced they had found a backdoor in the baseband software of Samsung Galaxy phones that allows remote access to the user data stored on the phone
Someone told me a few years back that most of the cellphone Baseband Processors that communicates to the towers had a backdoor in it, iirc that is how that isreali spyware worked, he was friends with the people who developed it and showed how they could access any phones data with just a phone number.
Basically a radio chip for phones that has its own code running on it which is closed source so you do not know what is going on in there. Wiki Baseband Processor