DeepSec 2010: All your baseband are belong to us by Ralf Philipp Weinmann

I really see this working remotely, as long as you have control over a cell phone tower or you use a phony portable base station, both of which are within the NSA's reach. The thing is phone baseband software (which is reused on different phone models and controls the phone's I/O including GSM, USB, etc.) has hardly ever been under attack. When the iPhone arrived with its new security model, baseband bugs became one of the major ways to jailbreak a phone. Those bugs have been fixed one by one, but they were mostly on the USB side - the GSM side has been impractical to attack. A carefully crafted GSM packet could in 2008 and probably could now cause a buffer overflow in the baseband and gain access. An interesting presentation on the topic: [this video]

Only open-source apps on open-source operating systems [..] ...running on Open Source hardware. Many modern smartphones employ a baseband processor and an application processor with shared memory. While the app processor might be running an open-source compiled Android, the baseband processor is usually on a closed, not externally verified (and very buggy) RTOS provided by the manufacturer (Qualcomm, MediaTek, TI, ...)[0]. Owning the baseband is sufficient to gain access to the raw RAM of the application processor, to read any IM messages and keys, to manipulate data, code and whatever else you like. And all this is completely undetectable by any "antivirus" software running on the app processor. [0] [this video]