I refuse to have a cell phone because they are tracking and
surveillance devices. They all enable the phone system to
record where the user goes, and many (perhaps all) can be
remotely converted into listening devices.
I don't know if that's what he meant by 'listening devices'. In any way, a lot of these statements make a lot of sense for many citizens in different parts of the world (China etc), where there's a corrupt government and a suppressed freedom of speech. For an US citizen I suppose they may be exaggerated. But I share many of his views, and he obviously deserves a lot more respect than some people show towards him.
EDIT. And of course, if it's running non-free software the cell phone can easily be made to transmit microphone data without the user noticing.
Most phones can be remotely updated with software by the carrier, and the GSM protocol allows for remote update of the firmware.
Through I suspect there are much easier methods, such as attacking the software stack itself like: https://www.usenix.org/system/files/conference/woot12/woot12...
As an aside, when I was porting Linux to the Motorola Q I realized I could easily turn off the display and key backlight and turn on the microphone and camera though the sysfs,this would appear to anyone as if the phone was off but I could remotely control it (SSH tunnel) and capture audio and video. The only problem would be the heat, but someone would likely assume it was used for a while before powering it off. This without any low-level firmware change, just booting GNU/linux ;) from HaRET.
I think a clever surveillance agency with inside access to the guts of the phone could make it very, very hard to detect.
The question is can they do it to everyone frequently, including the handful of super-nerds out there who love tracing every operation their devices do and can be certain they don't have some sort of malware? While I don't see the capability as technologically infeasible, I do think it would be noticed sooner or later if it was always-on.
If such a feature does exist, then it would have to be used sparingly on targeted individuals, and even then if it was used to incriminate them such evidence would have to come up in court (unless they all get the s/Gitmo/secret prison/ treatment, a big assumption!) and then the world would know such features exist. Presently I think traditional manners of evidence-gathering are probably sufficient and people publicly leak all sorts of data (or have a lot of data logged that can be subpena'd) -- plus every now and again we hear about some nerd (https://news.ycombinator.com/item?id=5194489) reporting they have been bugged. Some people think the CPUs of Intel et al. have backdoors in them, but if so, there'd be no need to bug computers.
Absence of evidence is evidence of absence... so I don't really take the government backdoors in everything by default too seriously. I'd need some sort of evidence showing their existence to change my mind.
Here you go, seems pretty well sourced: http://en.wikipedia.org/wiki/Covert_listening_device#Remotel...
The problem boils down to this: baseband (the chip doing the GSM, LTE, .. communication) processors are completely propietary. There is no source for the software running on them, it's a big binary blob. And the other big problem is that baseband processors have become a hub for any analog processing. They run the GPS chip and they are the DSP for the microphones. Combine access to all vital systems and the primary communication link, and business practices in the big, sometimes partially government owned, companies producing the software for these chips.. it makes for an explosive mixture in a "mobile first" world.
Recommended talks: http://vimeo.com/25806106 http://www.youtube.com/watch?v=e1lYU0VMCoY
Nowadays if FedGov wanted to do it, it would implant malware.