Mobiles vulnerable to base station exploits

Trojan

Interesting, I wonder how plausible it is to actually set this up? Reminds me of the phone network thing from Batman...

Every smartphone or other device with mobile communications capability (e.g. 3G or LTE) actually runs not one, but two operating systems. Aside from the operating system that we as end-users see (Android, iOS, PalmOS), it also runs a small operating system that manages everything related to radio. Since this functionality is highly timing-dependent, a real-time operating system is required.

This operating system is stored in firmware, and runs on the baseband processor. As far as I know, this baseband RTOS is always entirely proprietary. For instance, the RTOS inside Qualcomm baseband processors (in this specific case, the MSM6280) is called AMSS, built upon their own proprietary REX kernel, and is made up of 69 concurrent tasks, handling everything from USB to GPS. It runs on an ARMv5 processor.

The problem here is clear: these baseband processors and the proprietary, closed software they run are poorly understood, as there's no proper peer review. This is actually kind of weird, considering just how important these little bits of software are to the functioning of a modern communication device. You may think these baseband RTOS' are safe and secure, but that's not exactly the case.

[..]

While we can sort-of assume that the base stations in cell towers operated by large carriers are "safe", the fact of the matter is that base stations are becoming a lot cheaper, and are being sold on eBay - and there are even open source base station software packages. Such base stations can be used to target phones. Put a compromised base station in a crowded area - or even a financial district or some other sensitive area - and you can remotely turn on microphones, cameras, place rootkits, place calls/send SMS messages to expensive numbers, and so on. Yes, you can even brick phones permanently.

This is such low-level, complex software that I would guess very few people in the world actually understand everything that's going on here.

That complexity is exactly one of the reasons why it's not easy to write your own baseband implementation. The list of standards that describe just GSM is unimaginably long - and that's only GSM. Now you need to add UMTS, HSDPA, and so on, and so forth. And, of course, everything is covered by a ridiculously complex set of patents. To top it all off, communication authorities require baseband software to be certified.

Add all this up, and it's easy to see why every cellphone manufacturer just opts for an off-the-shelf baseband processor and associated software. This does mean that each and every feature and smartphone has a piece of software that always runs (when the device is on), but that is essentially a black box.

Source: http://www.osnews.com/story/27416/The_second_operating_system_hiding_in_every_mobile_phone

davej

All your baseband are belong to us..

https://www.youtube.com/watch?v=fQqv0v14KKY

davej