28C3: New attacks on GSM mobiles and security measures shown (The H) [LWN.net]

28C3: New attacks on GSM mobiles and security measures shown (The H)

Posted Dec 30, 2011 21:43 UTC (Fri) by josh (subscriber, #17465)
In reply to: 28C3: New attacks on GSM mobiles and security measures shown (The H) by Cyberax
Parent article: 28C3: New attacks on GSM mobiles and security measures shown (The H)

If GSM radios fail to work just because one device doesn't play nice, the network has fundamental flaws to begin with. Nothing short of broadband noise (active jamming) should prevent a properly designed radio protocol from operating, and it seems simple enough for regulations to say "don't spew noise". Anything more than that just compensates for vulnerabilities in a badly designed protocol.

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28C3: New attacks on GSM mobiles and security measures shown (The H)

Posted Dec 31, 2011 11:06 UTC (Sat) by Cyberax (✭ supporter ✭, #52523) [Link]

Duh. GSM has quite a lot of fundamental flaws.

Designing a radio network resilient against malicious interference is definitely not easy. Especially if it's a TDMA network like GSM. Your signal can be quite easily suppressed by a phone which is closer to a base station, it's pure physics and there's nothing you really can do about it.

CDMA networks are more resilient by design (since they use spread-spectrum encoding).

28C3: New attacks on GSM mobiles and security measures shown (The H)

Posted Jan 5, 2012 14:44 UTC (Thu) by yaap (subscriber, #71398) [Link]

I generally agree and support all what you say. Only exception is on the last point:

> CDMA networks are more resilient by design (since they use spread-spectrum encoding).

Actually CDMA network are extremely sensitive to power control, much more than GSM for example. A device transmitting too loud can badly degrade the capacity of a cell.

As you say, it's all physics in the end, and very hard engineering. All communication systems, whether 2G, 3G of 4G (either LTE or WiMAX), in order to maximize the system capacity and make it workable need to have properly behaving devices. Devices that do proper time, frequency and power control for sure, these are the key point to make sure a device will not degrade other devices experience.

To support your point: ensuring this is tricky, and that's why many countries (at least in Europe) requires a device to have passed a suitable certification program to be used on mobile communication bands. Look for "GCF" as the key example for 3GPP standards. Using a non-certified device is simply illegal.