GSM security testing: where the action is [LWN.net]

GSM security testing: where the action is

Posted Sep 27, 2010 8:48 UTC (Mon) by nhippi (subscriber, #34640)
In reply to: GSM security testing: where the action is by bronson
Parent article: GSM security testing: where the action is

It is already specified as IMS (IP multimedia system), and it is requirement for the "next generation" phone standard, LTE. However, I don't see how that is going to make life better security-wise that GSM voice. SIP is notoriously insecure protocol (hello please route phonecalls unencrypted to this IP, trust me because here is my password in plaintext). Also reliability and battery life is worse, so there is valid questioning in the industry on "why bother?".

GSM security testing: where the action is

Posted Sep 27, 2010 11:59 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link] (11 responses)

LTE is going to use H.323 family of standards for audio/video data. It's fiendishly complex, but pretty powerful and certainly is secure.

As for pausing bittorrents - that's what QoS is for.

GSM security testing: where the action is

Posted Sep 27, 2010 15:50 UTC (Mon) by i3839 (guest, #31386) [Link]

"fiendishly complex" and "secure" are mutually exclusive.

I hope the security part is simple and separate from the complex rest.

GSM security testing: where the action is

Posted Sep 27, 2010 22:10 UTC (Mon) by marcH (subscriber, #57642) [Link] (5 responses)

Scalability issues aside, IP QoS usually falls into a chicken and egg problem where each potential IP bottleneck postpones implementation of QoS until other bottlenecks do it first.

Yes designing a brand new network is a nice opportunity but... seeing is believing.

GSM security testing: where the action is

Posted Sep 28, 2010 11:40 UTC (Tue) by Cyberax (✭ supporter ✭, #52523) [Link] (4 responses)

QoS on cell phone providers' networks is not hard to do. They'll probably just do it per-protocol.

On the wide Internet it's probably not going to make much difference, anyway. Voice traffic is fairly narrow-band, even high-quality codecs do not require more than 64Kbit.

GSM security testing: where the action is

Posted Sep 28, 2010 15:44 UTC (Tue) by marcH (subscriber, #57642) [Link]

> On the wide Internet it's probably not going to make much difference, anyway. Voice traffic is fairly narrow-band, even high-quality codecs do not require more than 64Kbit.

Narrow band does not grant immunity from occasional packet loss and high latencies. Only QoS helps in such cases.

GSM security testing: where the action is

Posted Sep 30, 2010 7:18 UTC (Thu) by Cato (guest, #7643) [Link] (2 responses)

Talking to a local expert in mobile technology, I get a lot of scepticism about QoS for mobile - although it's enabled in the 3GPP UMTS standards, nobody seems to have enabled this. The radio link is critical and very variable - however it may be that IP QoS gets turned on for the mobile backhaul link from base station up to the core network, as this is turning into something of a bottleneck. Making QoS work does require quite a big investment in policy server infrastructure, adapting your use of network planning tools, and so on, but this is probably paid back if you are using it to stop very large downloaders and ensure that VoIP and video are usable.

GSM security testing: where the action is

Posted Sep 30, 2010 13:03 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link] (1 responses)

Yeah, nobody uses QoS. It's not needed for data services (cell phone providers do not care if your Skype works badly if Youtube video is playing on your phone) and voice traffic goes over links with guaranteed bandwidth.

Quite often voice and data backbones also use separate circuits, so QoS is not used even there.

GSM security testing: where the action is

Posted Oct 6, 2010 9:39 UTC (Wed) by marcH (subscriber, #57642) [Link]

> and voice traffic goes over links with guaranteed bandwidth. Quite often voice and data backbones also use separate circuits, so QoS is not used even there.

This is actually some simple, manual, very coarse form of QoS when you think about it. Simple => works.

GSM security testing: where the action is

Posted Sep 29, 2010 8:43 UTC (Wed) by mfedyk (guest, #55303) [Link] (1 responses)

both sip and h.323 use rtp as their media transport for audio/video. can you be more specific as to what in lte is similar to h.323?

GSM security testing: where the action is

Posted Sep 29, 2010 9:04 UTC (Wed) by Cyberax (✭ supporter ✭, #52523) [Link]

LTE is (currently) going to use H.323 for signaling on end-user devices. Which is kinda logical, because H.323 is most widely used in telecoms.

GSM security testing: where the action is

Posted Sep 29, 2010 19:25 UTC (Wed) by nhippi (subscriber, #34640) [Link] (1 responses)

LTE is going to use H.323 family of standards for audio/video data

Can you provide some reference for this claim? Every source I know refers LTE being based on IP Multimedia System, Where SIP is the protocol to handle voice (and video) calls.

GSM security testing: where the action is

Posted Sep 30, 2010 19:10 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

Ah. You're right, I asked a person who is directly involved in development of LTE standards.

H.323 is not going to be used on end-user devices. Which is a saner decision then what I expected from committees. It was still on the table last time I inquired about it, so I'm sorry for misinformation.

GSM security testing: where the action is

Posted Sep 27, 2010 13:15 UTC (Mon) by tzafrir (subscriber, #11501) [Link] (2 responses)

Plain text password in SIP?

GSM security testing: where the action is

Posted Oct 2, 2010 16:36 UTC (Sat) by job (guest, #670) [Link] (1 responses)

I guess it's allowed by the standards but I've never seen it in practice.

There's a lot of guesswork going on in this discussion thread.

GSM security testing: where the action is

Posted Oct 7, 2010 9:08 UTC (Thu) by marcH (subscriber, #57642) [Link]

Not very surprising considering how obscure is this industry.