#LTEWS #Security I was at a roundtable discussion recently talking about security in the mobile carrier networks. During the discussion the recently announced SS7 signaling hack was introduced as an example. I would propose that this vulnerability is not a hack, but just poor design where trust is poorly assumed.


Before you scream that I have my head stuck in the sand and I am ignoring a real threat that exists today for all mobile users, let me explain. The ‘hack’ in question depends on an agent to pose as a carrier wanting to interconnect with another established carrier for roaming and message forwarding capabilities.

This is where the trust is involved. Interestingly, this is not as hard to do as one might think. With all the small carriers around the world and the MVNOs popping up like rabbits, it is hard to validate an entity with a 100% certainty. Once the trusted connection is established, now it is possible to send SS7 messages that can gain information that one should not normally have access to.

There have been NO cases where an agent with malicious intent has been able to establish themselves to be in a position to send and receive SS7 information without establishing a trusted connection via a wrongly trusted, but legitimate processes.

The reason I do not call this a hack, is that there is nothing technical about the method to gain access. This is purely social engineering. I can pose as a hedge fund and potentially gain some access to a larger financial company’s network infrastructure through a dedicated partner connection, but is that a ‘hack’? There are no software bugs, buffers to overflow, root access to obtain, or any other technical function that one thinks of when hacking to accomplish this compromise.

So far, there have been NO instances reported or claimed of someone consciously and maliciously hacking or gaining information via the SS7 protocol.

Now that I have THAT out of the way, let’s talk about the security in the current and future generation mobile networks, LTE. LTE uses a completely different model which uses an all-IP infrastructure and new protocols including Diameter, and protocols like SIP for new functions such as VoLTE. And we have our favorite attack vector, DNS, pervasively within the entire control plane infrastructure.

LTE has major security concerns that need to be addressed because the traditionally closed control plane network is becoming exposed to the external (and hacker) community. SIP messages can be generated from one’s smart device and forwarded directly into the IMS infrastructure. DNS is used to forward messages from service function to service function within this previously closed network. It is possible that Diameter messaging can be exposed since it is easy for a malicious agent to hide their identity so it is impossible to find the source of the compromise via a fake origin ID.

I wrote an introduction to this problem in an earlier blog post, Mobile Service Providers are missing a Key Security Issue - And it is not DNS. This is the time to take a close look at the security profile of the control plane network and determine what assurances can be put in place to prevent the malicious attacks that will certainly be forthcoming if nothing is done.