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Sunday, August 3, 2014

Cell Phone Tapping: How It Is Done and Will Anybody Protect Subscribers

You probably have read on various news websites about surveillance programs led by security services in different countries that reach phone and Internet communications of ordinary citizens. We have already wrote about possible threats to mobile telecommunication networks and today we want to put more emphasis on one of the attack vectors against mobile subscribers.

In short, the outline is like this. The attacker penetrates into the SS7 (Signaling System's No. 7) network and sends a Send Routing Info For SM (SRI4SM) service message to the network channel, specifying the phone number of an attacked subscriber A as a parameter. The subscriber's A home network sends the following technical information as a response: IMSI (International Mobile Subscriber Identity) and address of the MSC currently providing services to the subscriber.