Talk Dr Josiane KOUAM

Abstract:

Cellular SIMBox fraud bypasses international mobile calls and routes them through the internet as local mobile calls in the destination country, using VoIP GSM gateways equipped with multiple SIM cards, also known as "SIMBox." This fraud causes annual financial losses of up to $3.11 billion, national security threats, and phone conversation privacy breaches. Current approaches to mitigate SIMBox fraud present open issues that affect their effectiveness. They lack robustness against the constant refinement of fraudsters’ strategies or involve a certain implementation complexity that hinders their widespread deployment in operator networks.

This paper presents SigN , a new mitigation approach based on cellular signaling data analysis. SigN is the first-of-theliterature real-time SIMBox prevention methodology that is beyond fraudster-reach and largely deployable. SigN focuses on the cellular signaling of user devices during the network attachment, aiming to block fraudulent SIMBox devices before they can connect to the network. Through extensive indoor and outdoor experimentation, we empirically show that fraudulent SIMBox devices cause significant latency than legitimate devices during the network attachment. Especially in the authentication phase, fraudulent SIMBox devices’ minimum latency is 23°ø higher than their legitimate counterparts.We analyze such latency overhead, showing it is fundamentally shaped by factors beyond fraudsters’ control, i.e., LTE standards for authentication and Internet-based communication related protocols and vagaries. Therefore, we propose a SIMBox fraud prevention approach that adapts the standardized authentication procedure at the cellular edge, at no cost for mobile operators.