What is SIMBOX:
A SIM box is device that maps the call from VoIP to a SIM card (in the SIM box) of the same mobile operator of the destination mobile.So that international call terminating as home call to subscriber country and usually cheap compared to the cost of terminating the international call.This is to just bypass international traffic.Commonly, SIM boxes are used to perpetrate bypass fraud, so we shall use this technique for illustration.
Normal call flow from Visitor country to home country Subscriber
In case of SIM BOX, call routing like
In this figure sim box is working as a ‘plug-in and work’ box that contains a mobile SIM card that is connected to a PBX or router. It can automatically reroute a call that would take place on a mobile network to a lower cost fixed or IP network.
Detection of fraud can be some what tricky because in some cases.
– Some SIM boxes uses IMEI management.. which changes their IMEI constantly making it dificult to detect.
– MSISDNS are also chnages regularly.
In general we detect the fraud with constantly looking various calling parameters. We further classified these parameters into Indicators. By looking indicators we can analyse frequent usage MSISDN and IMSI for RA perspective.
The Indicators are based on;
– High volume of calls from the same MSISDN’s and IMEI’s.
– High volume of calls from the same cell id (this boxes are located in an office).
– Last recource would be to call terminating customers and try to find out about the quality of the calls.
For shake we divide indicators.
Indicator 0 – flags high incoming calls from other carriers for potential simbox terminating to Aparty.
Indicator 1 – flags high outgoing calls for potential simbox operators and other form of fraud/abuse in usage
Indicator 2 – flags high sms for potential abuse in usage or virus mobile phones
Indicator 3 – use to detect high usage subscribers for potential fraud/abuse in usage
Indicator 4&5 – related imei/imsi stuffing
Find more about SimBox fraud at http://telecom4u.in/home/sim-box-fraud-2/