SIMBOX fraud detection and Billing

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


13 thoughts on “SIMBOX fraud detection and Billing

  1. Hello,great article i found on google. It helps me lot to understand fraud concepts towards completion of my project.I have a question ,lets say if operators detects simbox fraud happens by other operator side,then in this scenario how operator communicate or notify each other.Also suggest some good documents related.

      • @ryan.thanx. could you pls explain how billing made for these numbers?is there is any billing solution available in market for.

  2. Hello prasanna,fantastic work ,you summarized and explain all topic in nice way, could you please explain more about RA and fraud.

  3. just some additional info – nowadays simboxes are usually pun in vans or minibuses, so the location changes all the time..

    • Nowadays,we are working hard to indicate a new parameters that will check the MSISDN to it new Reuters that will help simbox fraud reduce.This is a new research which was conducted by the faculty of Sciences at University of People Computer research for data coding.

  4. Interesting, there is a company in the US by the name LATRO that actually hunts SIM Boxes. It seems that this is the only effective way of eliminating SIM Boxes since identifying the SIM Box and blocking it is only a temporary solution.

  5. By TCG test call generators for international calls . If SIM boxes are used the terminating mobile/fixed landline device would not see the CLI correctly.

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