It is a common rule that when there is a good thing, by default there is a bad thing associated with that. This applies to everything in this world. The mobile communication technology which gave us immense potential to grow had its disadvantage from the beginning. As its ability and merits are increasing, so are the drawbacks. On of the security threat was SIM card cloning where the module can be cloned and the call to the original SIM card can be received by the cloned cards and can share the same account.
Now the mobile security threat has gone a step ahead, the IMEI (International Mobile Equipment Identity) [to know your mobile IMEI number press (or dial) *#06# ] number which supposed to be unique and tamper-proof can be changed. The hackers have developed technology to change the IMEI number which otherwise can be used to track down the stolen mobile phone.
So folks better be careful with your all-in-all gadget and I whish you a happy conversation.