For the past five years a mobile phone hacker ring has been buying and selling codes to unlock SIM cards. French authorities have finally busted this group according to a report by MSNBC.

So, what exactly is the point of stealing a SIM card code? Unfortunately, it can contain a lot of information that is very useful to criminals. Some of the things that can be found on your SIM card are:

• A unique serial number
• A unique number for the mobile phone user
• Security authentication information
• Ciphering information
• A list of services that you have access to as a user

Access to this information can provide criminals with enough data to use their mobile phones to make unauthorised or expensive calls using your SIM card information. They could also commit crimes using your number making it look like you’re the one who is doing the bad stuff. In extreme cases, criminals may even get enough information to commit full-on identity theft or even load surveillance software onto your phone to completely track your activity.

If you thought that this wasn’t a widespread problem, think again. The mobile hacker ring that was just busted reportedly bought and sold approximately 30,000 stolen phone codes per month over the past five years – that’s well over one million devices that have been affected by the group alone.

If you suspect that you have been a victim of SIM card information theft, the first thing that you should do is immediately remove the SIM card from your mobile phone. You should take both the card and your handset to your mobile phone service provider and let them know that you may have been hacked. They will give you a new SIM card.