It would depend on the type of phone.
For BlackBerry, Android or iPhone – without getting too much into a legal gray area – there are a few different ways to tell. If you don’t mind being “a little bit paranoid” or controversial, follow these steps below!
Step 1) Pull up your contact list and look for any contact who you haven’t communicated with lately but who ostensibly should be in touch; call them to see if they pick up. Alternatively, send text message. Note the time that this “check point” was conducted and compare it with future communications for differences in timing. Also be sure to check for an increase in carrier charges at this time because it could indicate that your phone is being tapped.
Step 2) Have a friend from outside the US send you an SMS with their area code. If you can’t do this, have them call you and when they hang up, see if your phone company has a post-call survey that asks if your service was satisfactory or not.
Step 3) Quickly turn off Bluetooth on your device and go to Settings > Wireless Controls > Mobile Networks > Network Operators . See if there is a different carrier listed here, but hidden. If you find one, someone could be using it to intercept your data. So change it back pronto!
Step 4) A third way would be to run a packet sniffer from an operating system other than Windows… This will allow for more granular searches than Windows does.
Step 5) A fourth way to do this would be to use a packet sniffer/protocol analyzer, like Wireshark , which is for Windows and Linux users. You can download it here . However, unless you are familiar with this already or have someone who IS familiar with it explain the output, you may not know what you’re looking at.
Once your phone has been determined “tapped”, take out the battery if possible (not all phones allow this) – because the tap only works while plugged in – and make sure that your contacts change their behavior accordingly; i.e., never discuss sensitive info over SMS again!
