Under certain circumstances, if you lose sight of your mobile telephone, then you may reasonably assume it has been compromised. These circumstances are more common than you might think. Here are two cases of this that I have encountered over the last year or so.
The first was when the Border Guards took away a client’s mobile phone to ensure that it was “legal” in the country he was entering. They returned it a few minutes later saying it was “legal”.
In the car on his way to the hotel our client took off the battery and removed the chip. He didn’t use or carry the phone for the rest of his trip. Upon his return home he had the phone examined. The battery had been swapped for one that turned it into a mobile bug and tracking device.
The second client had similar alterations done to his phone while he was having a shower in his hotel room. Later, he remembered that it was on the wrong side of the night stand when he retrieved it before going to dinner.
The tampering was discovered by his corporate security staff while he was in a meeting. The Security Guard took the battery out and placed the phone on the table in front of him at the entrance of the meeting room. Without anything to do, the bored Guard was staring at the batteries of two identical phones and noticed that a label was on upside-down on one battery. This prompted him to have both phones examined.
This client now knows why things had not been going well with his project during the weeks since his overseas trip to meet with a potential supplier.
Tin Foil Hat
Now some mobile telephones like the iPhone have an integral battery that can’t be changed, but these smartphones can be loaded-up with malicious software. It has been suggest that you fashion a tin foil hat for your cell phone to thwart tracking and eavesdropping.
Faraday Cage Cell Phone Wallet
A Faraday Cage is a grounded metal cage with holes that are smaller that the RF wave length from which you wish to be shielded. A tin foil wallet might shield the cell phone and prevent it from receiving or sending signals.
I haven’t tried this but it might work with a a little tinkering, even though it isn’t grounded, due to the week signal strength of cell phones.
Detecting a Cell Phone Bug
The following video about cell phone bugs, and related topics, begins by listing some ways to detect a mobile telephone altered to become a surveillance device.