In the past, many mobile phones came with 'default' PINs for accessing voicemails - the idea being that people would change the default PIN to something unique. If they didn't, the default PIN was all someone would need to get into a voicemail inbox. Needless to say, hacking used to be shockingly simple.
All you needed was the phone number of the person who's voice mail you wanted to hack and two phones of your own. Then you ring the number and while the person is on the phone you ring the same number with your second phone. This will put you through to their voice mail. Then you entered the correct PIN number and listen to the voice mail. The question you are asking is, "How do I know the PIN number?" I checked my land line, my mobile and my partners mobile and all three had a default PIN number of "0000". Piece of cake. I should note that I did change them all within a day or two of getting the phones.
The reason why I am posting this is because today we have heard about people who had their voice mail hacked all seem to be getting large sums of money because the didn't change their PIN numbers. That actually doesn't seem completely right to me. The user manual that came with the 3 phones mention above all warned me to change the PIN number so I would expect all the celebs getting large sums of money would have had the same warning in their phone's user manual.
A few years ago a friend of a friend's second cousin who had a mate at work who knew someone who had his car stolen. He was insured so wasn't too worried until the insurance company discovered he had parked it in the street unlocked and with the keys in the ignition and a laptop and camera lying on the back seat in full view. The insurance company quite rightly refused to pay out saying it was his own fault the car had been stolen.
OK, the thief and the phone hackers were the bad guys here but we all have a duty to go someway to protect our belongings and make it at least a little bit difficult for the bad guys to do the wrong thing.
PS I should point out that mobile phone service providers have taken steps to do away with the default PIN numbers. Now when you set up remote access to your voice mail most providers make you input a new PIN number and wont let you use "0000" or "1234"PPS. Have you set up remote access to you voice mail? Did you change the PIN number? If you didn't, are you going to change it now?