Once I was told that you can identify if your mobile phone is being tracked by someone (e.g. police), by calling placing a specific prefix to the number. This prefix in my country is normally reserved for for landline phones, not for mobiles.

I tried it for many mobiles, including mine, and all I get is just a "beep", not wrong subscriber message, nothing.

Recently one friend of mine has some minor law problems, and suddenly if I call his number including the prefix, it not only calls normally, but also a lady picked up the line, asking who I am. Every time we called her, when she realized that we were not the one she was wanting to call her, she was hanging up, without explaining who she is.

I believe that my friend's calls are intercepted by someone, and that in fact I talked to the attacker. This behavior is constant no matter where my friend is (so no over-the-air man-in-the-middle attack), and with any mobile phone (so no spying app, or hacked electronics).

Who can we identify the attacker, and/or make sure that my friend will get out of all these?

  • 6
    I have to say, that sounds like an urban legend. Any kind of covert surveillance would not give you a convenience number to call to unmask them. Also, you may be harassing someone accidentally, because it may be a valid phone number (you said the prefix is for landlines -- you may be calling someone's house!). You should probably stop calling this person.
    – Ohnana
    Dec 17 '15 at 15:41
  • Of course I checked whether this number exists, and if it is a valid number, but it isn't! Furthermore, including the prefix the number is now 13 digits which is normally invalid for my country. Dec 18 '15 at 7:57
  • What is the country, and what is the prefix? 13 digits Is invalid for your country, but depending on what the first few digits are it may be valid for another country.
    – tbernard
    Dec 18 '15 at 22:27
  • I am in Greece and the prefix is 210 Dec 22 '15 at 9:49

Phone tapping that isn't done by physically altering the two phones themselves is done by plugging into various access points in the network between the two phones. These access points are controlled by A) phone service providers or B) governments. Neither of them are likely to have (nor would they want to) a number or prefix or other method of checking what access points your call is routed through.

The only conceivable way I could see the intended situation happening is possibly if you're entering a prefix meant for network technicians to use to diagnose the network. But this is very very unlikely, especially since you had someone answer.

This mysterious prefix is probably an area-code or maybe another country-code(!). Watch for long distance charges on your bill now.

Some phone providers do provide you with prefixes to do things like mask your number from the caller id of someone you're calling, but this would have no affect for someone hacking your phone or the phone network.

  • Just today, after many calls pretending not to know anything and that the call was a mistake, the person said that the call reached a ministry, but didn't said which. It is a phone number in my country as it seems, and possibly in the same city with us. Just to note, the connection/audio quality was not that good, with some kind of "noise". Dec 18 '15 at 8:02
  • I obviously wouldn't know the details of your country's phone exchange systems. However what I've describe above is the baseline that most systems are built on. What I do know is that someone tapping a phone line would actually have to go through more effort to leave a callback number like this instead of staying anonymous. If there is such a prefix that would mean there's some legal reason your country 1) allows tapping and 2) requires the phone tappers to be reachable. The first is a possibility, the second very very unlikely since the point of phone tapping is usually to stay hidden
    – tbernard
    Dec 18 '15 at 22:31

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