Listening to cell phone calls ?

[Jomba]

Hello,

Is there a way to tell if your cell phone calls are being listened to? I'm not talking about through spyware, I am talking about an order through the provider to record or an agency listening.

Regards,

Jomba

[digip]

Not really. If anyone was listening to your calls, you wouldn't really be able to tell depending on the type of phone and what they did to snoop the call. Some phones though, when attacked, force the phone down to pre 3G connection protocols and such, which would show your phone change connection modes(if the phone has indicators for it) and allows breaking the encryption on the phone to snoop calls since the older standards are less secure and outdated, but if an agency has a warrant, they can do so from the cell company to tap the call without any way of you knowing other than a copy of the warrant.

[Pwnd2Pwnr]

Funny thing; and DIgip, tell me if I am wrong; but aren't their antenna arrays on some bigger police stations in which could allow a "Syphon" of a cell phone signal? I think only the Police and Cell Phone companies could actively listen.

SMS on the other hand...

[digip]

You'd need a USRP or some other SDR setup that can listen in on the cell towers, but also impersonate them, so you can intercept the signal, or overpower the cell towers signal. In close proximity, much easier to do, like at hacker conferences when they hack everyones phones, its because the equipment they use is much closer to the end user than their cell towers are. Check out some of Georgia Weidman's talks and also, I think Darren has covered a few shows talking about the same topic. There are ways to setup your own custom GSM base station too, but that only works for GSM based phones and not CDMA phones I beleive. My phone is CDMA based, so not sure how that hack works(or the GSM for that matter) but I know it can be done.

Doing it from the police station, probably wouldn't work, other than if they had direct access to the cell companies systems and were fed the info. Antennas at police stations, are usually for their own network and radios in their vehicles.

Edited December 9, 2012 by digip

[Jomba]

Thanks for the replies. I suppose this would have been a great question to ask Kevin Mitnick when he was a guest, a while back. I'm also wondering if a Linux box could be built that would be dialed into and could run a test or tests to determin such tapping?

[digip]

Thanks for the replies. I suppose this would have been a great question to ask Kevin Mitnick when he was a guest, a while back. I'm also wondering if a Linux box could be built that would be dialed into and could run a test or tests to determin such tapping?

Kevin mostly listened in to the actual phone switching stations if I recall. More messing with the wired side vs the actual wireless side, but that was also like 20 or more years ago and technology is vastly different these days. Much of todays phone systems are computerized now and you can do a lot with a home VOIP box and asterisk and various service providers, but that as far as I know doesn't do much for cell phone systems, other than maybe identifying the base station, which might be able to show the equipment name, and in effect be compared with that of the real local switch once the cell company signal gets from the air, back to ground based communications, but you'd need the call to go through a wired signal somewhere, vs to your cell phone to see that info. http://tnid.us for example can show who the phone company is and equipment name in use for a specific phone number in most cases. Not sure how that info shows up to an asterisk box or if any of that is in the wired info you can tap into, but if so would be curious to see how that compares with a faked base stations info or intercepted transmission. Granted, tnid is usually cached data, and not always 100% accurate. My mothers number for example shows as Verizon, but shes on comcast cable, and her previous phone company was not Verizon at all, but in our area, most all of the actual equipment is verizon owned and leased to other telcos. When I had a landline, I used a different phone company, but when needed line services, Verizon was sent out to fix it since it was considered their equipment, so that may be why hers shows up that way. Edited December 10, 2012 by digip