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78

Without access to the key, then the problem for attackers is the same as if there was no backdoor key: the attackers would have to break the encryption itself. But ... If we assume that the private key of the base station is secure Your base assumption is the one that requires challenge. That there is a key is the problem. key handling key misuse key ...


27

While I agree that every point of schroeder's response is true, there are two deeper issues that make it so much more dangerous than the current model of security. Right now, if you install an encryption key on a system, that key only controls your system and can only be accessed by the people you trust to access your system. Breaking into any system is ...


18

If there's a backdoor, it will be abused. The question is when, not if it will be abused. There are too many actors that could compromise such a system, and no easy way to plug the holes. If a private key leaks, it's done. It's cheaper to all involved to ignore the leak until there's a high profile case blowing to the press. Changing every key on every base ...


3

You have the other comments already. As a minor point, the list isn't quite correct in two areas: A5/4 isn't Snow 3G - it is a full length 128-bit key version of A5/3 using the Kasumi algorithm. See 3GPP TS 55.226. The Kasumi algorithm applied to GSM uses a 64 bit key bulked out to 128 bits for algorithm input. A5/4 extended that to using the full 128 ...


1

IMSI catchers essentially simulate cell towers. Nearby phones will try to use these fake towers in order to provide connectivity. But while normal cell towers usually act in the interest of their users fake cell towers might in theory misuse protocol features or send malformed protocol data in order to trigger bugs in the phones modem. Given that the modem ...


1

No. ISP cant see MAC address of your router. MAC is a layer 2 address which exist within the network only. And yes, your ISP will see only the IMEI.


1

The IP part of the cellular connection is added down the line somewhere in the core network (the BTS is pretty much just a dumb radio frontend), so the phone can't directly reach the base station over IP by looping back inside the BTS, as it does not talk IP to the phones. However in case of misconfiguration nothing prevents the phone from accessing the BTS ...


1

IMSI is just a single method in which a MITM attack could take place. Most of the time a IMSI catcher is fairly passive in that it wants to see RX/TX data and proxy it to the proper tower for full functionality as to make sure the user has no clue. However, it can also be used as a DOS tool as well where it can become more of an active attack tool if need be....


1

it possible to somehow hack the signal from dongles or internet that is there on the phones Yes, definitely. The most economically feasible attack would be a man-in-the-middle with an open source SDR transciever This paper has an excellent implementation with a USRP, attacking 4G with commercially available open-source tools. Here is a video of this ...


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