Back in the first-gen CDMA days, I copied the ESN from my phone to a second phone of an identical model (a friend was upgrading his). I tried calling them the number when they were both on and next to each other, and they both rang. Answering both allowed me to hear audio in both phones for a short time, until something got out of sync and the call would end.
Leaving one off, the other would work normally. It was a great way to have a backup phone when cell plans used to cost $70/mo and phones were locked to carrier accounts.
I feel like this is the TV detector van[1] equivalent of cell phone companies. It might be possible to implement, but I doubt it's widely implemented as the article suggests, if at all.
I got to say, to me it seems rather ... unlikely that this is used on a wide scale. The differences in mass produced hardware must fall within a fairly small distribution, and they only mention rise-time as a measurable variable. Taking into account other variations like temperature and device aging, and I have a hard time believing that these fingerprints are highly unique or stable over time.
In addition it seems unlikely that your average receiver hardware could even pick up such details. These are super low-level details observable only at the lowest level of the radio stack.
There's also no sources cited that this is used on a wide scale. To me, I would put this in the bucket of hypotheticals (like the power company stealing your data from your PC based on voltage fluctuations from your laptop). Perhaps barely physically possible, but not really worthwhile.
(unless of course the fingerprints are put there intentionally and secretly... like the yellow dots from printers)
I know nothing of radio communicaion, but having slight variations on some part of network negotiation might limit conflict between devices. The same ways you would add some radomization on broadcast responses on networking, or auto-reconnect, but in a low level, on hardware manufacturing. This could be a easy to track, recognizable signature with standard antenna hardware.
Back in the day I found a guy who cloned the identity of my analogue portable cell phone with my in-car cell phone so they both behaved as the same number. When one rang, they both rang.
In theory when I answered a call on one, the network would be signalled to say I'd picked up and it would stop telling the other to ring - but once in a while the other phone would keep on ringing .
iirc phone cloning may have been illegal here in the UK at the time...
That's interesting. Slightly off topic, but this seems to reveal a small error in the movie Primer.
The two main characters travel back in time one day to use their knowledge of the stock market to make money on some good trades. Their doubles are of course also in the past, so they make efforts to avoid them at all costs so that they don't interfere with causality.
One of the characters mistakenly brings his cellphone with him back in time. When his wife calls, they assume that since the his phone is ringing that the double's phone couldn't be ringing, so he decides to answer it and pretend to be at work as his double is.
Around 7 years ago I had a Galaxy S2 on Sprint (CDMA) and home internet via ClearWire. Sprint and Clear both used the same WiMax network (same cell towers) for '4G.' My phone was rooted so I could mess around with some normally locked settings, and at some point phone service for my S2 was cancelled.
One day I changed the APNs (which virtual network the phone connects to via its radio) from the default Sprint ones to the Clear ones, and also changed the MAC address (might not be the exact term, but WiMax 4G was basically long-range WiFi and so the device had a sort of MAC address). Even though my phone's service had been cancelled, I was able to use internet from the Clearwire plan. Of course no phone calls / text messages.
It worked as long as I was at home - I think they both connected to the same cell tower and so couldn't be distinguished.
> There are various methods used to obtain the IMEI. The most common methods are to hack into the cellular company, or to eavesdrop on the cellular network.
Or on Android, go in settings, about phone, and tap MEID. There should be an equivalent on iPhone. The MEID and IMEI are not secret at all. They just identify that particular phone.
The part that one would want to clone is the subscriber part anyway, not the equipment ID.
> A GSM SIM card is copied by removing the SIM card and placing a device between the handset and the SIM card and allowing it to operate for a few minutes and extracting the Ki, or secret code.[citation needed] This is normally done with handsets that have the option of an "extended battery" by placing the normal size battery in the handset and the Ki in the now vacant extra space. This is done by allowing the device to log the interaction between the mobile telephone switching office and the handset.
The Ki is just a cryptographic key (not a physical thing as the article would imply by it needing "vacant empty space"), and is not exposed on the wire protocol between the handset and the SIM card. The handset forwards cryptographic challenges from the mobile network to the SIM card, and the SIM card answers with the correct answer to the handset, which then replies to the network.
Even then, it doesn't make sense to do that. Three letter agencies can just go ask the phone company for a wiretap.
Cloning the equipment ID is also useless on its own, you'd want to clone the subscriber identification, which is the part that says to the network that you're the device for this subscriber. It's how moving a SIM card to a new phone makes the new one ring and the old phone stay silent when calling the number associated with it.
Three letter agencies can just go ask the phone company for a wiretap in their country . They are also interested in performing similar tasks elsewhere in the world ;)
The Ki can be derived by interacting directly (electrically, not remotely) with the SIM for a few hours, at which point it's possible to clone the SIM.
18 comments
[ 3.3 ms ] story [ 33.9 ms ] threadLeaving one off, the other would work normally. It was a great way to have a backup phone when cell plans used to cost $70/mo and phones were locked to carrier accounts.
[0] https://en.wikipedia.org/wiki/Radio_fingerprinting
[1] https://en.wikipedia.org/wiki/TV_detector_van
[1] https://en.wikipedia.org/wiki/Operation_RAFTER
In addition it seems unlikely that your average receiver hardware could even pick up such details. These are super low-level details observable only at the lowest level of the radio stack.
There's also no sources cited that this is used on a wide scale. To me, I would put this in the bucket of hypotheticals (like the power company stealing your data from your PC based on voltage fluctuations from your laptop). Perhaps barely physically possible, but not really worthwhile.
(unless of course the fingerprints are put there intentionally and secretly... like the yellow dots from printers)
In theory when I answered a call on one, the network would be signalled to say I'd picked up and it would stop telling the other to ring - but once in a while the other phone would keep on ringing .
iirc phone cloning may have been illegal here in the UK at the time...
The two main characters travel back in time one day to use their knowledge of the stock market to make money on some good trades. Their doubles are of course also in the past, so they make efforts to avoid them at all costs so that they don't interfere with causality.
One of the characters mistakenly brings his cellphone with him back in time. When his wife calls, they assume that since the his phone is ringing that the double's phone couldn't be ringing, so he decides to answer it and pretend to be at work as his double is.
In reality it seems both phones would have rung?
One day I changed the APNs (which virtual network the phone connects to via its radio) from the default Sprint ones to the Clear ones, and also changed the MAC address (might not be the exact term, but WiMax 4G was basically long-range WiFi and so the device had a sort of MAC address). Even though my phone's service had been cancelled, I was able to use internet from the Clearwire plan. Of course no phone calls / text messages.
It worked as long as I was at home - I think they both connected to the same cell tower and so couldn't be distinguished.
The sim card allows you to connect to the same physical cellular network.
The APN gave you access to a virtual network inside this physical network where they didn't check you had the right to use it.
For example:
> There are various methods used to obtain the IMEI. The most common methods are to hack into the cellular company, or to eavesdrop on the cellular network.
Or on Android, go in settings, about phone, and tap MEID. There should be an equivalent on iPhone. The MEID and IMEI are not secret at all. They just identify that particular phone.
The part that one would want to clone is the subscriber part anyway, not the equipment ID.
> A GSM SIM card is copied by removing the SIM card and placing a device between the handset and the SIM card and allowing it to operate for a few minutes and extracting the Ki, or secret code.[citation needed] This is normally done with handsets that have the option of an "extended battery" by placing the normal size battery in the handset and the Ki in the now vacant extra space. This is done by allowing the device to log the interaction between the mobile telephone switching office and the handset.
The Ki is just a cryptographic key (not a physical thing as the article would imply by it needing "vacant empty space"), and is not exposed on the wire protocol between the handset and the SIM card. The handset forwards cryptographic challenges from the mobile network to the SIM card, and the SIM card answers with the correct answer to the handset, which then replies to the network.
Cloning the equipment ID is also useless on its own, you'd want to clone the subscriber identification, which is the part that says to the network that you're the device for this subscriber. It's how moving a SIM card to a new phone makes the new one ring and the old phone stay silent when calling the number associated with it.
People cloned phones to make free calls, not receive them — like a '90s/2000s version of blueboxing: https://www.pressherald.com/2010/04/19/woman-finds-cell-phon...