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Did 5G kill the IMSI catcher?

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Re: Did 5G kill the IMSI catcher?

#3

Post by lxgr »

I've always been wondering: Is there a SIM card configuration flag that allows telling the phone to never even attempt an attach using a given technology?

This would allow leaking identifiers (at the cost of greatly reducing roaming coverage, at the moment), attaching to spoofed networks (for 2G, which does not have mutual authentication) etc.

Re: Did 5G kill the IMSI catcher?

#6

Post by jeroenhd »

Criminal IMSI catchers are pretty much dead, but with the aid of carriers law enforcement can still use similar technology even with full standalone 5G networks. I don't know how often unauthorized IMSI catchers are used in the wild, but I doubt it's a relevant percentage of the total amount of IMSI catchers out there.

Thanks to mmWave and beam forming, 5G allows operators to practically track you down to the exact centimeter in 3D space. Furthermore, depending on how willing the firmware of your modem is, the signal used to transfer GPS coordinates to the carrier for emergency response situations can also be triggered remotely by carrier hardware.

Basically, who needs IMSI catchers when you can just see all of the information you'd get from them remotely on a computer screen on the other side of the country?

Of course this is great to protect against criminals that are looking to find your personal phone number or whatever by showing up to your doorstep, but for the vast majority of cases, IMSI catchers are defeated because they're no longer necessary.

Re: Did 5G kill the IMSI catcher?

#8

Post by lxgr »

jeroenhd wrote: post #6

Criminal IMSI catchers are pretty much dead, but with the aid of carriers law enforcement can still use similar technology even with full standalone 5G networks. I don't know how often unauthorized IMSI catchers are used in the wild, but I doubt it's a relevant percentage of the total amount of IMSI catchers out there. Thanks to mmWave and beam forming, 5G allows operators to practically track you down to the exact c…

> depending on how willing the firmware of your modem is, the signal used to transfer GPS coordinates to the carrier for emergency response situations can also be triggered remotely by carrier hardware

Do you know if (at least some) basebands actually limit network-side location requests to emergency call/text situations only?

Re: Did 5G kill the IMSI catcher?

#9

Post by jeroenhd »

lxgr wrote: post #3

I've always been wondering: Is there a SIM card configuration flag that allows telling the phone to never even attempt an attach using a given technology? This would allow leaking identifiers (at the cost of greatly reducing roaming coverage, at the moment), attaching to spoofed networks (for 2G, which does not have mutual authentication) etc.

SIM cards don't connect to networks, the phone modem can just disable support for such protocols. That'd probably be illegal, though, in case you're trying to call emergency services and don't have 5G reception.

Some Android phones have a setting to at least disable 2G and you can easily configure them to a "preference" of only 5G. I believe iPhones have a 2G toggle as well if you enable lockdown mode.

It'll be years before you can reliably get rid of 4G without losing coverage, though.

I don't know about any such settings on mobile platforms such as watches, though. I also doubt cars have a setting for this (maybe if you use one of those Chinese Android-tablet-with-a-car-skin systems?).

Re: Did 5G kill the IMSI catcher?

#10

Post by lxgr »

jeroenhd wrote: post #9
lxgr wrote: post #3

I've always been wondering: Is there a SIM card configuration flag that allows telling the phone to never even attempt an attach using a given technology? This would allow leaking identifiers (at the cost of greatly reducing roaming coverage, at the moment), attaching to spoofed networks (for 2G, which does not have mutual authentication) etc.

SIM cards don't connect to networks, the phone modem can just disable support for such protocols. That'd probably be illegal, though, in case you're trying to call emergency services and don't have 5G reception. Some Android phones have a setting to at least disable 2G and you can easily configure them to a "preference" of only 5G. I believe iPhones have a 2G toggle as well if you enable lockdown mode. It'll be years…

> SIM cards don't connect to networks

SIM cards have hundreds of various configuration knobs influencing what a (compliant) baseband does, so I wouldn’t be surprised if there was one that does just that.

That said, some knobs are frustratingly missing, though – why is manually entering an APN a thing, but the default SMSC can be stored on the SIM?

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