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The IMEI Code: Your phone’s other number

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Re: The IMEI Code: Your phone’s other number

#81

Post by sfx2000 »

tjohns wrote: post #62
lxgr wrote: post #51

Earlier quoted context omitted.

> As far as I remember, the ICCID never actually appears in standard network messaging. Yeah, that would be the IMSI (which a given SIM card can have multiple of, e.g. for switching to a more beneficial home network while roaming!) The ICCID is useful for identifying a given physical SIM card (e.g. so that the phone can link a given user-selected profile name to it/the associated phone line for a "preferred line for…

At least in the US, the 911 infrastructure is dated. In older systems, your caller ID is sent using in-band DTMF tones, which are decoded by the dispatch computer. On newer E-911 systems they get some additional digital address data from the telephone network, but the record format wasn't designed with VoIP or cellular in mind. So in those cases, the telephone network sends a virtual number and the dispatch computer…

Gosh, yes it's a bit of a mess...

The PSAP (E911 end point) likely will receive an MDN/MSISDN (10 digit number you dial for NANP networks) - this is so they can call back if the call is dropped.

E911 is a special service, so in the case of deactivated/missing SIM cards, the carrier assigns a temporary MSISDN for duration of the call when the UE exits E911 mode - there are actually of regulatory and carrier requirements around E911 mode.

E911 Phase 2 required not only the DN, but also if possible the location of the device - whether thru Cell Base Station Triangulation (if possible) or GNSS with a LAT/LONG based on coarse/fine location info.

In any case, as @tjohns mentions, IMSI/IMEI are not typically used outside of the servicing network.

Re: The IMEI Code: Your phone’s other number

#82

Post by wrboyce »

ale42 wrote: post #52
nolan879 wrote: post #29

Earlier quoted context omitted.

Carriers have been blacklisting IMEIs for at least 10+ years. Since phones tended to be carrier-locked back then you couldn't go to a new carrier without being in good standing to get your device's unlock code from the old carrier. Now that devices are available unlocked by default, it is probably harder since it would require carriers to communicate IMEIs?

Not sure, I think that there are international lists of stolen IMEIs. Maybe it's just in Europe, though.

~15 years ago the blacklists were certainly shared within Europe, but there was an intercontinental trade of blacklisted phones from Europe to Africa (and, if memory serves, Asia).

Re: The IMEI Code: Your phone’s other number

#83

Post by lxgr »

tjohns wrote: post #62
lxgr wrote: post #51

Earlier quoted context omitted.

> As far as I remember, the ICCID never actually appears in standard network messaging. Yeah, that would be the IMSI (which a given SIM card can have multiple of, e.g. for switching to a more beneficial home network while roaming!) The ICCID is useful for identifying a given physical SIM card (e.g. so that the phone can link a given user-selected profile name to it/the associated phone line for a "preferred line for…

At least in the US, the 911 infrastructure is dated. In older systems, your caller ID is sent using in-band DTMF tones, which are decoded by the dispatch computer. On newer E-911 systems they get some additional digital address data from the telephone network, but the record format wasn't designed with VoIP or cellular in mind. So in those cases, the telephone network sends a virtual number and the dispatch computer…

Good point, and implementing a "this IMEI calls 911 to ask for the time of day every hour" block on the side of the networks seems risky as well, so I get how it might not be that helpful.

But then I wonder why having an IMSI (as far as I understand, the SIM can be deactivated, foreign etc., i.e. it doesn't need to actually register to the network) improves this in Germany?

Maybe German authorities just hope that having to insert a SIM might deter people, since SIMs are perceived as being personally identifiable more than just phones without a SIM?

Re: The IMEI Code: Your phone’s other number

#84

Post by sfx2000 »

thedougd wrote: post #77

Many a year ago, when the iPhone was new and Android was on version 1.6. Sprint offered the SERO plan, an unlimited plan for friends and family. When smartphones hit, they would no longer allow the SERO unlimited plan to transfer to the new phones. The HTC phones had a Qualcomm radio that, with the right tooling, one could write all 0s to the IMEI (or the CDMA equivalent) register. Then you could write any IMEI to th…

SERO was one of the Sprint Rate Plans, the other was the Pioneer Plan for early adopters on SprintPCS

HTC got into a bit of trouble with the carriers on the whole IMEI/MEID rewrite mess at the end of the day. With Qualcomm, that was an NVITEM that was supposed to be read-only.

Re: The IMEI Code: Your phone’s other number

#85

Post by sfx2000 »

chirau wrote: post #71

Is there any entity or procedure that actually proves what a phone is what it claims to be? Unfortunately, neither IMEI, Serial Number or a combination of both can assert this. I bought a Samsung S24 a week ago off Facebook Marketplace. It was in the box and everything. I cross checked both the IMEIs and also the Serial Number with the #06# test. I even checked them online. Did all the tests, #0 # and even downloaded…

The carrier can ID the device type by the radio layer itself at the PHY layer.

Re: The IMEI Code: Your phone’s other number

#86

Post by fsckboy »

lmz wrote: post #78
skyyler wrote: post #44

Earlier quoted context omitted.

https://www.heise.de/news/Zoll-BKA-und-Verfassungsschutz-ver... Not sure where you get your information, but these are routinely used by police to covertly track targets.

Just because they are routinely used for such does not mean it is their primary purpose.

when we know that govts want this capability, when we know that govt regulators are in the same room with telcos when plans are being drawn up, when we know govt uses these capabilities routinely, why would you doubt it was there for that purpose? isn't this a good time to round up the usual suspects? If the govt intervenes to get this capability and also declares that this should not be the primary purpose, I guess that would make it a secondary purpose? OK, I feel better now, phew!

Re: The IMEI Code: Your phone’s other number

#87

Post by kbolino »

baby_souffle wrote: post #39
boznz wrote: post #27

Earlier quoted context omitted.

Surely the uniqueness is only required at the bottom end of the stack before the first 'router' ie the cell tower

> Surely the uniqueness is only required at the bottom end of the stack before the first 'router' ie the cell tower Not if you need to send a message to $thatUniquePhone. Over simplifying considerably, but if a land line places a call to a mobile, the "220-1234 calling for 220-7890" message enters the network. The `220-7890` phone number needs to map to the unique modem address so you can look up which tower the call…

Assuming something like VoIP is in use, you reach other devices with their IP addresses, not MAC addresses.

Re: The IMEI Code: Your phone’s other number

#88

Post by m463 »

thedougd wrote: post #77

Many a year ago, when the iPhone was new and Android was on version 1.6. Sprint offered the SERO plan, an unlimited plan for friends and family. When smartphones hit, they would no longer allow the SERO unlimited plan to transfer to the new phones. The HTC phones had a Qualcomm radio that, with the right tooling, one could write all 0s to the IMEI (or the CDMA equivalent) register. Then you could write any IMEI to th…

didn't I read recently about some manufacturer that shipped many of its phones with the same imei?

EDIT: "Over 13,000 Vivo phones found to be using same IMEI number"

https://www.techradar.com/news/over-13000-vivo-phones-found-...

Re: The IMEI Code: Your phone’s other number

#89

Post by ikekkdcjkfke »

least wrote: post #28
mytailorisrich wrote: post #8

Earlier quoted context omitted.

There is no privacy concern, really, as this is unique to the device, not subscriber, and only shared with the network operator, who obviously already "tracks" the subscriber through the SIM , which contains the subscriber identifier (IMSI). On the other hand, the IMEI in principle makes tracking and disabling of stolen devices easy. By the way, in the UK it is actually an offence to change the IMEI [1] [1] https://w…

This is 100% a privacy concern if you're dealing with state level actors.

Dudes have been driving around with fake base stations, rare, but has happened. Only sent spam sms messages with links but could be expanded with buying data from data brokers. A really serious crime though

Re: The IMEI Code: Your phone’s other number

#90

Post by lloydatkinson »

kevvok wrote: post #65
BuildTheRobots wrote: post #2

Couple of thoughts > The combination of the ICCID and the IMSI basically tells the mobile network, “hey, this person paid for a plan.” As far as I remember, the ICCID never actually appears in standard network messaging. It might be possible for the network to request it, but it's not part of a standard 2/3/4/5g attach. The piece seemed to miss two major uses for the IMEI (or I missed it when reading), which were wor…

> Radio firmware and state machines have always had weird bugs, and even when it conforms to standards (some of which are extremely interpretable), does very weird things in the real world. Pre-smartphone, being able to update phone and radio firmware was extremely rare, so it was common for the networks instead to implement workarounds on a manufacturer or handset basis. Having a hardware ID that identified this was…

Only two digits? What could possibly go wrong... again.
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