Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The IMEI Code: Your phone’s other number

tedium.co

Post reply on HN
Print view View original

71–80 of 174 posts

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

#71

Post by chirau »

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 Samsung members. Paid for the phone, convinced it was a genuine one.

Upon registering it and using it, it becomes very clear the phone is fake and is at best a clone. The camera is nowhere near the S24 and does not have the features. It heats up after charging and does not keep charge. It runs slower than a 10 year Android once you are signed it.

when you run diagnostics, it shows all the specs of an S24 Ultra. How do I know this? I went and got another S24 Ultra from the store and they are worlds apart.

So my question is, if you are buying a phone from a reseller or someone, is there any way of definitely asserting whether it is authentic?

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

#72

Post by 6th »

medo-bear wrote: post #61
londons_explore wrote: post #30

Earlier quoted context omitted.

In Kazakhstan, when a phone is used on a mobile network for the first time, the IMEI of the phone gets locked to that mobile network and that sim card. When you buy the sim card, they photocopy your passport/ID card. No other sim will work in it until you take that photo ID/passport to the mobile companies office to have it unlocked. The photo id (even if expired) becomes the unlock code for the phone. Made phone the…

> Made phone theft drop to pretty much zero Use a nuke to kill a fly?

It was the only way to be certain.

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

#73

Post by yardstick »

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…

This is typically where consumer rights laws come into play and a key advantage of buying first hand from a “real” business rather than an individual or third party. At least there you have someone you can easily hold to account.

You need to price in the risk factor when purchasing where such legislation doesn’t apply or isn’t easy to enforce.

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

#74

Post by sfx2000 »

Interesting thread - as someone that used to be in carrier space...

IMEI - we only really cared about the TAC prefix, as this identifies the device type, which is mapped to capabilities for services.

IMSI - this is usually in the SIM card (UICC), and mapped out specifically within the uSIM/SIM application inside the card. This is aligned with the Billing/Rate Plan for services that the subscriber is set up with.

TMSI - this is usually what the network uses to page you and also deliver singaling over the NAS via the SGs interface for devices that do not support IMS/VoLTE

ICCID - this ID's the card itself, for SIM cards, it always starts with 89 as this designates the card as telephony related as a physical UICC - remember, there are other types of UICC's such as CHIP based Credit Cards, which start with a different number.

MSISDN - this is the number that you dial and send SMS to - in legacy systems, it can also be referred to as the MDN

Fun Fact that was skipped in the article - IMEI's that start with 99 are special, as these indicate that the Device is both GSM/UMTS/LTE and CDMA/EVDO capable, and generally those IMEI's will align closely with the CDMA MEID's, but they were not required to. The "99" range wasn't just Apple, but was used in the early days of dual-mode across most vendors as it helped facilitate session handovers from C2K to any 3GPP based service. For C2K, on the IMSI front, most devices would use IMSI_T (True IMSI based on the SIM card IMSIef) but some used IMSI_M which was based on the legacy MIN.

Legacy - there is the ESN in CDMA, but this is very legacy, and was largely superseded by MEID - for Legacy Support, pESN could be derived from MEID, however at the high risk of collisions...

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

#75

Post by tschwimmer »

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…

I’m sorry that this happened to you. The debugging and tear down sound like they would make for an extremely interesting blog post though. I encourage you to write it up and post it here - I’d definitely read it.

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

#76

Post by sfx2000 »

ementally wrote: post #4

You can use https://github.com/srlabs/blue-merle if you want to change your IMEI >The blue-merle software package enhances anonymity and reduces forensic traceability of the GL-E750 / Mudi 4G mobile wi-fi router ("Mudi router") >Mobile Equipment Identity (IMEI) changer >Media Access Control (MAC) address log wiper >Basic Service Set Identifier (BSSID) randomization >MAC Address randomization

I don't recommend mucking about with the IMEI, as you risk a collision with another device that is already using that IMEI - IMEI's are supposed to be immutable.

I realize that there are some Modem OEM's that might allow the IMEI to be "adjusted", but proper modem vendors will not allow that AT command.

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

#77

Post by thedougd »

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 the register. That worked well for a few years.

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

#78

Post by lmz »

skyyler wrote: post #44
ParanoidShroom wrote: post #32

Earlier quoted context omitted.

They are primarily used for configuring your visual voicemail lol. Stop the hyperbolic statements.

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.

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

#79

Post by mannyv »

I remember some telco guy saying “the IMEI is unique until it isn’t.”

We always wondered if you could crash part of a cell network by dropping in 8192 phones with the same IMEI. Everyone needs to deal with non unique identifiers, but the question is how many do they expect?

FYI this is a problem on Ethernet, when you get boards that haven’t been initialized. Things don’t like multiple MAC addresses with 0s.

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

#80

Post by kbolino »

boznz wrote: post #27
kbolino wrote: post #18

Earlier quoted context omitted.

A MAC address is 48 bits and an IMEI is about the same entropy-wise. That's not nearly enough room to avoid duplicates (even SLAAC requires duplicate address detection, and IPv6 has a lot more bits to work with). You'd need a whole new layer 2 protocol, though to be fair you might be able to strip it down to just doing collision detection/avoidance and leave addressing up to layer 3 with IPv6, but that's not going to…

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

Yes, but you could have hundreds of thousands of devices connected to that tower in a dense metro area. Even a single hardware address collision would result in both devices being unable to reliably reach emergency services.
Post reply on HN