I am trying to find out if there is a way to detect the IMSI # of a phone that is calling you. So say for example, caller A calls person B- person B wants to know A's imsi #. I thought I read this information is transmitted to the MSC- is there a way to ask the MSC for that information?
A:
An IMSI number (International Mobile Subscriber Identity) is a unique number that is private.
It is not sent to other phones, a randomly generated TMSI is sent instead.
This is because the IMSI number could be used in forging SIM cards and eavesdropping on phone calls. It is not possible to obtain the IMSI by any normal procedures and doing so would be illegal.
Mervin
2010-06-23 18:46:11
Thanks. I'm working on a research project this summer to detect spoofed caller ID, and I thought if I was able to get the IMSI of the incoming call, and then use that to look up the number associated with that IMSI #, then compare the displayed caller ID number with the number associated with the IMSI number I'd be moving forward with the project.
LDCodes
2010-06-23 19:14:20
I'm afraid it's not possible then since the IMSI is not sent to other phones and the TMSI is random (and probably only to obtain with surveillance/wiretapping devices). You can however get your own sim card's IMSI though it would not be of any use.You could research security weaknesses of intercepting GSM communications between a phone (your phone to make it legal) and the GSM tower, since there are articles on that it might also be a lot easier.
Mervin
2010-06-23 19:37:02
That sounds like it could be a promising topic for the fall!
LDCodes
2010-06-23 21:22:04
A:
I'm not 100% agree with previous answer. Yes, it is impossible to obtain IMSI of the phone calling you. Pairs IMSI - MSISDN (phone number) pair are stored in the HLR.
But it isn't illegal to obtain IMSI by normal procedures. If you have physical access to the card you can just read EF IMSI. It isn't protected at all. Probably prev. author mentioned that it would be illegal to obtain IMSI of remote phone. If so, yes, it would be illegal because you'll need to have an access to MNO's servers.
OgreSwamp
2010-07-27 13:39:59