I'm new to SIM Cards and there is something I don't understand. Are all SIM Cards reprogrammable? If I try to reprogram a SIM Card given by a Network Operator (let's say from AT&T), can I use a standard USB smart card reader?
I ordered blank reprogrammable SIM cards for home tests. And I can reprogram IMSI, K, etc. if I use the correct ADM key.
Therefore, I was wondering what kind of protection have real SIM Cards given by Network operators. If I know their ADM key, can I reprogram their cards?
I was wondering what kind of protection have real SIM Cards given by Network operators
Only small portion of files on SIM's file system is writeable after they are manufactured (these includes, but not limited to phone book directory, SMS messages, ...).
Knowing ADM doesn't change that fact. That's main protection barrier.
Also, some of authentication/encryption parameters (Kc, IMSI) are also stored by operator in HLR. So even if you manage to modify data on SIM, challenge-response authentication will simply fail when card will try to authorize with network.
I recommend to read "Digital cellular telecommunications system (Phase 2+);Specification of the Subscriber Identity Module - Mobile Equipment (SIM - ME) interface(GSM 11.11)" specification (or its successors ETSI TS 100 977 and ETSI TS 151 011):
