INITIALIZING_ACCESS_PROTOCOL...
Scan the smartcard reader connection interface and establish a session with the inserted SIM card. The system checks for basic communication compliance (ISO 7816 parameters) and queries the card's Answer To Reset (ATR) bytes to determine the operating voltage, clock rate, and vendor-specific configuration profiles. This handshake is critical to ensure that communication speeds and protocol formats (T=0 or T=1) are matched accurately, avoiding transmission errors during subsequent commands.
Enumerate active Toolkit Application References (TAR) and perform APDU command fuzzing. The tool sends formatted APDU packets across a range of 130+ standard TAR destinations, checking for undocumented application endpoints. It evaluates the card's response to identify unprotected SIM applets and misconfigured Access Control Rules. By observing the status words returned by the SIM card, the utility catalogs potential entry points that require cryptographic keys or suffer from implementation bugs. For researchers auditing how baseband firmware handles these OTA commands in virtual environments, refer to the FirmWire emulation platform.
Execute Over-The-Air (OTA) passthrough simulations. The system audits how the SIM card handles secured SMS packets (using mechanisms like SMS-PP). It checks if the SIM correctly decrypts, authenticates, and rejects invalid command packets, or if signature verification can be bypassed to execute unauthorized applets. The tool simulates packet injection attacks to verify that command packaging layers comply with TS 31.115 and TS 31.116 specifications.
Auditing SIM card security requires establishing a local PC/SC smartcard interface. Fuzzing APDU commands and scanning Toolkit Application References (TARs) can result in permanent SIM locks if too many incorrect administrative keys (ADM) or invalid codes are sent. Researchers are advised to only test on programmable developer/test SIM cards with known credentials and avoid executing scans on live subscription-active consumer SIM cards.
Ensure compliance with carrier agreements and telecommunication policies. Accessing administrative folders (such as EF_IMSI or key-sets) without the network operator's consent violates service agreements. All testing must be conducted locally using physical smartcard readers connected to your secure workstation.
You've executed the basic steps for SIMtester. The TelcoSec Academy offers full hands-on simulation labs, baseband source code auditing, and deep cellular signal processing certification courses.