The SIM Simulator is an open-source tool to help in performing security assessments on the mobile communication interface of IoT devices.
Some IoT device will only perform large transfers of data when connected over an high speed mobile network (3G or 4G), and intercepting these communications is impossible without replacing the SIM card. However, some modems will reject custom SIM cards. For this reason, a tool able to replicate the original SIM card but with modified keys was developed. SIM simulator can also be used to fuzz the ISO7816 communications stack on both SIM cards and smartcards, and to perform MITM attacks on these devices.