SIM or subscriber identity module is
essential in mobile communication, SIM is a microchip or an
electronic circuit that stores IMSI and other authentication and
identification code. The foremost objective of SIM is to give the
identification of its owner in the mobile communication network, it
also carries the network signals that can hacked to control a mobile
phone. How to hack into a SIM card is not the primary objective of
this article, however we will study the structure of a SIM and
exploitation process.

Abstract

SIM cards can do more than just authenticate your phone with your
carrier. Small apps can be installed and run directly on the SIM
separate from and without knowledge of the phone OS. Although SIM
Applications are common in many parts of the world, they are mostly
unknown in the U.S. and the closed nature of the ecosystem makes it
difficult for hobbyists to find information and experiment.

 This talk, based on our experience building SIM apps for the
Toorcamp GSM network, explains what (U)SIM Toolkit Applications are,
how they work, and how to develop them. We will explain the various
pieces of technology involved, including the Java Card standard,
which lets you write smart card applications using a subset of Java,
and the GlobalPlatform standard, which is used to load and manage
applications on a card. We will also talk about how these
applications can be silently loaded, updated, and interacted with
remotely over-the-air.

Presentation

Source, defcon 21