First working prototypes of Osmocom SIMtrace design

Harald Welte

2011-06-22

Last winter I was working on some hardware and software that can be used to trace the communication between a SIM card and a phone and called it Osmocom SIMtrace. At that time, I was simply recycling an old OLIMEX development board for the AT91SAM7S micro-controller.

But since the firmware for the micro-controller, the host software as well as the wireshark plug-in has been written now, it would be a shame if I was they only user of the project. Therefore, Kevin Redon and I have spent some time in polishing and improving the design, as well as generate some actual prototypes.

Unfortunately a number of mistakes were made (both on the design side but also wrong component pin-outs) so there was a need for significant re-working.

Nonetheless, we now have some 5 functional prototypes, a picture can be seen in the Osmocom Wiki, where you can also find the schematics

We're now having a second version of the PCB built, this time hopefully with correct footprints for all parts. Once that is verified at the end of next week, we will give "go" for the production of a small batch (100 units).

Interested developers will be able to obtain the resulting hardware from mid-August onwards. We also expect to be offering them at the Radio Village of the 2011 CCC Camp.

Tracing the SIM<->Phone protocol can be useful in a variety of cases:

Observing the behavior of operator-issued SIM cards in terms of which SIM Application Toolkit or Proactive SIM features they use.
Debugging aid while developing and interoperability testing of your own SIM toolkit applets
Prototyping and development of SAT blocker or other SIM card firewalls which restrict the security or privacy threats originating from untrusted operator SIMs or potentially compromised SIM cards.