Rebirth of Scanning?

Some time ago Mike, G0VYN introduced me to a series of podcasts called Security Now. These are normally a bit too geeky, even for CARC, for me to pass comments on them in this forum! However episode 213 is of particular interest.

In amongst the general discussion of security issues in IT, this weeks issue deals with the hacking into GSM phone conversations. The GSM organization claim that this is not possible, but the podcast describes some very plausible ways that are open to the committed scanning enthusiast.

The core of the approach is to receive the phone signals on a Universal Software Radio Peripheral (USRP). The USRP and USRP2 work with GNU Radio, a free-software (open source) framework for the creation of software defined radios.

The podcast then describes weakness in the encryption of GSM phone transmissions, and how they can be exploited using a technique called rainbow tables in which most of the information needed to decipher the conversation is pre-computed and stored in a 2GB table. They then point at an open project similar to SETI that is aiming to compile the 2GB table and put it in the public domain.

There is also some material on how insecure supposedly high grade secure phones are and a note that 3G phones and a bit better than GSM, but not much better than GSM.

The podcast is available as audio (or in lower quality audio), and there are extensive show notes. It is well worth listening to from the perspective of a radio technologist.

Now of course it is not legal to listen to traffic that you are on licensed to receive, and I am neither personally interested in this traffic nor do I condone the activity (TM). However I do wonder how long it will be before the scanning enthusiasts are back in business.

Stewart/G3YSX