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blosxom


Contact/Impressum

       
Sun, 07 Nov 2010
Hashdays 2010 in Lucerne, Switzerland

The last couple of days I've been at #days 2010 in Lucerne / Switzerland. It was the first incarnation of this new IT security conference.

The conference went great, and I think the close-to-200 attendees were a great turnout for the first incarnation of an event. The talks were excellent, as was the delicious food that was served by the Radisson Blu hotel.

The GSM security workshop that David, Karsten and myself held over Wednesday and Thursday was attended by only 7 people, but we had some very lively discussions, particularly with some folks who were working for a GSM operator :)

Most notable about the event is the electronic conference badge, which was developed and produced with a lot of enthusiasm and numerous hours. To be honest, I think I would not have spent that much time on creating this. I mean, developing this type of gimmick is interesting, but then actually manually manufacturing it, without using a SMT line of any sorts - I wouldn't have done that 'just' for a badge. Respects to the team behind that. Hopefully the source code will still get released.

We were also running an experimental GSM + GPRS/EDGE network based on OpenBSC, OsmoSGSN and OpenGGSN, enabling users to run port scans and the like against the carrier-facing side of the IP stack of their own devices. While running this network, I discovered a number of new bugs, mostly in the GPRS stacks of various handsets.

At least one model of Blackberry seems to ignore the MS identity cannot be derived from the network cause of a Routing Area Update Reject message, which we send in case the TLLI of the messages from the phone is unknown. I would expect it to come back with a GPRS Attach Request, but it never does. All it does is to keep re-trying Routing Area Update

The other funny observation is: Several phones, including some iPhone models, react in a strange way if you REJECT them from the GSM network but ACCEPT them on GPRS (Assuming Network Mode of Operation III). They then seem to be perfectly happy with this connection, but will only supply data services and no voice service.

Getting back to the conference, though: The Radisson Blu is an quite costly, upscale hotel. I was really surprised by the type and number of small mistakes they made, particularly with the catering. One day they forget to put the sour cream next to the potatoes - despite a written sign indicating that they are supposed to be with sour cream. Another day they serve some mousse as desert, but there are no spoons placed at the desert buffet. Furthermore, the number of tables they provided during lunch time was always insufficient for the number of people who had lunch. The quantity of food was more than sufficient, though - indicating that it was not a problem of them not knowing the number of people who were eating.

[ /linux/conferences | permanent link ]

All your baseband are belong to us

I'd like to point out the slides of the talk: All Your Baseband Are Belong To Us by Ralf-Philipp Weinmann.

Ralf is one of those few people on this planet who have understood the security implications of now being able to send arbitrary protocol frames (particularly GSM L3 04.08 frames) to mobile phones.

GSM protocol stacks have never been written with the assumption that somebody might send intentionally malformatted messages on the air interface. But at the same time, the GSM network does not authenticate itself to the phone, i.e. everyone who can present a network-side GSM air interface to a phone will be able to exchange arbitrary messages with the phones.

This problem has been outlined in all the GSM security workshops and presentations I have been giving during recent years. Still, apart from Ralf-Philipp Weinmann's work, I have not seen a lot of public research in that area.

Exploiting and owning the baseband processor is a dangerous threat, as the microphone and entire audio path are connected to that very processor. Whoever owns the baseband can turn the mobile phone into a passive surveillance device, commonly called 'bug'. Since application processor and baseband processor are very far apart these days, with various layers of software in between, the user interface will not show any indication of what the baseband processor does.

[ /gsm | permanent link ]