Archive for December 2009

26C3 - A Picture is Worth a Thousand Words

Dec 31, 2009


GSM Encryption (or the Lack Thereof)

Dec 31, 2009

At 26C3 there were a couple of pretty interesting talks dealing with GSM security and how it can be easily broken through active (IMSI catching) and passive (rainbow table attacks on the A5/1 cipher) attacks.

Now, researcher’s are pushing to phase out GSM’s A5/1 cipher replacing it with modern, non-proprietary cryptography as countermeasure to the weaknesses facilitating A5/1’s susceptibility to passive eavesdropping. While this is certainly not a bad idea, it will end up with all but secure GSM calls considering that for GSM calls only the wireless interface benefits from the encryption. It will prevent John Doe from listening to your GSM calls using a wiretapping device placed in front of your apartment, but by no means will it lead to end-to-end security for GSM calls.

So, instead of attacking the wireless interface a malicious hacker would have to turn to the (fixed) telephone network to get hold of your calls.

In the end, only end-to-end encryption of calls will be able to prevent such attacks, so this is IMHO what we should be striving for in the long run.

Zurück in die Steinzeit versetzt...

Dec 25, 2009

…wähnt man sich, wenn so elementare Dinge wie GSM nicht mehr funktionieren. So seit gestern in Heidelberg der Fall, wo nach meiner unmaßgeblichen Meinung die E-Plus-Basisstation in der Humboldtstraße ausgefallen sein dürfte. Mal schauen, wie lange Simyo (mein Vertragspartner) bzw. E-Plus brauchen, um das Problem zu beheben. Ich hoffe allerdings, dass sie nicht erst einen Techniker aus China einfliegen müssen. ;-)

Transferring Text Messages (SMS) from Nokia to Android

Dec 25, 2009

Around a month ago I replaced my old Nokia 6300 cell phone with the Android-based Motorola Milestone (aka. Motorola Droid). While I could easily transfer all contacts by adding them to my GMail contacts list the text messages (aka. SMS) were stuck on the old phone without any official way to transfer them to the Milestone. Fortunately, there is a solution using Gammu, some Perl scripting and the Android SMS Backup & Restore application.

Lieber rnv, ...

Dec 21, 2009

…es ist ja prima, dass ihr vor einiger Zeit den Fahrkartenverkauf in den Heidelberger Straßenbahnen abgeschafft habt und dafür an fast allen Haltestellen Fahrkartenautomaten aufgestellt habt. Es wäre jedoch hilfreich, wenn diese mindestens eine Zahlungsart akzeptieren würden und ich nicht beim Kauf eines Fahrscheins mittels gut getarnter Icons am Bildschirmrand mitgeteilt bekäme, dass der Automat heute leider weder Münzgeld, Scheine oder Kartenzahlung akzeptiert.

Reducing CO2 Emissions

Dec 20, 2009

<irony>Good news everyone, we have located the main contributor to climate change.</irony>

Running Asterisk on a FRITZ!Box 7270

Dec 20, 2009

Around a week ago I started experimenting with running Asterisk on my FRITZ!Box 7270 to replace my DECT phone, which has been getting a bit long in the tooth, with a SIP client running on my new Motorola Milestone HTC Desire cell phone so that when I am at home and my cell phone is signed in to my WLAN I can use it as a mobile handset for calls arriving on my landline.

As it turned out it is a little bit tricky to get Asterisk to compile for the FRITZ!Box, so this posting is supposed to summarize the steps I had to take and also comes with a neat helper script, which should automate most of the required preparation and compilation steps.