A researcher of the University of Luxembourg has demonstrated a new class of attacks against mobile phones at the security conference DeepSec in Vienna recently. Using a base transceiver station (commonly available for about 1000 Euro), he showed how common programming errors in the communication stack of mobile phones can be exploited to gain control over the devices.

Ralf-Philipp Weinmann found devastating flaws in a large percentage of cellular communication stacks. According to him, sufficiently motivated attackers are able to perform these attacks, which are almost undetectable. They allow to take over control of mobile phones in the range of the rogue transceiver, which may mean hundreds of phones at a time in crowded urban areas. Attackers hence are able to cause billing problems by either dialling premium numbers or sending text messages to premium services — or monitor the complete communications of the cell phone user.

Moreover, even eavesdropping on the surroundings of the cell phone is possible by making the cell phone pick up incoming calls automatically — without the user noticing. The attacking transceiver needs to be online for just a couple of seconds to perform the attack.

The University of Luxembourg, an international university focusing on research areas like Security in Information Technology, is working together with a number of vendors for both cellular communication chips and mobile phones. The objective is to fix the security flaws found and to prevent similar flaws from happening in the future. While programming bugs are inevitable, serious code security audit and exploit mitigations by the major baseband chip vendors help to reduce this class of security problem.