Cell Phones Vulnerable To 'SMS Of Death'

Top 10 Security Stories Of 2010

Low-end mobile phones can be sent an "SMS-of-Death" to shut them down, knock them off of a cellular network, or even turn them into a brick.

So said researchers in a presentation at the recent 27th Chaos Communication Congress, a computer security conference in Berlin. Feature phones from such manufacturers as Nokia, LG, Samsung, Motorola, Sony Ericsson, and Micromax are vulnerable.

In their presentation, the researchers -- Collin Mulliner and Nico Golde, respectively a PhD student and undergraduate at the Technical University of Berlin -- detailed techniques for attacking feature phones "on a large scale" via short message service (SMS). "The attacks range from interrupting phone calls, to disconnecting people from the network, and sometimes even bricking phones remotely," they said. Vulnerable phones are offered by all of the world's major carriers.

Smartphones may be all the rage these days -- typically running iOS, Android, BlackBerry, Symbian, or Windows Phone 7 operating systems -- but only about one in six of the world's mobile phones are actually smartphones.

The rest are what are known as feature phones. According to Web site Know Your Mobile, "feature phones predominantly run on a proprietary Java ME platform and can, for this reason, only run basic applications -- hence why they're called 'feature' and not 'smart' phones."

Network operators often use SMS messages to remotely update feature phones. Mulliner and Golde took a similar approach, but used it to distribute malicious binaries. They also warned that a major attack developer would need to create just a handful of SMS messages -- one for each of the world's most popular handsets. Using inexpensive, mass-mailing SMS services, attackers could quickly and easily execute the attack on a wide scale.

According to MIT's Technology Review, Mulliner said that network operators are the only organizations able to defend against these types of attacks, either by updating phone firmware to block malicious binaries, or else by intercepting malicious SMS messages -- as is now done with spam -- before they're allowed to reach handsets.

According to the Technology Review, "Mulliner and Golde say they contacted network operators and manufacturers months before their talk but were told it wasn't possible to get fixes ready in time."