Eavesdrop on encrypted GSM call: $15 phone and 180 seconds

[Sabre]

Wired article

BERLIN — Whatever assurances have been given about the security of GSM cellphone calls, forget about them now.

Speaking at the Chaos Computer Club (CCC) Congress here Tuesday, a pair of researchers demonstrated a start-to-finish means of eavesdropping on encrypted GSM cellphone calls and text messages, using only four sub-$15 telephones as network “sniffers,” a laptop computer and a variety of open source software.

While such capabilities have long been available to law enforcement with the resources to buy a powerful network-sniffing device for more than $50,000 (remember The Wire?), the pieced-together hack takes advantage of security flaws and shortcuts in the GSM network operators’ technology and operations to put the power within the reach of almost any motivated tech-savvy programmer.

“GSM is insecure, the more so as more is known about GSM,” said Security Research Labs researcher Karsten Nohl. “It’s pretty much like computers on the net in the 1990s, when people didn’t understand security well.”

Several of the individual pieces of this GSM hack have been displayed before. The ability to decrypt GSM’s 64-bit A5/1 encryption was demonstrated last year at this same event, for instance. However, network operators then responded that the difficulty of finding a specific phone, and of picking the correct encrypted radio signal out of the air, made the theoretical decryption danger minimal at best.

Naturally this sounded like a challenge.

[Mr Kleen]

Naturally this sounded like a challenge.

[complacent]

one year i'd really like to make it to a ccc.



cool stuff.