Feeds

Cellphone snooping now easier and cheaper than ever

Breaking GSM for $650

Using blade systems to cut costs and sharpen efficiencies

Cryptographers have devised a low-cost way to intercept phone calls and text messages sent over the majority of the world's mobile networks.

The attack, which requires four $15 Motorola handsets, a medium-end computer and a 2TB hard drive, was demonstrated last week at the 27th annual Chaos Communication Congress in Berlin. It builds off of last year's crack of the A5/1 encryption algorithm used to protect communications sent using GSM, or Global System for Mobile Communications, technology, which carries an estimated 80 percent of the world's mobile traffic.

The method, cooked up by researchers Karsten Nohl and Sylvain Manaut, is a significant improvement over previous techniques, which required two USRP2 receivers and software to rapidly change radio frequencies over a spectrum of 80 channels. Equipment costs of the new attack are about $650, compared with more than $4,000 using the previous method.

“GSM is as insecure as Wi-Fi was ten years ago,” Nohl, who is chief scientist at Berlin-based Security Research Labs, told The Register. “It will be attacked by the same 'war-driving' script kiddies soon. Any discussion over whether the attacks available in the community are incomplete or impractical should have been put to rest with the last demonstration so that we can now start discussing how to fix the networks.”

Nohl, a cryptographer who has identified gaping holes in smart cards, cordless phones and car immobilizers designed to thwart auto thieves, was alluding to comments last year from the GSM Alliance, which claimed eavesdropping on GSM communications wasn't practical.

Nohl has long nudged mobile operators to adopt the significantly more secure A5/3 algorithm, which still isn't widely deployed – presumably because of the cost of upgrading a huge amount of equipment that's already in place. He also counsels them to take several “low-hanging fruit” measures. One fix involves restricting access to the HLR, or Home Location Register, which is the database that keeps track of a handset's location on a carrier's network. Another suggestion is for operators to randomize message padding when encrypting communications.

GSM is the most widely used mobile phone technology. It connects more than 5 billion phones, according to the GSMA. In the US, it's used by AT&T and T-Mobile. It's used by all major carriers in the UK.

The revised attack uses home-brewed firmware to turn the Motorola phones into wire-tapping devices that pull conversations and text messages off of a carrier's base station. They are connected to a PC that has access to a 2TB rainbow table used to decrypt messages protected by the decades-old A5/1 algorithm. H-online.com and Wired.com have more technical details here and here. Slides from the presentation are here. ®

The smart choice: opportunity from uncertainty

More from The Register

next story
Yorkshire cops fail to grasp principle behind BT Fon Wi-Fi network
'Prevent people that are passing by to hook up to your network', pleads plod
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
NEW, SINISTER web tracking tech fingerprints your computer by making it draw
Have you been on YouPorn lately, perhaps? White House website?
LibreSSL RNG bug fix: What's all the forking fuss about, ask devs
Blow to bit-spitter 'tis but a flesh wound, claim team
Black Hat anti-Tor talk smashed by lawyers' wrecking ball
Unmasking hidden users is too hot for Carnegie-Mellon
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Own a Cisco modem or wireless gateway? It might be owned by someone else, too
Remote code exec in HTTP server hands kit to bad guys
prev story

Whitepapers

Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.