Feeds

Israeli boffins crack GSM code

Phreak Like Me

  • alert
  • submit to reddit

The essential guide to IT transformation

A team of Israeli scientists have uncovered a possible means of cracking the GSM mobile phone network encryption code, opening the door to attacks that could enable eavesdroppers to listen into calls.

The GSM Association, a trade group for suppliers and mobile network operators, is downplaying the problem. It admits a potential vulnerability exists but argues that this would be very difficult to exploit in practice.

Researchers Professor Eli Biham and doctoral student Elad Barkan, and Nathan Keller, all of the Technion Institute in Haifa, discovered basic weaknesses in the encryption scheme used in GSM networks.

According to Biham, the attack allows an eavesdropper to tap into a conversation while a call is been set up and a phone at the receiver's end is still ringing. After this, a conversation can be overheard.

"Using a special device it's possible to steal calls and impersonate callers in the middle of a call as it's happening," Biham told Reuters.

The security loophole arises because of a fundamental mistake made by GSM developers in creating a system which corrected for interference of the line prior to encrypting a conversation, he explained.

The researchers have produced a paper, Instant Ciphertext-Only Cryptanalysis of GSM Encrypted Communication, documenting their findings. The paper was presented at last month's Crypto Conference in Santa Barbara, California but news of this alarming discovery only broke yesterday.

The GSM Association admits the Israeli researchers are onto something but say the attack requires the use of complex technology, which few phone phreakers have access to, and would need to be targeted at a specific caller.

According to Reuters, the Association claims an attacker would have to "transmit distinctive data over the air to masquerade as a GSM base station". An attacker would also have to be placed between a caller and a base station to intercept a call, it adds.

"This (technique) goes further than previous academic papers, (but) it is nothing new or surprising to the GSM community. The GSM Association believes that the practical implications of the paper are limited," it said in a statement.

The Association said an upgrade to the A5/2 encryption algorithm, available since July 2002, addresses the security weaknesses highlighted by the Israelis.

Biham disputes this and says the new encryption system, which was put in place in response to previous attacks, is itself vulnerable.

Both parties agree that the issue does not affect 3G phones, which use different protocols and security mechanisms than legacy GSM handsets. ®

External Links

GSM Security FAQ

Related Stories

Attack of the clones
SMS phone crash exploit a risk for older Nokias
Mobile security needs to change with GPRS
3G crypto a go-go
Captain Crunch sets up security firm

Next gen security for virtualised datacentres

More from The Register

next story
Ice cream headache as black hat hacks sack Dairy Queen
I scream, you scream, we all scream 'DATA BREACH'!
Goog says patch⁵⁰ your Chrome
64-bit browser loads cat vids FIFTEEN PERCENT faster!
NIST to sysadmins: clean up your SSH mess
Too many keys, too badly managed
Scratched PC-dispatch patch patched, hatched in batch rematch
Windows security update fixed after triggering blue screens (and screams) of death
Researchers camouflage haxxor traps with fake application traffic
Honeypots sweetened to resemble actual workloads, complete with 'secure' logins
Attack flogged through shiny-clicky social media buttons
66,000 users popped by malicious Flash fudging add-on
New Snowden leak: How NSA shared 850-billion-plus metadata records
'Federated search' spaffed info all over Five Eyes chums
Three quarters of South Korea popped in online gaming raids
Records used to plunder game items, sold off to low lifes
Oz fed police in PDF redaction SNAFU
Give us your metadata, we'll publish your data
prev story

Whitepapers

5 things you didn’t know about cloud backup
IT departments are embracing cloud backup, but there’s a lot you need to know before choosing a service provider. Learn all the critical things you need to know.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Backing up Big Data
Solving backup challenges and “protect everything from everywhere,” as we move into the era of big data management and the adoption of BYOD.
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.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?