According to the researchers – Karsten Nohl and Sylvian Munaut – whilst the cracking technique is nothing new, the hardware previously required ran well into four (dollar) figures.
In fact, Infosecurity notes, one specialist kit costing around $1500 was shown at the Defcon IT security event last summer and caused something of a stir.
Giving a demonstration of the low-cost crack at the Chaos Computer Club conference taking place in Berlin last week, the researchers explained that the use of multiple handsets allows crackers to narrow down their search for a given handset to a small area of a city or rural area.
Then by generating text messages with 'broken headers', crackers can trigger a handset to load up software from the mobile internet without the user being aware of the message or its contents.
By using low-cost Motorola handsets loaded with specialist software, Nohl and his colleague were reportedly able to 'sniff' the network and its interactions with the target handset, and effectively eavesdrop on the 'conversation' taking place on the mobile concerned.
Reporting on the demonstration at the Chaos Computer Club conference, Stefan Krempl of the Heisse Online newswire, said that Nohl no longer supports the club's call – made last year – to completely revamp the encryption algorithm.
"He says it would take too long and be too expensive. In contrast, he says that a number of design flaws have been improved in UMTS, though the improvements will not really help as long as the latest generation of cell phones still often rely on GSM", said the newswire.