A new threat has emerged for GSM networks, with two security researchers claiming that, for the first time, any GSM network or phone could be vulnerable to hackers, without the need to buy expensive network-sniffing tools.

There have been many attempts to demonstrate security flaws in GSM but Karsten Nohl and Sylvain Munaut claimed that they have built a toolkit that can hack into any network. The pair have demonstrated their work at the Chaos Computer Club Congress (CCC) in Berlin.

In the demo, the two researchers showed all the steps from locating a particular handset and capturing its ID, all the way to getting hold of data swapped between a phone and a cellular base station. The pair used Kraken, open source software on handsets.

In an interview with BBC News, Nohl said "Now there's a path from your telephone number to me finding you and listening to your calls".