Karsten Nohl, who runs Security Research Labs in Germany, told the Reuters news agency that while hackers have been able to stage such attacks on a small scale, he believes multiple phones powered by GSM technology could be compromised at the same time.
“We can do it to hundreds of thousands of phones in a short time frame,” he told Reuters.
Roughly 80 percent of world mobile phone users, including practically everyone in Germany, use GSM networks. Mass attacks against phones in the networks could be particularly insidious because users wouldn't realize their phones had been compromised until they received their monthly bill.
Nohl is set to present his findings at a Chaos Computer Club conference on Tuesday, although he will not be providing technological details.
He told Reuters that not all wireless providers are equally secure. Germany's T-Mobile offers decent protection against hacking attacks, but other providers are much weaker, he said.
In any event, no wireless provider provides 100 percent protection against hackers, although many could improve their security simply by updating their software, he said.
“None of the networks protects users very well,” Nohl told Reuters.