Hackers work out how to block calls and texts nearby via feature phones

Anyone within 75 miles and on the same network as the hack are vulnerable

Researchers in Berlin have worked out a hack that can block calls and text messages for nearby people connected to the same cellular network, using just a Motorola C1 series phone

The security researchers, based at the Technical University of Berlin, presented a paper last week outlining the technique that blocks calls and texts.

With just a few modifications certain phones in the surrounding area can experience a 'jam' on their phone meaning no incoming calls or texts will be delivered.

The hack, using an open-source baseband code to write replacement software for Motorola's popular C1 series of phones, can affect anyone within a 75 mile radius on the same cellular network.

In a report by the MIT Technology Review, it is explained that the method operates on the second-generation (2G) GSM networks, the most commonly used network worldwide.

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For example, AT&T and T-Mobile in the US both carry calls and texts over GSM networks.

Researcher Nico Golde says "If you respond faster to the network, the network tries to establish a service with you as an attack."

Uusually a cellular tower will pick up the text/call signal and 'page' nearby devices to figure out which one is meant to receive it.

The rewritten firmware integrated into the hacking feature phone will then act faster then the cellular tower, blocking the signal.

MIT Tech Review states, "The group didn't design the hack to actually listen to the call or SMS but just hijacked the paging process."

Watch the hack in action below.

Source: MIT Technology Review