Millions of Sim cards are 'vulnerable to hack attack'

Karsten Nohl says one in eight
Sims might be vulnerable to attack.

A flaw with mobile phones' Sim card technology is putting millions of people at risk of being spied on and robbed, according to a leading security expert.

Karsten Nohl has said he has found a way to discover some Sims' digital keys by sending them a special text message.

He warned criminals could potentially use the technique to listen in on calls or steal cash.

Industry organisation - the GSMA - said it was looking into the findings.