German security expert Karsten Nohl demonstrated the hack by tracking a brand new phone given to US congressman Ted Lieu using only its phone number. Photograph: Alamy Hackers have again demonstrated that no matter how many security precautions someone takes, all a hacker needs to track their location and snoop on their phone calls and texts is their phone number. The hack, first demonstrated by German security researcher Karsten Nohl in 2014 at a hacker convention in Hamburg
