How does Pegasus spy on its targets?

The allegations that spy software known as Pegasus may have been used to carry out surveillance on journalists, activists - and even perhaps political leaders - highlights that surveillance is now for sale, BBC reports

Pegasus was built by Israeli firm NSO and the spyware can see everything stored in your phone. Finding out who your contacts were and how you lived your life would take patience and time.

Now, almost everything they might want to know - what you say, where you have been, who you meet, even what interests you - is all contained in a device we carry all the time. Your phone can be accessed remotely without anyone even touching it and you never knowing that it's been turned from your friendly digital assistant into someone else's spy, reports BBC's security correspondent Gordon Corera.