If a person want to install a phone spy system onto a mobile phone
then it is very easy at the moment. If the target phone is of a person
who trusts the person who wants to install the spyware then it becomes
even easier. This is because it is now possible to download a spyware
directly to the mobile phone from the internet without having to
download it onto a computer first for eventual installation. However if
it is found out that you betrayed the trust accorded to you then you
stand a chance of losing a lot!
Source:
Cell Phone Spy