You can install ransomware on a Samsung Galaxy by sending it an SMS

https://www.youtube.com/watch?time_continue=1&v=hL3gA8IMO-w

Researchers from Context Security have identified a vulnerability in Samsung Galaxy phones: by embedding commands in the obsolete, 17-year-old WAP proptocol in an SMS message, attackers can put them into endless reboot loops, or encrypt their storage and charge the phone's owners for a decryption key. (more")