The stuff of nightmares is no longer the boogeyman or Bloody Mary--it’s mutated into hackers, thieves and crooks. An article from theguardian shows how a known hack dated back to 2014 is still very much in motion.
All they need is your phone number, and nothing else.
Regardless of carrier, with no remedy besides turning your phone off, this hack uses Signaling System No. 7 (SS7), a network interchange service, which “acts as a broker between mobile phone networks.”