Call 911 if you want help.
Call 911 a hundred thousand times simultaneously from iPhones around the country if you want to jam up the 911 system.
Until recently, a design in the iPhone operating system allowed for just that kind of attack. But no more, thanks to an update in the latest iOS, version 10.3.
The Wall Street Journal reports that malicious code allegedly created by a nefarious Arizona teen and shared widely on Twitter forced iPhones to dial 911 over and over again — essentially DDoSing emergency call centers around the country.