Last night, I thought I heard an SMS tone from my phone. I ignored it since:
- Do Not Disturb was on
- The screen light didn't come on
This morning, my phone looked weird. There was a message on the screen, instantly recognisable as spam. But the message wasn't like a normal SMS. The rest of the screen was black, and the bottom only had a green "Dismiss" button. It looked like those carrier alerts: there is a new update for your phone. Was my carrier hacked? After some searching, I found out it was a "flash SMS". Characteristics of flash SMS:
- displays differently from normal SMS
- does not save, can only be dismissed
- (on iPhone) originating number not displayed
Currently, I can't find any way to send them without jailbreaking your iPhone.
It's rather disturbing that anybody can send these SMS. If you search, it's very easy to send an official-looking SMS that says your phone's been hacked, etc. Fortunately mine was clearly spam, so I wasn't worried. I think the main problem is iPhone doesn't display the sender, so you think it's from the system. Hopefully if this spam becomes more common, the next iOS update will show the sender.