A web-based CSS iPhone hack has the ability to crash and restart your phone with just a few lines of code, exploiting weaknesses in WebKit (via TechCrunch).
CSS iPhone Hack
Security researcher Sabri Haddouche tweeted a proof-of-concept website. It has 15 lines of code, and if you visit it on your iPhone it will crash and restart. Visiting it on macOS could cause Safari to freeze.
TechCrunch tested the exploit running on the most recent mobile software iOS 11.4.1, and confirm it crashes and restarts the phone. Thomas Reed, director of Mac & Mobile at security firm Malwarebytes confirmed that the most recent iOS 12 beta also froze when tapping the link.
It takes advantage of a weakness in WebKit, a web rendering engine Apple uses for Safari. Mr. Haddouche says that nesting a bunch of CSS elements—like <div> tags—inside a backdrop filter category will use up all of the iPhone’s resources. It causes a kernel panic, which shuts the iPhone down and restarts it to prevent damage.