That assessment may sound extreme, but researchers Charlie Miller and Collin Mulliner said it's no joke. According to the two security experts, a vulnerability in the iPhone's SMS, or text-messaging, utility could be used to take control of the entire device.
Apple has released a security update for the hack at Apple.com.
The hack works like this: An attacker would send a series of invisible SMS messages to a device. Eventually, the attacker would have control of the device and the ability to dial numbers, take pictures, record sound or surf websites. In addition, the attacker could send out other malicious SMS bursts from a compromised phone to other phones.
"This is serious," Miller said. "The only thing you can do to prevent it is turn off your phone. Someone could pretty quickly take over every iPhone in the world with this."
Tech analyst Iria of Huliq.com dismissed that assessment, noting that in order for a hacker to take control of every iPhone in the world, the hacker would have to know enough phone numbers to do it. All the same, Iria conceded that the vulnerability was for real.
"It is obviously very serious, and despite the researchers sharing their results with Apple over a month ago, there has been no movement on a fix as of yet," Iria said.
Miller and Mulliner said that the only sign that a phone is under attack is a text message that displays a single, square character. If someone receives that message, they should turn off their iPhone.