Skip to main content

That strangely named Wi-Fi hotspot could brick your iPhone, temporarily

Stofa wifi 1000/1000 mbt
(Image credit: stofa)
Audio player loading…

A security researcher has found that a crafted network name triggers a bug in iOS and completely disables an iPhone (opens in new tab)’s ability to connect to Wi-Fi (opens in new tab)

The bug was discovered by Carl Schou (opens in new tab), who explained that as soon as he joined a personal network named “%p%s%s%s%s%n”, his iPhone permanently disabled its Wi-Fi functionality. 

“Neither rebooting nor changing SSID fixes it,” wrote Schou, without going into details about how he discovered the bug.

According to 9to5Mac (opens in new tab), the bug also affects other iOS devices such as iPads (opens in new tab) and even disrupts networking features like AirDrop (opens in new tab)

Don’t connect to strangers

Luckily, connecting to the strangely named network doesn’t seem to cause permanent damage to the iOS devices and can be fixed without a trip to AppleCare (opens in new tab).

Just head into the Settings and reset all network settings, which will erase details about all the saved Wi-Fi networks including the one that triggered the bug. 

Apple is yet to officially acknowledge the bug, and it isn’t yet known which iOS releases are impacted by the bug, although it’s best to err on the side of caution and assume it exists in all iOS releases.

Bleeping Computer suggests (opens in new tab) that other security researchers believe the bug is an input parsing issue that makes iOS think the characters following the percent sign are a string format specifier, leading the iOS’ networking stack to misbehave. 

While the bug doesn’t appear to cause any permanent damage, we’d suggest users to stay away from connecting to any strangely named networks, which is never a good idea in the first place. 

With almost two decades of writing and reporting on Linux, Mayank Sharma would like everyone to think he’s TechRadar Pro’s expert on the topic. Of course, he’s just as interested in other computing topics, particularly cybersecurity, cloud, containers, and coding.