Researcher finds sure community names can disable Wi-Fi on iPhones

A safety researcher has discovered that sure Wi-Fi networks with the p.c image (%) of their names can disable Wi-Fi on iPhones and different iOS units. Carl Schou tweeted that if an iPhone comes inside vary of a community named %secretclubpercentpower, the system received’t be capable of use Wi-Fi or any associated options, and even after resetting community settings, the bug could proceed to render Wi-Fi on the system unusable.

A couple of weeks in the past, Schou and his not-for-profit group, Secret Club, which reverse-engineers software program for analysis functions, found that if an iPhone connected to a community with the SSiD title %ppercentspercentspercentspercentspercentn it will trigger a bug in iOS’ networking stack that will disable its Wi-Fi, and system networking options like AirDrop would turn into unusable.

9to5 Mac offered a attainable rationalization for the bizarre bug:

the ‘%[character]’ syntax is often utilized in programming languages to format variables into an output string. In C, the ‘%n’ specifier means to avoid wasting the variety of characters written into the format string out to a variable handed to the string format operate. The Wi-Fi subsystem in all probability passes the Wi-Fi community title (SSID) unsanitized to some inside library that’s performing string formatting, which in flip causes an arbitrary reminiscence write and buffer overflow. This will result in reminiscence corruption and the iOS watchdog will kill the method, therefore successfully disabling Wi-Fi for the person.

We’ve reached out to Apple to see if it’s engaged on a repair, and can replace if we hear again from them. But as 9to5 Mac notes, the bug can doubtless be averted by not connecting to Wi-Fi networks with p.c symbols of their names.