Percent symbol can disable Wi-Fi on iPhones says, Researcher
It seems that Wi-Fi networks with percent symbols in their names can cause an error.
A security researcher found that certain Wi-Fi networks with the percent symbol (%) in their names can disable Wi-Fi on iPhones and other iOS devices. Carl Schou tweeted that if an iPhone is within range of a network called% secretclub% power, the device will not be able to use Wi-Fi or any related functions, and even after resetting network settings, the error may continue to process Wi-Fi. -Fi on device unusable.
A few weeks ago, Schou and his nonprofit group Secret Club, which reverse-engineer software for research purposes, discovered that if an iPhone were connected to a network named SSiD% p% s% s% s% s% n would cause a bug in the iOS network stack that would disable your Wi-Fi, and system networking features like AirDrop would be unusable.
9to5 Mac offered a possible explanation for the strange error:
The syntax "% [character]" is commonly used in programming languages to format variables in an output string. For example, in C, the specifier "% n" means to store the number of characters written to the format string in a variable passed to the format string function. The Wi-Fi subsystem probably passes the Wi-Fi network name (SSID) without sanitizing to some internal library that is doing string formatting, which in turn causes arbitrary memory write and buffer overflow. This will lead to memory corruption, and the iOS watchdog will kill the process, thus effectively disabling Wi-Fi for the user.
The Verge reached out to Apple to see if they are working on a fix and will update if we hear from them. But as 9to5 Mac points out, the error can probably be avoided by not connecting to Wi-Fi networks with percent symbols in their names.