A security specialist has found that certain Wi-Fi networks with the percent symbol (%) in their names can disable Wi-Fi on iPhones and different iOS devices. Carl Schou tweeted that if an iPhone comes within range to an organization named %secretclub%power, the gadget will not have the option to utilize Wi-Fi or any related features, and surprisingly in the wake of resetting network settings, the bug may keep on delivering Wi-Fi on the device unusable.
Half a month prior, Schou and his not-profit group, Secret Club, which reverse-engineers software for research purposes, discovered that if an iPhone connected with an organization with the SSiD name %p%s%s%s%s%n it’s anything but a bug in iOS’ organizing stack that would handicap its Wi-Fi, and framework organizing highlights like AirDrop would get unusable.
They offered a possible explanation for the weird bug:
the ‘%[character]’ syntax is commonly used in programming languages to format variables into an output string. In C, the ‘%n’ specifier means to save the number of characters written into the format string out to a variable passed to the string format function. The Wi-Fi subsystem probably passes the Wi-Fi network name (SSID) unsanitized to some internal library that is performing string formatting, which in turn causes an arbitrary memory write and buffer overflow. This will lead to memory corruption and the iOS watchdog will kill the process, hence effectively disabling Wi-Fi for the user.
They have reached with Apple to check whether it’s working but’s a fix, and will refresh in the event that we hear back from them. Yet, as 9to5 Mac noticed, the bug can almost certainly be kept away from by not connecting with Wi-Fi networks with percent symbols in their names.