This iPhone bug kills your phone's Wi-Fi — what you need to know

This iPhone bug kills your telephone's Wi-Fi — what you need to know

(Image credit: Future)

Await out — there's a new iOS bug that can kill your iPhone or iPad'south Wi-Fi functions if you connect to a hotspot with a very unusual proper name, or SSID.

You lot won't exist able to connect to some other hotspot, and rebooting the iDevice doesn't gear up the problem. But there is a manner to become out of the pigsty without completely manufacturing plant-resetting your iPhone or iPad.

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"Later joining my personal WiFi with the SSID "%p%s%south%s%due south%n", my iPhone permanently disabled its WiFi functionality," wrote Danish hacker Carl Schou on Twitter on Friday (June 18). "Neither rebooting nor changing SSID fixes it :~)"

After joining my personal WiFi with the SSID "%p%s%s%due south%s%north", my iPhone permanently disabled it'due south WiFi functionality. Neither rebooting nor changing SSID fixes it :~) picture show.twitter.com/2eue90JFu3June xviii, 2021

When Schou tried to turn Wi-Fi back on again manually, the iPhone switched it off immediately.

Schou told Bleeping Calculator that he had plant this flaw on an iPhone XS running iOS 14.4.ii. The website reproduced it on an iPhone running iOS 14.6, the most recently released version of Apple's mobile operating arrangement. Android phones do not seem to be affected.

"In some tests, connecting to the SSID would fail, only we could no longer access our regular wireless network," wrote Bleeping Computer'southward Ax Sharma. "Other tests led to the behavior described by Schou, where the iPhones Wi-Fi setting would be disabled, and nosotros could no longer enable it over again."

Malicious actors could weaponize this flaw by setting up hotspots in public places without passcodes, leading data-hungry iPhones and iPads with Wi-Fi turned on to try to connect to information technology. Connecting to the hotspots would kill the Wi-Fi functions until the user took steps to fix it.

How to go your Wi-Fi back

Schou was at a loss on how to regain Wi-Fi functionality on his iPhone without having to factory-reset the whole thing, simply fortunately another Twitter users showed him that an like shooting fish in a barrel solution was at hand.

All you lot need to do is get into Settings, and then select General, then go to Reset. Don't "Reset All Settings" or "Erase All Content and Settings." Instead, roll downwards a bit and and then tap "Reset Network Settings.

Your iPhone or iPad will then reboot commonly, and you'll exist able to reconnect to other Wi-Fi hotspots, though you may have to enter in the hotspot passwords manually.

Silly strings

Chinese iPhone hacker ChiChou, aka CodeColorist, put up a blog post that dissected the flaw and explained that it's a format-string problems, something that is "rarely seen nowadays."

Bleeping Computer said that iOS seems to be interpreting the "%north" string in the SSID proper noun as a control variable in the C programming language, rather than equally merely apparently text.

"%p%s%s%s%south%n" is not an ordinary Wi-Fi network proper noun, to say the to the lowest degree. Schou told Bleeping Computer that "all my devices are named subsequently format strings to f*** with poorly developed devices."

Paul Wagenseil is a senior editor at Tom'southward Guide focused on security and privacy. He has too been a dishwasher, fry cook, long-haul driver, code monkey and video editor. He'southward been rooting around in the information-security space for more than 15 years at FoxNews.com, SecurityNewsDaily, TechNewsDaily and Tom's Guide, has presented talks at the ShmooCon, DerbyCon and BSides Las Vegas hacker conferences, shown up in random TV news spots and fifty-fifty moderated a panel word at the CEDIA home-technology conference. You can follow his rants on Twitter at @snd_wagenseil.