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

(Image credit: Future)

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

You won't exist able to connect to another hotspot, and rebooting the iDevice doesn't fix the problem. Just there is a style to go out of the hole without completely factory-resetting your iPhone or iPad.

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

After joining my personal WiFi with the SSID "%p%s%s%s%s%due north", my iPhone permanently disabled it's WiFi functionality. Neither rebooting nor changing SSID fixes it :~) pic.twitter.com/2eue90JFu3June 18, 2021

Encounter more than

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

Schou told Bleeping Computer that he had found this flaw on an iPhone XS running iOS 14.4.2. The website reproduced it on an iPhone running iOS xiv.vi, the nigh recently released version of Apple tree'due south mobile operating system. Android phones do not seem to be afflicted.

"In some tests, connecting to the SSID would fail, but we could no longer access our regular wireless network," wrote Bleeping Estimator's Ax Sharma. "Other tests led to the behavior described past Schou, where the iPhones Wi-Fi setting would be disabled, and we could no longer enable information technology over again."

Malicious actors could weaponize this flaw by setting upward hotspots in public places without passcodes, leading data-hungry iPhones and iPads with Wi-Fi turned on to attempt 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 get 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 easy solution was at mitt.

All you need to do is go into Settings, then select Full general, then go to Reset. Don't "Reset All Settings" or "Erase All Content and Settings." Instead, scroll down a bit and then tap "Reset Network Settings.

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

Dizzy strings

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

Bleeping Computer said that iOS seems to exist interpreting the "%north" cord in the SSID name every bit a command variable in the C programming language, rather than as but plain text.

"%p%southward%south%s%south%due north" 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 after format strings to f*** with poorly developed devices."

Paul Wagenseil is a senior editor at Tom'south Guide focused on security and privacy. He has also been a dishwasher, fry cook, long-haul commuter, code monkey and video editor. He's been rooting around in the information-security space for more than xv 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 Idiot box news spots and fifty-fifty moderated a panel discussion at the CEDIA home-technology conference. You can follow his rants on Twitter at @snd_wagenseil.