Bug in iOS can break iPhone Wi-Fi using rogue hotspot name

Security researcher Carl Schou gave a personal Wi-Fi hotspot a name of "%p%s%s%s%s%n." On trying to connect to the hotspot, Schou discovered the iPhone simply couldn't connect to it at all, and later discovered that it disabled Wi-Fi connectivity completely on the device.

Attempts to connect to other hotspots failed, with the issue continuing to mainifest after changing the hotspot's SSID and rebooting the iPhone, according to BleepingComputer. The issue was also confirmed by others testing out the same SSID name separately.

Tests also point to it being a problem just with iPhones, as Android devices appear to connect to the unusually-named access point without issue.

Other researchers examining the phenomena believe it is an issue with input parsing, in that the percentage sign at the start may be misinterpreted by iOS as a string-format specifier, in that characters following may be a variable or a command rather than plain text.

To fix the problem on affected iPhones, users have to reset their iOS network settings.

How to reset network settings in iOS

• Open Settings
• Select General then Reset
• Select Reset Network Settings
• Confirm the request.
• Once the iPhone has restarted, set up your Wi-Fi as normal.

The discovery is reminiscent of text messages that contained strings and special characters that could cause problems for iPhones and iPads. For example, April's "text bomb" forced iPhones to crash if a flag emoji and a specific Sindhi language character were viewed in an incoming notification.

Keep up with everything Apple in the weekly AppleInsider Podcast — and get a fast news update from AppleInsider Daily. Just say, "Hey, Siri," to your HomePod mini and ask for these podcasts, and our latest HomeKit Insider episode too.

If you want an ad-free main AppleInsider Podcast experience, you can support the AppleInsider podcast by subscribing for $5 per month through Apple's Podcasts app, or via Patreon if you prefer any other podcast player.

AppleInsider is also bringing you the best Apple-related deals for Amazon Prime Day 2021. There are bargains before, during, and even after Prime Day on June 21 and 22 — with every deal at your fingertips throughout the event.