Just a few weeks ago, security researcher Carl Schou discovered an iPhone WiFi bug that effectively disables an iPhone’s ability to connect to WiFi. Now that same researcher has discovered another naming scheme that does the same thing.
Schou on Sunday tweeted that if an iPhone comes in range of a WiFi network named ‘%secretclub%power’, then that iPhone will no longer be able to use WiFi or WiFi-related features. Schuo even says that this bug persists when resetting network settings.
— Carl Schou (@vm_call) July 4, 2021
We’re taking Schou’s word for this and didn’t test this latest revelation. MacTrast recommends that you do not try it either.
Schou’s earlier discovery relied on the iPhone connecting to a WiFi network with the name “%p%s%s%s%s%n” after which Schou’s iPhone’s Wi-Fi functionality was left “permanently disabled.” However, it turned out that the bug was fixable by resetting iPhone network settings in the Settings app.
This new issue appears more severe as it can trigger as soon as the iPhone comes in range of a malicious public Wi-Fi hotspot using that poisoned name. Both ‘%secretclub%power’ and ‘%p%s%s%s%s%n’ exploit a string format coding error somewhere in the underlying iOS networking stack.
At this point, it appears that network names using ‘%s’, ‘%p’ and ‘%n’ character sequences can trigger the issue. It is strongly recommended that users avoid connecting to Wi-Fi networks that contain percent symbols in their name. Apple will likely soon fix the issue in an OS update.