There is an apparently new iOS 18 security feature that reboots iPhones that haven’t been unlocked in a few days, frustrating police by making it harder to break into suspects’ iPhones, according to 404 Media.
After the mysterious reboots, the devices supposedly enter what is called the Before First Unlock (BFU) state. This makes cracking them to get data about criminal activity much harder.
The document seen by 404 Media theorized that the iPhones rebooted in “a short amount of time” when removed from a cellular network, potentially around 24 hours. According to the document, one of the iPhones was even in Airplane mode and one was inside what is called a Faraday box, a type of container that blocks electronic signals from reaching the iPhone, stopping them from accessing telecom coverage, as well as things like Bluetooth and Wi-Fi.
The police speculate that the mysterious reboot may have been because of “an iOS 18.0 security feature addition.” The document also theorizes that iPhones with iOS 18.0 brought into the lab communicated with the other iPhones, sending a signal to the phones to reboot.
However, Jiska Naehrdine, an independent cybersecurity researcher, claimed that Apple did introduce an “inactivity reboot” in iOS 18.1, citing code hosted on GitHub.
She commented on the design choice: “This is a cheap & great mitigation!”
“While most people won’t have their phone forensically analyzed, many more will have their devices stolen,” she added. “It protects user data in both cases.”
The company has steadily made iPhones harder to compromise over the years, putting it at odds with law enforcement and raising the specter of government regulations requiring encryption backdoors. Apple has repeatedly resisted authorities’ requests to create backdoors, although that hasn’t stopped law enforcement from finding its own workarounds.