iOS 18.3.1 Update Released With Fix for Critical, Actively Exploited USB Security Flaw

iOS 18.3.1 began rolling out to users on Monday, and the latest update for supported iPhone models arrives with an important patch for a critical security flaw. The vulnerability allowed some attackers to gain access to a user's iPhone, even while it was locked. Apple has also confirmed that the security flaw may have been exploited to target some individuals. Users with eligible iPhone models should update to the latest version of iOS, which includes a fix for the vulnerability.

iOS 18.3.1 Update Fixes USB Restricted Mode Vulnerability

Apple's release notes for the iOS 18.3.1 and iPadOS 18.3.1 update state that the company has fixed a vulnerability in the Accessibility service on its mobile and tablet operating systems. According to Apple, the security flaw would allow a physical attack on a locked device, which could be used to disable USB Restricted Mode.

The iPhone maker introduced USB Restricted Mode with iOS 11.4.1 in 2018, and the feature is designed to block all communication with a connected USB accessory. Users need to unlock their device to connect it to their accessory, which won't work if the device has not been unlocked within the past hour.

The latest release notes state that Apple is aware that the security flaw may have been used in an "extremely sophisticated attack against targeted individuals". It's worth noting that an attacker would need to have physical access to a user's device in order to gain access to the device.

Apple has credited Bill Marczak, a researcher at The Citizen Lab at The University of Toronto's Munk School with identifying the security flaw. Marczak has also urged users with eligible iPhone and iPad models to update to the latest iOS 18.3.1 update, which should include a fix for the vulnerability.

iOS 18.3.1 is available for the latest iPhone 16 series, as well as older models going back to the iPhone XS. iPhone and iPad users can launch the Settings app and tap on General > Software Update > Install Now in order to install the update.