Now-Fixed AirDrop Bug Let Anyone Lock-Up Nearby iPhones With Flood of Files

There was a serious AirDrop bug in iOS 13.2.3 that let attackers overwhelm nearby iPhones with files, causing them to lock up, reports TechCrunch. Apple addressed the bug in the iOS 13.3 update, and the details of how it works are now public.

AirDrop is designed to allow users to share files with one another, and depending on settings, it can be restricted to contacts, no one, or any nearby iPhone. Kishan Bagaria discovered the AirDrop bug in iOS 13.2.3, finding that he could lock up nearby iPhones that were able to accept files by flooding them with multiple files in a row.

When receiving an AirDrop file, an iPhone or iPad blocks the display until the incoming request is accepted or rejected. iOS did not limit the number of requests that a device can accept, so with repeated message requests, an attacker was able to send files over and over again to cause the iOS device to get stuck in a loop.

Devices with AirDrop set to "Everyone" were primarily vulnerable to the attack, which is not the default AirDrop setting. AirDrop is limited to Contacts, and the "Everyone" setting must be manually enabled.

As of now, though, the bug no longer works and Apple has limited the number of AirDrop messages that can be sent to an iOS device in quick succession. Given that this wasn't a traditional security vulnerability, Apple will not provide a common vulnerability and CVE score, but has instead acknowledged it in a separate section of the security support document.