Researchers Discover AirDrop Security Flaw That Could Expose Personal Data to Strangers
AirDrop is a feature that allows Apple devices to securely and conveniently transfer files, photos, and more between each other wirelessly. Users can share items with their own devices, friends, family, or even strangers. The convenience and ease of use, however, may be undermined by a newly discovered security flaw.

Researchers at TU Darmstadt have discovered that the process which AirDrop uses to find and verify someone is a contact on a receiver's phone can expose private information. AirDrop includes three modes; Receiving Off, Contacts Only, Everyone. The default setting is Contacts Only, which means only people within your address book can AirDrop photos, files, and more to your device.
The researchers discovered that the mutual authentication mechanism that confirms both the receiver and sender are on each other's address book could be used to expose private information. The researchers claim that a stranger can use the mechanism and its process within the range of an iOS or macOS device with the share panel open to obtain private information. As the researchers explain:
As an attacker, it is possible to learn the phone numbers and email addresses of AirDrop users – even as a complete stranger. All they require is a Wi-Fi-capable device and physical proximity to a target that initiates the discovery process by opening the sharing pane on an iOS or macOS device.
The discovered problems are rooted in Apple's use of hash functions for "obfuscating" the exchanged phone numbers and email addresses during the discovery process. However, researchers from TU Darmstadt already showed that hashing fails to provide privacy-preserving contact discovery as so-called hash values can be quickly reversed using simple techniques such as brute-force attacks.
To determine whether the other party is a contact, AirDrop uses a mutual authentication mechanism that compares a user's phone number and email address with entries in the other user's address book.
According to the researchers, Apple was informed of the flaw in May of 2019, and despite several software updates since then, the flaw remains.
Related Stories
Last week, security researcher Denis Tokarev made several zero-day iOS vulnerabilities public after he said that Apple had ignored his reports and had failed to fix the issues for several months.
Tokarev today told Motherboard that Apple got in touch after he went public with his complaints and after they saw significant media attention. In an email, Apple apologized for the contact delay...
A group of UK network operators have formally urged the UK's Competition and Markets Authority (CMA) to regulate iCloud Private Relay, claiming that Apple's privacy service is anti-competitive, potentially bad for users, and a threat to national security.
In its response to the CMA's Interim Report on mobile ecosystems, Mobile UK, a trade association of British mobile network operators,...
Apple is streamlining its iPhone purchase process with the launch of the iPhone SE, and has introduced a new buying method that allows customers to purchase T-Mobile and AT&T devices without inputting their current carrier information.
As outlined by Bloomberg, customers typically need to provide their wireless phone number and social security number when making an iPhone purchase, a process ...
watchOS 8.5 fixes a security vulnerability in the Mail app that could leak a user's IP address when downloading remote content, security researchers have found.
Last year, it emerged that Apple's Mail Privacy Protection feature was undermined by a lack of Apple Watch support. Mail Privacy Protection was a new feature introduced with iOS 15, iPadOS 15, and macOS Monterey that hides your IP...
In 2019, Apple opened its Security Bounty Program to the public, offering payouts up to $1 million to researchers who share critical iOS, iPadOS, macOS, tvOS, or watchOS security vulnerabilities with Apple, including the techniques used to exploit them. The program is designed to help Apple keep its software platforms as safe as possible.
In the time since, reports have surfaced indicating...
The security provided by Apple's Mail Privacy Protection feature is seemingly undermined by a lack of Apple Watch support, security researchers have found.
Mail Privacy Protection is a new feature introduced with iOS 15, iPadOS 15, and macOS Monterey that hides your IP address so senders are not able to determine your location or link email habits to your other online activity. It also...
Wednesday December 29, 2021 10:15 am PST by
Juli CloverBack in August, T-Mobile suffered a massive data breach impacting more than 50 million current, former, and prospective T-Mobile users, and now the cellular company is dealing with another smaller data breach incident.
Reports yesterday suggested that T-Mobile was aware of unauthorized activity affecting some customer accounts, and now, T-Mobile has confirmed that those reports were due to...
T-Mobile has not disabled iCloud Private Relay for its subscribers, in contrast to recent reports suggesting the carrier was preventing iPhone users from enabling the feature.
In a statement to Bloomberg's Mark Gurman, T-Mobile said that iOS 15.2 device settings that default to the feature being toggled off, and that Apple has been contacted. T-Mobile explicitly says that iCloud relay has...
Popular Stories
Earlier today, analyst Ming-Chi Kuo claimed iPhone 14 Pro models will be more expensive than iPhone 13 Pro models. Kuo did not reveal exact pricing, but he said that the average selling price of all four iPhone 14 models will increase by about 15% overall.
While higher prices would be disappointing for customers, it is possible the iPhone 14 Pro and iPhone 14 Pro Max will offer increased...
Apple this week brought back one of the most highly requested features from iOS users since the launch of the iPhone X in 2017: the ability to see your battery percentage directly in the status bar.
Ever since the launch of the iPhone X with the notch, Apple has not allowed users to show their battery percentage directly in the status bar, forcing them to swipe down into Control Center to...
Apple plans to increase the prices of iPhone 14 Pro models compared to iPhone 13 Pro models, according to analyst Ming-Chi Kuo.
Kuo did not reveal exact pricing for the iPhone 14 Pro models. However, in a tweet today, he estimated that the average selling price of the iPhone 14 lineup as a whole will increase by about 15% compared to the iPhone 13 lineup.
In the United States, the iPhone...
With the fifth beta of iOS 16, Apple has updated the battery icon on iPhones with Face ID to display the specific battery percentage rather than just a visual representation of battery level. The new battery indicator is available on iPhone 12 and iPhone 13 models, with the exception of the 5.4-inch iPhone 12/13 mini. It is also available on the iPhone 11 Pro and Pro Max, XS and XS Max, and...
In the latest iOS 16 beta, Apple has updated the status bar battery icon on iPhones with Face ID to display the exact percentage remaining rather than just a visual representation of battery level, and while the change has been largely welcomed, some users are unhappy with the way it has been implemented.
In iOS 15 and earlier, battery percent has not been present on iPhones that have...
Wednesday August 10, 2022 4:08 am PDT by
Sami FathiThe launch of the new iPhone 14 is just a few weeks away, meaning millions of iPhone customers will soon upgrade their existing iPhone or perhaps get an iPhone for the first time. Exclusive MacRumors iPhone 14 Pro renders by graphic designer Ian Zelbo Whether upgrading from an older model or this is your first iPhone, we've rounded up a few tips to help you prepare for the next flagship...
The iPhone 14 and iPhone 14 Pro models are rumored to be available in a refreshed range of color options, including an all-new purple color. Most expectations about the iPhone 14 lineup's color options come from an unverified post on Chinese social media site Weibo earlier this year.
Overall, the iPhone 14 and iPhone 14 Pro's selection of color options could look fairly similar to those of the ...
Top Rated Comments
AirDrop allows TWO different users logged into TWO devices under their own control to share data. Hence the need for authentication.
And the attack vector is super specific... a black hat *physically nearby* has to try to grab your data while you initiate the AirDrops (and I would guess most AirDrops are small things: a contact card, a photo, a doc... all which take seconds to transfer), and THEN brute force the hashes... for what? A bit of stolen PII?
Yes, it’s *possible* for someone to do this... but *probable*? Naahh. Which is why Apple hasn’t prioritized it. In risk management you have to prioritize the risks by probability and impact... this one is pretty low on both counts.
I do think the odds of someone brute forcing an airdrop in close
proximity to you in order to discover your phone number and email is pretty remote. One assumes that if they are going to all that effort to target you, they already know your name.
One question for the researchers: does this mean turning on “everyone” is more secure as no matching is attempted?