Disk Utility Bug in macOS High Sierra Exposes Passwords of Encrypted APFS Volumes in Plain Text [Updated]

Brazilian software developer Matheus Mariano appears to have discovered a significant Disk Utility bug that exposes the passwords of encrypted Apple File System volumes in plain text on macOS High Sierra.

disk utility password prompt

MacRumors confirmed our test password "dontdisplaythis" appeared as the hint

Mariano added a new encrypted APFS volume to a container, set a password and hint, and unmounted and remounted the container in order to force a password prompt for demonstration purposes. Then, he clicked the "Show Hint" button, which revealed the full password in plain text rather than the hint.

A second video with English system language is embedded below

MacRumors reproduced this behavior on a 2016 MacBook Pro running macOS High Sierra, including versions 10.13 and 10.13.1 beta. German software developer Felix Schwarz also shared a video of the issue on Twitter today.
The issue currently only affects Macs with SSD storage due to Apple File System compatibility, but APFS will eventually support machines with Fusion Drives as well. Schwarz believes users who haven't specified a password hint, or haven't used Disk Utility whatsoever, are probably not affected.

For clarity, this appears to be a bug within Disk Utility itself. When creating an encrypted APFS volume in Terminal with the diskutil command line utility, the actual hint is shown, rather than the password.

Mariano said he has reported the vulnerability to Apple. The company did not immediately respond to our request for a comment on the matter, but we'll update this article if we hear back.

Update: Apple has addressed this bug by releasing a macOS High Sierra 10.13 Supplemental Update, available from the Updates tab in the Mac App Store. Apple has also shared a support document outlining steps to back up, erase, and restore the encrypted APFS volume upon updating.

The bug has also been fixed in the base version of macOS High Sierra for those who have yet to install the full software update.

Tag: APFS
Related Forum: macOS High Sierra

Top Rated Comments

masotime Avatar
65 months ago
Apple seriously needs to start hiring better QA engineers....
Score: 49 Votes (Like | Disagree)
IPPlanMan Avatar
65 months ago
But we need to have animated emoji faces...
Score: 26 Votes (Like | Disagree)
MasterMac Avatar
65 months ago
Does showing the password itself as the hint count as a password hint? ;)
Score: 23 Votes (Like | Disagree)
Frosties Avatar
65 months ago
Thank you for the laugh. Great alpha software.
Score: 20 Votes (Like | Disagree)
smaffei Avatar
65 months ago
Apple seriously needs to start hiring better QA engineers....
Yes, there some HUGE problems with Apple QA these days.

iOS 11 is riddled with obvious bugs. I just got one about 10 minutes ago. Was just deleting a few voicemails (swipe delete) and the Phone App crashed. Then there is a very reproducible Messages bug where the keyboard obscures the last few messages and you can't get to them. Real rinky-dink stuff that should be caught.

I'm starting to think that Apple is relying too much on the Beta process to collect bugs instead of having robust internal QA.
Score: 18 Votes (Like | Disagree)
RMo Avatar
65 months ago
To be clear, the linked Twitter thread ('https://twitter.com/felix_schwarz/status/915851372217683970/video/1') suggests that this is a Disk Utility bug, where if you create a password-protected volume in Disk Utility it inadvertently sets the hint to the password itself. It's not a bug that allows the password itself to be uncovered via other means, which is what I originally thought this meant and which was surprising to me since the only way to do that should be computationally expensive brute-force methods (the data itself is encrypted with the password; it's not just artificially protected by one, and it shouldn't be possible to "reverse lookup" the password by any true means).
Score: 17 Votes (Like | Disagree)

Popular Stories

apple watch ultra deuglify 1

Apple Watch Ultra User Mods Titanium Casing to 'Deuglify' Design

Tuesday September 27, 2022 8:05 am PDT by
An Apple Watch Ultra user has modified their new device's casing to add a brushed finish and remove the orange color of the Action Button in an effort to make it more visually appealing. The Apple Watch Ultra offers the first complete redesign of the Apple Watch since the product line's announcement in 2014, and while the design has been met with praise from many users, some have criticized...
Dark Sky App Featured

Dark Sky Removed From iOS App Store Ahead of Upcoming Shutdown

Wednesday September 28, 2022 4:27 pm PDT by
The Dark Sky weather app that's owned by Apple is no longer available for download in the U.S. App Store, suggesting that it has been removed ahead of schedule. Apple acquired Dark Sky back in March 2020 and has since incorporated elements of the app into the Weather app available on the iPhone (and soon, the iPad). Dark Sky remained available for purchase as a standalone weather app...
iphone 14 pro max vs 13 max 2

Camera Comparison: iPhone 14 Pro Max vs. iPhone 13 Pro Max

Thursday September 29, 2022 7:44 am PDT by
The iPhone 14 Pro and Pro Max introduce some major improvements in camera technology, adding a 48-megapixel lens and low-light improvements across all lenses with the new Photonic Engine. We've spent the last week working on an in-depth comparison that pits the new iPhone 14 Pro Max against the prior-generation iPhone 13 Pro Max to see just how much better the iPhone 14 Pro Max can be. Subscrib ...
apple watch ultra hammer test

YouTuber Tests Apple Watch Ultra Durability With a Hammer: Table Breaks Before the Watch

Sunday September 25, 2022 2:27 pm PDT by
A YouTuber has put Apple's claims for the durability of the Apple Watch Ultra to the test by putting it up against a drop test, a jar of nails, and repeated hits with a hammer to test the sapphire crystal protecting the display. TechRax, a channel popular for testing the durability of products, first tested the Apple Watch Ultra by dropping it from around four feet high. The Apple Watch...
tony blevins car

Apple Procurement VP Departs Company After Vulgar TikTok Comment

Thursday September 29, 2022 12:38 pm PDT by
Tony Blevins, Apple's vice president of procurement, is set to depart the company after he made a crude comment about his profession in a recent TikTok video, reports Bloomberg. Blevins was in a video by TikTok creator Daniel Mac, who was doing a series on the jobs of people he spotted with expensive cars. After seeing Blevins in an expensive Mercedes-Benz SLR McLaren, Mac asked Blevins what ...
iPhone 14 Pros in Hand Black Background Feature

Verizon iPhone 14 Pro Customers Reporting Cellular Connection Issues

Monday September 26, 2022 6:23 am PDT by
iPhone 14 Pro customers on the Verizon network in the U.S. are reporting issues with slow and unreliable 5G cellular connections and calls randomly dropping. Several threads on Reddit (1,2,3) and the MacRumors forums chronicle issues faced by Verizon customers and Apple's latest iPhone. According to user reports, signal strength on the iPhone 14 Pro is unreliable and weak, while other...
iPhone 15 to Switch From Lightning to USB C in 2023 feature sans arrow

Kuo: iPhone 14 Pro Max Popularity Could Lead to More Differentiation Between iPhone 15 Pro and iPhone 15 Pro Max

Wednesday September 28, 2022 10:22 am PDT by
Apple has seen high demand for the 6.7-inch iPhone 14 Pro Max, which could lead the company to further differentiate the next-generation iPhone 15 Pro and Pro Max, according to Apple analyst Ming-Chi Kuo. Apple could add exclusive features to the iPhone 15 Pro Max in an effort to encourage more people to purchase the larger and more expensive device. Kuo last week said that Apple asked...
iPhone 14 Pro Sports Scores Dynamic Island

iPhone 14 Pro Features Live Sports Scores in Dynamic Island on iOS 16.1

Monday September 26, 2022 7:52 am PDT by
Earlier this month, Apple announced that iOS 16.1 will enable a new Live Activities feature that allows iPhone users to stay on top of things that are happening in real time, such as a sports game or a food delivery order, right from the Lock Screen. On the iPhone 14 Pro and Pro Max, Live Activities also integrate with the Dynamic Island. Premier League match in Dynamic Island via Paul Bradford ...
iOS 16

Everything New in the Latest iOS 16.1 and iPadOS 16.1 Betas: Stage Manager Expansion, Wallpaper Tweaks and More

Tuesday September 27, 2022 11:36 am PDT by
Apple today released new betas of iOS 16.1 and iPadOS 16.1 to developers, tweaking some of the functionality that's been introduced in prior betas and in the case of iPadOS 16.1, adding a major new feature to Stage Manager. We've rounded up everything new in both betas below. Wallpaper Updates Apple has updated the Wallpaper section of the Settings app to allow users to swap between...
General iOS 16 Feature Yellow

Some iOS 16 Users Continue to Face Unaddressed Bugs and Battery Drain Two Weeks After Launch

Monday September 26, 2022 7:34 am PDT by
Today marks exactly two weeks since Apple released iOS 16 to the public. Besides the personalized Lock Screen, major changes in Messages, and new features in Maps, the update has also seen its fair share of bugs, performance problems, battery drain, and more. After major iOS updates, it's normal for some users to report having issues with the new update, but such reports usually subside in...