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

Popular Stories

maxresdefault

iPhone SE 4 With Face ID Said to Be Priced Below $500

Monday May 20, 2024 3:43 am PDT by
Apple is targeting a sub-$500 starting price for its upcoming fourth-generation iPhone SE model despite a raft of rumored upgrades coming to the more affordable device. According to leaker Revegnus on X, the U.S. launch price of the fourth-generation iPhone SE will either remain at the same $429 starting price as the current model, or will see an increase of around 10%. Either way, Apple's...
iOS 17

Apple Releases iOS 17.5.1 With Fix for Reappearing Photos Bug

Monday May 20, 2024 10:11 am PDT by
Apple today released iOS 17.5.1 and iPadOS 17.5.1, minor updates to the iOS 17 and iPadOS 17 operating system updates that came out last September. The 17.5.1 updates come a week after the launch of iOS 17.5 and iPadOS 17.5. iOS 17.5.1 and iPadOS 17.5.1 can be downloaded on eligible iPhones and iPads over-the-air by going to Settings > General > Software Update. According to Apple's...
iPhone 16 Camera Lozenge 2 Perspective

iPhone 16 Lineup Rumored to Come in These Two New Colors

Sunday May 19, 2024 11:08 am PDT by
Apple analyst Ming-Chi Kuo today outlined his expectations for the iPhone 16 lineup's color options, revealing that two new colors should replace two of the existing shades. Kuo outlined his expectations in a post on X (formerly Twitter) earlier today. He believes that the iPhone 16 Pro and iPhone 16 Pro Max will be available in black, white or silver, gray or "Natural Titanium," and rose....
microsoft surface pro qualcomm

Microsoft Says New Surface Pro is Faster Than 15" M3 MacBook Air

Monday May 20, 2024 3:19 pm PDT by
Microsoft is going all in on AI, today introducing a series of Copilot+ PCs that have AI-focused hardware. The new Surface Pro is one of the first Copilot+ PCs, equipped with Qualcomm's Arm-based Snapdragon X Elite processor. Microsoft is already pitting the Surface Pro against Apple's M3 MacBook Air, and in marketing materials, claims that the Surface Pro has superior processing power and...
iOS 17

iOS 17.5 Bug May Also Resurface Deleted Photos on Wiped, Sold Devices [Updated]

Friday May 17, 2024 12:24 pm PDT by
A bug in iOS 17.5 is apparently causing photos that have been deleted to reappear, and the issue seems to impact even iPhones and iPads that have been erased and sold off to other people. A Reddit user wiped an iPad following Apple's guidelines in September of 2023 before selling it off to a friend. That friend updated the iPad to iPadOS 17.5 this week, and began seeing the Reddit user's old ...
iphone se 4 modified flag edges

When to Expect the Next iPhone SE to Launch

Friday May 17, 2024 2:03 pm PDT by
It has been over two years since Apple released the third-generation iPhone SE, and rumors continue to surface about a new model. The latest word comes from The Information, which today reported that Apple plans to release a new iPhone SE with a design similar to the standard iPhone 14 in the spring of 2025. If this rumor is accurate, the iPhone SE would finally gain Face ID and a notch...

Top Rated Comments

masotime Avatar
87 months ago
Apple seriously needs to start hiring better QA engineers....
Score: 49 Votes (Like | Disagree)
IPPlanMan Avatar
87 months ago
But we need to have animated emoji faces...
Score: 26 Votes (Like | Disagree)
MasterMac Avatar
87 months ago
Does showing the password itself as the hint count as a password hint? ;)
Score: 23 Votes (Like | Disagree)
Frosties Avatar
87 months ago
Thank you for the laugh. Great alpha software.
Score: 20 Votes (Like | Disagree)
smaffei Avatar
87 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
87 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)