Major macOS High Sierra Bug Allows Full Admin Access Without Password - How to Fix [Updated]

There appears to be a serious bug in macOS High Sierra that enables the root superuser on a Mac with a blank password and no security check.

The bug, discovered by developer Lemi Ergin, lets anyone log into an admin account using the username "root" with no password. This works when attempting to access an administrator's account on an unlocked Mac, and it also provides access at the login screen of a locked Mac.

rootbug
To replicate, follow these steps from any kind of Mac account, admin or guest:

1. Open System Preferences
2. Choose Users & Groups
3. Click the lock to make changes
4. Type "root" in the username field
5. Move the mouse to the Password field and click there, but leave it blank
6. Click unlock, and it should allow you full access to add a new administrator account.

At the login screen, you can also use the root trick to gain access to a Mac after the feature has been enabled in System Preferences. At the login screen, click "Other," and then enter "root" again with no password.

This allows for admin-level access directly from the locked login screen, with the account able to see everything on the computer.

It appears that this bug is present in the current version of macOS High Sierra, 10.13.1, and the macOS 10.13.2 beta that is in testing at the moment. It's not clear how such a significant bug got past Apple, but it's likely this is something that the company will immediately address.

Until the issue is fixed, you can enable a root account with a password to prevent the bug from working. We have a full how to with a complete rundown on the steps available here.

Update: An Apple spokesperson told MacRumors that a fix is in the works:

"We are working on a software update to address this issue. In the meantime, setting a root password prevents unauthorized access to your Mac. To enable the Root User and set a password, please follow the instructions here: https://support.apple.com/en-us/HT204012. If a Root User is already enabled, to ensure a blank password is not set, please follow the instructions from the 'Change the root password' section."

Update 2: Apple released a security update to address the vulnerability on Wednesday morning. The update can be downloaded on all machines running macOS 10.3.1 using the Software Update mechanism in the Mac App Store. Apple says it will automatically push out the update to all users who have not installed it later in the day.

In a statement provided to MacRumors, Apple said the company's engineers began working on a fix as soon as the problem was discovered. Apple also apologized for the vulnerability and said its development process is being audited to prevent something similar from happening in the future.

Security is a top priority for every Apple product, and regrettably we stumbled with this release of macOS.

When our security engineers became aware of the issue Tuesday afternoon, we immediately began working on an update that closes the security hole. This morning, as of 8 a.m., the update is available for download, and starting later today it will be automatically installed on all systems running the latest version (10.13.1) of macOS High Sierra.

We greatly regret this error and we apologize to all Mac users, both for releasing with this vulnerability and for the concern it has caused. Our customers deserve better. We are auditing our development processes to help prevent this from happening again.

All users should download the new security update immediately.

Related Forum: macOS High Sierra

Top Rated Comments

Quu Avatar
83 months ago
Honestly, what the hell Apple?
Score: 112 Votes (Like | Disagree)
Mr. Donahue Avatar
83 months ago
PUll it together Craig. You’re embarrassing yourself and Apple with iOS 11 and now this? What a shame.
Score: 82 Votes (Like | Disagree)
hamiltonDSi Avatar
83 months ago
10 years ago I started buying Apple products to avoid this kind of bugs.
Funny how things change :)

EDIT one day later :

Apple pushed an update with a fix under 24 hours, this is why i'm still using Apple products :)
Score: 71 Votes (Like | Disagree)
turbineseaplane Avatar
83 months ago
We need an "Even Higher Sierra" release, and only that, this coming year.

High Sierra is just stoned enough that she's letting everyone in...
Maybe if Sierra gets a bit higher, paranoia, and security concerns, might kick in.
Score: 53 Votes (Like | Disagree)
M.PaulCezanne Avatar
83 months ago
But emoji karaoke is working well on iPhone X. Whew!
Score: 52 Votes (Like | Disagree)
rpe33 Avatar
83 months ago
I am Root.
Score: 40 Votes (Like | Disagree)

Popular Stories

reset password request iphone

Warning: Apple Users Targeted in Phishing Attack Involving Rapid Password Reset Requests

Tuesday March 26, 2024 4:34 pm PDT by
Phishing attacks taking advantage of Apple's password reset feature have become increasingly common, according to a report from KrebsOnSecurity. Multiple Apple users have been targeted in an attack that bombards them with an endless stream of notifications or multi-factor authentication (MFA) messages in an attempt to cause panic so they'll respond favorably to social engineering. An...
iPhone Home Screen Gradient Blank Spaces 1

Sources: iOS 18 Lets Apps Be Placed Anywhere on Home Screen Grid

Sunday March 24, 2024 1:33 pm PDT by
iOS 18 will give iPhone users greater control over Home Screen app icon arrangement, according to sources familiar with the matter. While app icons will likely remain locked to an invisible grid system on the Home Screen, to ensure there is some uniformity, our sources say that users will be able to arrange icons more freely on iOS 18. For example, we expect that the update will introduce...
iPad Pro 2024 Landscape Camera Feature

New iPad Pro Again Rumored to Feature Landscape Front-Facing Camera

Monday March 25, 2024 5:43 am PDT by
The next-generation iPad Pro will feature a landscape-oriented front-facing camera for the first time, according to the Apple leaker known as "Instant Digital." Instant Digital reiterated the design change earlier today on Weibo with a simple accompanying 2D image. The post reveals that the entire TrueDepth camera array will move to the right side of the device, while the microphone will...
maxresdefault

Apple Announces WWDC 2024 Event for June 10 to 14

Tuesday March 26, 2024 10:02 am PDT by
Apple today announced that its 35th annual Worldwide Developers Conference is set to take place from Monday, June 10 to Friday, June 14. As with WWDC events since 2020, WWDC 2024 will be an online event that is open to all developers at no cost. Subscribe to the MacRumors YouTube channel for more videos. WWDC 2024 will include online sessions and labs so that developers can learn about new...
sonoma desktop wwdc

Apple Releases macOS Sonoma 14.4.1 With Fix for USB Hub Bug

Monday March 25, 2024 10:10 am PDT by
Apple today released macOS Sonoma 14.4.1, a minor update for the macOS Sonoma operating system that launched last September. macOS Sonoma 14.4.1 comes three weeks after macOS Sonoma 14.4. The ‌‌‌‌macOS Sonoma‌‌ 14.4‌.1 update can be downloaded for free on all eligible Macs using the Software Update section of System Settings. There's also a macOS 13.6.6 release for those who...
Generic iOS 18 Feature Purple

iOS 18 Will Finally Bring This Android Feature to iPhone

Monday March 25, 2024 6:42 am PDT by
iOS 18 will allow iPhone users to place app icons anywhere on the Home Screen grid, according to sources familiar with development of the software update. This basic feature has long been available on Android smartphones. While app icons will likely remain locked to an invisible grid system on the Home Screen, our sources said that users will be able to arrange icons more freely on iOS 18....
apple maps 3d feature

Apple Maps May Gain Custom Routes With iOS 18

Tuesday March 26, 2024 3:10 pm PDT by
Apple may be planning to add support for "custom routes" in Apple Maps in iOS 18, according to code reviewed by MacRumors. Apple Maps does not currently offer a way to input self-selected routes, with Maps users limited to Apple's pre-selected options, but that may change in iOS 18. Apple has pushed an iOS 18 file to its maps backend labeled "CustomRouteCreation." While not much is revealed...