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.

Top Rated Comments

Quu Avatar
50 months ago
Honestly, what the hell Apple?
Score: 112 Votes (Like | Disagree)
Mr. Donahue Avatar
50 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
50 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
50 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
50 months ago
But emoji karaoke is working well on iPhone X. Whew!
Score: 52 Votes (Like | Disagree)
rpe33 Avatar
50 months ago
I am Root.
Score: 39 Votes (Like | Disagree)

Top Stories

iCloud General Feature

iCloud+'s New Custom Email Domain Feature Now Available in Beta

Wednesday August 25, 2021 7:48 am PDT by
Starting with iOS 15, iPadOS 15, and macOS Monterey, users with a paid iCloud+ storage plan can personalize their iCloud email address with a custom domain name, such as johnny@appleseed.com, and the feature is now available in beta. iCloud+ subscribers interested in setting up a custom email domain can visit the beta.icloud.com website, select "Account Settings" under their name, and select ...
original iphone

Phil Schiller Says iPhone Was 'Earth-Shattering' Ten Years Ago and Remains 'Unmatched' Today

Monday January 9, 2017 7:15 am PST by
To commemorate the tenth anniversary of the iPhone, Apple marketing chief Phil Schiller sat down with tech journalist Steven Levy for a wide-ranging interview about the smartphone's past, present, and future. The report first reflects upon the iPhone's lack of support for third-party apps in its first year. The argument inside Apple was split between whether the iPhone should be a closed...
iphone 12 colors 2021

iPhone 12 Colors: Deciding on The Right Color

Thursday November 5, 2020 8:35 am PST by
The iPhone 12 and iPhone 12 Pro arrived in October 2020 in a range of color options, with entirely new hues available on both devices, as well as some popular classics. The 12 and 12 Pro have different color choices, so if you have your heart set on a particular shade, you might not be able to get your preferred model in that color. iPhone 12 mini and iPhone 12 The iPhone 12 mini and iPhone...
maxresdefault

'Being James Bond' Retrospective Will Be Free to Watch Through Apple TV App

Tuesday August 31, 2021 8:25 am PDT by
Update 9/7/21: "Being James Bond" is now available to watch through the Apple TV app. Ahead of the theatrical release of James Bond film "No Time To Die" on October 8 in the United States, a 45-minute retrospective titled "Being James Bond" will be available to watch for free through the Apple TV app, according to Deadline. The story from MGM is said to feature Daniel Craig reflecting ...
maxresdefault

New MacBook Pro Models Coming at WWDC, Suggests Leaker

Monday May 24, 2021 1:27 pm PDT by
New MacBook Pro models are coming at WWDC, according to leaker Jon Prosser who has a mixed track record when it comes to predicting Apple's plans. Subscribe to the MacRumors YouTube channel for more videos. Prosser provided no additional information, but there are new 14 and 16-inch MacBook Pro models in the works. The new MacBook Pros will feature the most radical redesign to the MacBook Pro ...
calculatorapp

iOS 11 Bug: Typing 1+2+3 Quickly in the Calculator App Won't Get You 6

Tuesday October 24, 2017 2:03 pm PDT by
A bug in the built-in Calculator app in iOS 11 is getting some major attention this week, despite the fact that it's been around since iOS 11 was in beta testing. At issue is a calculator animation that causes some symbols to be ignored when calculations are entered in rapid succession. You can try it for yourself: Type 1+2+3 and then the equals sign into the Calculator app quickly. Due to...
iPhone 13 Dummy Thumbnail 2

Full iPhone 13 Feature Breakdown: Everything Rumors Say We Can Expect

Tuesday August 31, 2021 7:50 am PDT by
With the launch of Apple's iPhone 13 lineup believed to be just a few weeks away, we have compiled all of the coherent rumors from our coverage over the past year to build a full picture of the features and upgrades coming to the company's new smartphones. For clarity, only explicit improvements, upgrades, and new features compared to the iPhone 12 lineup are listed. It is worth noting that...
iPhone 13 Dummy Thumbnail 2

Kuo: iPhone 13 to Feature LEO Satellite Communications to Make Calls and Texts Without Cellular Coverage

Sunday August 29, 2021 7:39 am PDT by
The iPhone 13 will feature low earth orbit (LEO) satellite communication connectivity to allow users to make calls and send messages in areas without 4G or 5G coverage, according to the reliable analyst Ming-Chi Kuo. In a note to investors, seen by MacRumors, Kuo explained that the iPhone 13 lineup will feature hardware that is able to connect to LEO satellites. If enabled with the relevant...
studio buds family

Beats Studio Buds Debuting Today With Active Noise Cancellation, Stemless Design, and More for $150

Monday June 14, 2021 8:00 am PDT by
We've seen a lot of teasers about the Beats Studio Buds over the past month since they first showed up in Apple's beta software updates, and today they're finally official. The Beats Studio Buds are available to order today in red, white, and black ahead of a June 24 ship date, and they're priced at $149.99. The Studio Buds are the first Beats-branded earbuds to truly compete with AirPods...
Top Stories 75 Thumbnail

Top Stories: Last-Minute iPhone 13 Rumors, Apple Announces App Store Changes, and More

Saturday September 4, 2021 6:00 am PDT by
The finish line is in sight! Apple's annual iPhone event is likely just a week or so away and all eyes will be on the company as it unveils the next version of its most popular product line. With any luck, we'll also see the next-generation Apple Watch and perhaps even some new AirPods. Other news this week saw Apple making some more changes to its App Store policies in response to a...