How to Fix The Massive macOS Root Security Bug

How to Fix The Massive macOS Root Security Bug

macOS has a critical 'root' security bug — what you need to do right now

A critical flaw has been discovered in macOS High Sierra that lets an attacker log in as ‘root’ by leaving the password field blank and trying multiple times in a row. Here’s how to “fix” it right now.

“We are working on a software update to address this issue,” an Apple spokesperson told iMore. “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.”

This is a zero-day exploit. Lemi Orhan Ergin tweeted to Apple’s support account that he had discovered a way to log into a Mac running High Sierra by using the superuser “root” and then clicking the login button repeatedly. (Mac’s running Sierra or earlier versions of the OS are not affected.)

Ergin should absolutely have disclosed this to Apple and given the company a chance to patch it before it went public, and Apple should never have allowed the bug to ship, but none of that matters right now.

Here’s what’s important: The “root” account allows super-user access to your system. It’s supposed to be disabled by default on macOS. For whatever reason, it’s not on High Sierra. Instead, “root” is enabled and currently allows access to anyone without a password.

So, anybody who has physical access to your Mac or can get through via screen sharing, VNC, or remote desktop, and enters “root” and hits login repeatedly, can gain complete access to the machine.

Setting “root” password “fixes” the problem:

  1. Click on Apple () at the far left of the menubar.
  2. Click on System Preferences.
  3. Click on Users and Groups.
  4. Click on the Lock (🔒) icon.
  5. Enter your Password.
  6. Click on **Login Options*.
  7. Click on Join or Edit.
  8. Click on Open Directory Utility.
  9. Click on the Lock (🔒) icon.
  10. Enter your Password.
  11. Click on Edit in the menubar.
  12. Click on **Enable Root User*.
  13. Enter and confirm your Root User Password. (Make it a strong, unique one!)

If you prefer the command line, you can:

  1. Launch Terminal.
  2. Type: sudo passwd -u root.
  3. Enter and confirm your Root User Password. (Make it a strong, unique one!)

Do not disable the Root User. That just blanks the password and allows the exploit to work again.

Apple needs to fix this stat. In the meantime, share this information with everyone you know who uses a Mac on High Sierra and make sure they test and validate that “root” access is blocked before you let them resume their day.

source by:-imore

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