Apple Shoots Itself In The Foot As Fix For Glaring macOS High Sierra Exploit Breaks File Sharing

Apple seems to be having a tough time getting out of its own way, in regards to a dopey security flaw that was recently discovered and fixed. The flaw allowed users to gain administrative access to systems running macOS High Sierra by typing "root" for the username and leaving the password blank. Apple rolled out a fix, but in doing so it created a new problem that prevented Mac users from authenticating or connecting to file shares.

"Immediately after installing this patch, file sharing fails to authenticate. I see this on multiple Macs. Hoping for some collaboration," a MacRumors forum member wrote. When asked by another forum member to elaborate, he explained, "With the Finder open, a file share to any Mac with the security update installed. Status shows 'not connected' when you try to 'connect as' your username and password fail."

It is an annoying bug, albeit one that can be squashed with a few simple steps. As outlined in a new support document on Apple's website, affected users should perform the following:

1. Open the Terminal app, which is in the Utilities folder of your Applications folder.
2. Type sudo /usr/libexec/configureLocalKDC and press Return.
3. Enter your administrator password and press Return.
4. Quit the Terminal app.

Once those steps are performed, affected users running macOS High Sierra 10.13.1 (current version) should have no further trouble with file sharing on their Mac.


As to the original security flaw that allows someone to gain administrative rights by typing "root" as the username and leaving the password field blank, it remains unfixed in the macOS High Sierra 10.13.2 beta, which is available to developers and public beta testers. Affected users waiting for a fix can, in the meantime, activate an account with the "root" username and a password.

Going forward, Mac users can cross their fingers that this is the last major bug that appears. It is certainly not the first. A bug in High Sierra caused iMessage delivery errors for some users, while another bug in the OS exposed passwords for encrypted APFS volumes. Yet another flaw in the OS allowed programs that weren't approved by Apple the opportunity to steal passwords from the Mac keychain.