Vulnerability Discussion

If FileVault is enabled, automatic log on must be disabled, so that both FileVault and login window authentication are required.

The default behavior of macOS when FileVault is enabled is to automatically log on to the computer once successfully passing user's FileVault credentials.

Note: DisableFDEAutoLogin does not have to be set on Apple Silicon-based macOS systems that are smartcard enforced, as smartcards are available at preboot.

Check

Verify the macOS system is configured to disable filevault automatic login with the following command:

/usr/bin/osascript -l JavaScript << EOS
$.NSUserDefaults.alloc.initWithSuiteName('com.apple.loginwindow')\
.objectForKey('DisableFDEAutoLogin').js
EOS

If the result is not "true", this is a finding.

Fix

Configure the macOS system to disable filevault automatic login by installing the "com.apple.loginwindow" configuration profile.

Note: To ensure continued access to the operating system, consult the supplemental guidance provided with the STIG before applying the configuration profile.