Archive for the ‘Mac administration’ Category

Secure Token and FileVault on Apple File System

January 20, 2018 5 comments

As part of Apple File System’s FileVault encryption on mac OS High Sierra, Apple introduced Secure Token. This is a new and undocumented account attribute, which is now required to be added to a user account before that account can be enabled for FileVault on an encrypted Apple File System (APFS) volume. To help make sure that at least one account has a Secure Token attribute associated with it, a Secure Token attribute is automatically added to the first account to log into the OS loginwindow on a particular Mac.

Users and groups preference pane only user gets secure token automatically

Once an account has a Secure Token associated with it, it can then create other accounts which will in turn automatically be granted their own Secure Token.

For the consumer user, this usually takes the following form:

  1. Secure Token is automatically enabled for the user account created by Apple’s Setup Assistant.
  2. The Setup Assistant-created user account with Secure Token then creates other users via the Users & Groups preference pane in System Preferences. Those accounts get their own Secure Token automatically.

However, Active Directory mobile accounts and user accounts created using command line tools do not automatically get Secure Token attributes associated with these accounts. Without the Secure Token attribute, those accounts are not able to be enabled for FileVault.

Filevault preference pane account without secure token cannot manage filevault

Update 1-20-2018: @mikeymikey has pointed out an exception to the rule:

Instead, the sysadminctl utility must be used to grant Secure Token to these accounts as a post-account creation action. In that case, the sysadminctl utility must be run by a user account with the following pre-requisites:

  1. Administrative rights
  2. Secure Token

For more details, please see below the jump.

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Oracle Java 9 JDK and JRE installation scripts for macOS

January 18, 2018 Leave a comment

Oracle has started to release Java 9 for macOS, so I’m posting a couple of scripts to download and install the following:

Oracle Java 9 JRE
Oracle Java 9 JDK

Oracle has been releasing two separate versions of Java 8 simultaneously and may do the same for Java 9, so these Java 9-focused scripts are designed to allow the user to set which version they want to install: the CPU release or the PSU release.

The difference between CPU and PSU releases is as follows:

  • Critical Patch Update (CPU): contains both fixes to security vulnerabilities and critical bug fixes.
  • Patch Set Update (PSU): contains all the fixes in the corresponding CPU, plus additional fixes to non-critical problems.

For more details on the differences between CPU and PSU updates, please see the link below:

For more information, please see below the jump.

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Setting your Mac to receive macOS beta updates using seedutil

January 6, 2018 Leave a comment

As part of a discussion of how to build test VMs, a colleague mentioned how they were using the seedutil tool to help configure Macs to access Apple’s beta updates. I hadn’t run across this tool before, so I decided to do some research and see if I could make it work for my own testing needs. For more details, see below the jump.

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Decrypting an APFS encrypted volume using diskutil on macOS 10.13.2

December 31, 2017 2 comments

Apple has made changes as of macOS 10.13.2 to the way you can turn off APFS encryption when using the diskutil apfs decryptVolume command.

On macOS 10.13.0 and 10.13.1, an APFS encrypted volume could be decrypted using the following procedure:

  1. Identify the relevant encrypted APFS volume
  2. Unlock the encrypted APFS volume
  3. Decrypt the encrypted APFS volume

Once the drive has been unlocked, you could then decrypt the APFS volume using the command shown below:

diskutil apfs decryptVolume /dev/apfs_volume_id_here

As long as you were using root or admin privileges to run the command, no additional authentication was required to decrypt an unlocked encrypted volume.

Screen Shot 2017 11 03 at 11 02 23 PM

However, the diskutil apfs decryptVolume command has been updated on macOS 10.13.2 to require additional authentication:

In order to decrypt using a user account’s password or personal recovery key (PRK), it is necessary to specify the following:

  1. The relevant user UUID
  2. The relevant account password or the PRK.

Note: As of macOS 10.13.2, it is not possible to decrypt an encrypted APFS volume using an institutional recovery key (IRK). You can unlock an encrypted APFS volume using an IRK, but diskutil apfs decryptVolume does not include functionality for using an IRK to authenticate the decryption of an encrypted APFS volume.

For more details, please see below the jump.

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Creating local user accounts with pycreateuserpkg

December 24, 2017 1 comment

As part of setting up new Macs, you may want to add one or more local user accounts with a pre-determined password to those Macs. The reasons for this may include the following:

  • Setting up a local administrator account
  • Setting up a “loaner” user account for a pool of loaner laptops
  • Setting up a local user account that automatically logs at startup for a library kiosk
  • Setting up a generic “student” account for use in a school’s computer lab

Previously, it was possible to use the venerable CreateUserPkg utility to accomplish this goal, but the password scheme used by CreateUserPkg stopped working on macOS High Sierra. An alternative tool which works on macOS High Sierra is pycreateuserpkg, a Python script written by Greg Neagle which generates packages that create local user accounts when installed. For more information, see below the jump.

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Security Update 2017-001 being pushed to both macOS 10.13.0 and 10.13.1

November 30, 2017 4 comments

To fix the vulnerability popularly referred to as #IAMROOT , Apple has begun pushing Security Update 2017-001 to Macs running the following OS versions:

  • macOS 10.13.0
  • macOS 10.13.1

This update is being deployed using the same automated installation mechanism that Apple previously used to deploy OS X NTP Security Update 1.0 back in 2014, where Security Update 2017-001 is being silently downloaded and installed on vulnerable Macs.

Screen Shot 2017 11 30 at 2 08 59 PM

For more details, please see below the jump.

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Categories: Mac administration, macOS

Blocking logins to the root account on macOS High Sierra

November 28, 2017 7 comments

A security vulnerability was discovered in macOS High Sierra today, where you could enable and log into the root account without providing a password.

Update 11-29-2017: Apple has released Security Update 2017-001 to fix this issue. Please install this update as soon as possible.

Update 11-30-2017: Apple is now automatically installing Security Update 2017-001 on vulnerable Macs.

To address this this issue until Apple releases an update to fix it, there’s two steps you can take which will block logins to the root account:

  1. Set a password for the root account on your Mac
  2. Change the root’s account’s login shell to /usr/bin/false

When you set the root account’s login shell to /usr/bin/false, the shell is changed to point to a command that does nothing except return a status code which reports an error. The login process will interpret that error status code as being a failed login, so it will stop the login process at that point and prompt for the password again.

Since the login process will always receive the error code from the false command, the login process will never succeed. For more details, see below the jump.

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Categories: Mac administration, macOS
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