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Archive for the ‘FileVault 2’ Category

APFS encryption status check script

November 13, 2017 1 comment

As part of working Apple File System, I’ve developed a script which is designed to check and report the status of encrypted Apple File System (APFS) drives. Currently, here’s what the script is detecting and reporting:

It first checks to see if a Mac is running 10.13.x or higher. If the Mac is question is running 10.13.x or higher, the script reports if it is using encryption on an APFS drive and gives the encryption or decryption status.

If encrypted, the following message is displayed:

FileVault is On.

Screen Shot 2017 11 12 at 8 38 08 PM

 

If not encrypted, the following message is displayed:

FileVault is Off.

Screen Shot 2017 11 12 at 8 43 07 PM

If encrypting, the following message is displayed:

Encryption in progress:

How much has been encrypted is also displayed.

Screen Shot 2017 11 12 at 8 08 30 PM

 

If decrypting, the following message is displayed without quotes:

Decryption in progress:

How much has been decrypted is also displayed.

Screen Shot 2017 11 12 at 8 38 48 PM

 

 

 

If run on a drive which is not using APFS, the following message is displayed:

Unable to display encryption status for filesystems other than APFS.

Screen Shot 2017 11 12 at 8 44 11 PM

 

The script is available below and here on my GitHub repository:

https://github.com/rtrouton/rtrouton_scripts/tree/master/rtrouton_scripts/check_apfs_encryption

I’ve also built a Jamf Pro Extension Attribute:

https://github.com/rtrouton/rtrouton_scripts/tree/master/rtrouton_scripts/Casper_Extension_Attributes/check_apfs_encryption

Unlock an encrypted APFS boot drive using Disk Utility

November 4, 2017 1 comment

In the event that you need to unlock an unbootable boot drive using Apple File System (APFS) encryption, it’s possible to do so using Disk Utility and one of the following authentication credentials:

  1. The password to a FileVault-enabled account on the drive
  2. A personal recovery key

For more details, see below the jump.

Read more…

Unlock or decrypt an encrypted APFS boot drive from the command line

November 4, 2017 3 comments

As part of working with Apple File System (APFS) volumes, it may be necessary to decrypt a boot drive using APFS’s native encryption in order to fix a problem. To decrypt an encrypted APFS boot drive from the command line, you will need to do the following:

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

For more details, see below the jump.

Read more…

Unlocking or decrypting using an institutional recovery key does not work with encrypted APFS boot drives on macOS High Sierra 10.13.0

October 10, 2017 7 comments

As part of Apple’s FileVault 2 encryption, Apple has provided for the use of recovery keys. These keys are a backup method to unlock FileVault 2’s encryption in the event that the usual method of logging using a user’s account password is not available.

There are two main types of recovery keys available:

1. Personal recovery keys (PRK) – These are recovery keys that are automatically generated at the time of encryption. These keys are generated as an alphanumeric string and are unique to the machine being encrypted. In the event that an encrypted Mac is decrypted and then re-encrypted, the existing personal recovery key would be invalidated and a new personal recovery key would be created as part of the encryption process.

Screen Shot 2017 10 10 at 5 24 11 PM

2. Institutional recovery keys (IRK) – These are pre-made recovery keys that can be installed on a system prior to encryption and most often used by a company, school or institution to have one common recovery key that can unlock their managed encrypted systems.

Screen Shot 2017 10 10 at 12 48 16 PM

This recovery key model has continued to be used on Apple File System (APFS), starting with macOS High Sierra 10.13.0, with one important difference:

  • You can encrypt an APFS boot drive using an IRK.
  • You cannot unlock or decrypt an encrypted APFS boot drive using an IRK.

 

Update 11-3-2017: This has been fixed in macOS 10.13.1. For information on how to unlock and decrypt an encrypted APFS boot drive using an IRK, please see the link below:

Unlock or decrypt an encrypted APFS boot drive from the command line


 

For more details, see below the jump.

Read more…

Creating multiline login banners

March 25, 2017 2 comments

In a number of Mac environments, there is a need or requirement for a login banner (otherwise known as a lock message). This message appears in the following locations:

  • FileVault 2 pre-boot login screen
  • OS login window
  • Screensaver lock window

Brevity is best, as staying within a maximum of three lines permits the banner text to be displayed consistently in all three locations. Exceeding the three-line limit may result in the text being cut off and not fully displayed.

You can set this banner text from the command line using the following defaults command, which should be run with root privileges:

/usr/bin/defaults write /Library/Preferences/com.apple.loginwindow LoginwindowText "My Login Window Text Goes Here"

LWScreenShot 2017 03 25 at 11 31 14 AM

Being able to consistently set when lines begin and end can be challenging though, as the defaults command is not able to interpret a newline command natively. However, it is possible to set a multi-line login banner and be able to consistently set when lines begin and end. For more details, see below the jump.

Read more…

Using FileVault 2 recovery keys on FileVault 2-encrypted Macs to provide access for local admins

February 23, 2017 2 comments

It can be difficult to provide consistent access for Mac admins when using a local admin account on FileVault 2-encrypted Macs, due to the way password changes are handled for FileVault 2-enabled accounts. The reason for the difficulty is that FileVault 2’s encryption doesn’t care about passwords, it only cares about encryption keys.

When an account on a particular Mac is enabled for FileVault 2, the account’s password is used to generate an key which can be used to unlock the encrypted Core Storage volume that FileVault 2 sets up on the Mac. When the password for the enabled account gets changed, the password and its associated key are updated by first requesting the previous password (and its associated key) to authenticate the change to the new password and associated key.

Assuming that the old password is provided as part of the password change process, no problem. However, if the old password is not provided as part of the password change process, the new password does not get an associated key to unlock FileVault 2 because the old password’s key was not invoked to authorize the change to a new key. The result of this is that the new password can be used to log into the OS and provide whatever password authorization duties are needed for the OS, but you still need the account’s old password to log into the Mac at the FileVault 2 login screen.

The usual fix for this situation is to run the following commands with root privileges:

1. Remove the user from the list of FileVault 2-enabled accounts

fdesetup remove -user username_goes_here

Figure 25 Using fdesetup remove with username


2. Add the user back to the list of FileVault 2-enabled accounts

fdesetup add -usertoadd username_goes_here

Figure 21 Using fdesetup add usertoadd to enable additional accounts


When the account is re-enabled using the fdesetup add -usertoadd command, a new key is set up for the user and the passwords are back in sync. However, there are two drawbacks to this approach if a Mac admin wants to automate this:

  • You need to provide the password in a non-encrypted format of the account being enabled.
  • You need to provide in a non-encrypted format either a recovery key or the password of another FV 2-enabled account on the Mac.

In short, the passwords and/or recovery key used to remove and re-enable the account in question need to be provided “in the clear”, where anyone successfully intercepting the passwords will be able to read them.

Fortunately, for those Mac admins who have a way to capture and escrow FileVault 2 personal recovery keys, there is an alternative to enabling the local admin account. For more details, see below the jump.

Read more…

Using Disk Utility on macOS Sierra to unlock FileVault 2-encrypted boot drives

October 11, 2016 3 comments

Starting in OS X El Capitan, Apple overhauled Disk Utility’s various functions to add new features and remove others. As of macOS Sierra, it appeared at first that the abilities to unlock or decrypt a FileVault 2-encrypted drive had both been removed from Disk Utility. After some investigation though, it looks like the ability to decrypt has been removed, but you can still unlock using Sierra’s Disk Utility. For more details, see below the jump.

Read more…

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