Mac FileVault Encryption

This feature is available in Professional, Free, and Trial editions of MDM.

Introduction

Encrypting information stored in employee computers is mandated in most organizations. Encryption ensures that the information on these computers can only be accessed by authorised users. The users authenticate themselves with their login credentials, which inturn decrypts the information for access.

Filevault is the most preferred tool for encrypting the data on mac machines. It provides two methods for encrypting the data on the systems.

  1. Encryption using iCloud password
  2. Encryption using institutional recovery key

Encryption using Mobile Device Manager Plus

Though users can manually encrypt their systems, it is always recommended to use a device management solution to encrypt the managed systems. This ensures uniformity in the encryption process used and also that all the users have encrypted their devices. Using Mobile Device Manager Plus to perform FileVault encryption on Mac machines also has the following benefits

Using Mobile Device Manager Plus, a Mac system can be encrypted using any of the following methods

  1. Personal recovery key
  2. Institutional recovery key
  3. Personal and institutional recovery key 

Encryption using personal recovery key

Filevault allows users to generate a personal recovery key that can be used to access their encrypted data in addition to their login credentials. If the user forgets his login password the user will be prompted to enter this generated recovery key to decrypt his system.

Mobile Device Manager Plus supports encryption using a recovery key. The recovery key generated during encryption can then be posted to the Mobile Device Manager Plus server. This ensures the users can request their organization's IT admins to provide them the recovery key to access their data. Since the personal recovery key is specific to users, this also prevents any unauthorised use of the recovery key.

Follow the steps given here to encrypt data using personal recovery key. 

  1. On the MDM console, navigate to Device Mgmt ->Apple profile
  2. Enter a name for the profile and select FileVault Encryption
  3. Enable the option to use personal recovery key to encrypt user's mac systems.
  4. You can choose to show the generated key to the user, to allow them to make a note of it.
  5. Save and publish the profile.
  6. You can then distribute this profile to either groups or devices.

Encryption using institutional recovery key

Organizations can also choose to just use a single key or a certificate to encrypt the mac systems of the employees. To use a certificate to encrypt the systems, the administrator must first create the certificate and upload it to the MDM server.

To use institutional recovery key to encrypt the systems, the admin has to perform the following steps

  1. Create a certificate for encryption
  2. Uploading certificate to Mobile Device Manager Plus

Creating Certificate

This section explains the steps to create and export the institutional recovery key-

  1. On an administrator computer, open Terminal and execute the following command: sudo security create-filevaultmaster-keychain /Library/Keychains/FileVaultMaster.keychain
  2. Enter the login password/credential.
  3. Create a password for the new keychain when prompted. This password will be used to access the keychain certificate created in the next few steps. A keychain FileVaultMaster.keychain is created in the following location /Library/Keychains/
  4. You will have to unlock the keychain to copy or edit the created keychain. Enter the following command in the terminal to unlock the keychain-security unlock-keychain /Library/Keychains/FileVaultMaster.keychain
  5. Enter the previously created keychain password to unlock the keychain.
  6. Open Keychain Access.
  7. From the menu bar, choose File->Add Keychain
  8.  
  9. Press Cmd+up to move up in the folder hierarchy. Continue till it reaches the last page, select the disk and then navigate to /Library/Keychains/ to find the created keychain.
  10.  
  11. Select the FileVaultMaster.keychain file located in this folder.
  12. Select FileVaultMaster under the Keychains heading in the sidebar, and then select All Items under the Category heading in the sidebar.
  13. Verify that a private key is associated with the certificate. Select the certificate and the private key.
  14. From the menu bar, choose File -> Export Items and save the items as a .p12 file.
  15. The .p12 file is a bundle that contains both the FileVault Recovery Key and the private key.
  16. Create and verify another password to secure the file, and then click OK.
  17. You will be prompted to enter this password when uploading the recovery key.
  18. Delete the key chain you created.
  19. Quit Keychain Access.

The FileVault Recovery Key and the private key are saved as a .p12 file in the location you specified. This file can be used to encrypt the user's computers.

Uploading the certificate in Mobile Device Manager Plus

Once the required certificate is created, the admin has to upload this certificate to the Mobile Device Manager Plus console and distribute it to the systems to be encrypted. Follow the steps given below to upload and distribute the institutional recovery key.

  1. On the MDM console, navigate to Device Management -> Profiles
  2. Select Apple from the drop box that appears on clicking Create Profile.
  3. Click on FileVault Encryption.
  4. Select Institutional Recovery Key certificate as the encryption method
  5. Browse and upload the .p12 file certificate created. Save and publish the profile.

This profile can then be distributed to the required groups and devices.

Encrypting using both Personal and Institutional Recovery key

Mobile Device Manager Plus also allows the admin to encrypt the systems using both a personal recovery key and the institutional recovery key. This is helpful when the data is to be decrypted, the user can choose which method to use to decrypt their data.

Steps to encrypt using personal and institutional recovery key.

  1. On the MDM console, navigate to Device Management -> Profiles
  2. Select Apple from the drop box that appears on clicking Create Profile.
  3. Click on FileVault Encryption.
  4. Select Personal and Institutional Recovery key as the encryption method
  5. Upload the certificate, and if needed, allow the users access to their personal recovery key.
  6. Save and publish the profile.
  7.  
  8. Distribute the profile to required groups and devices.

Decrypting mac systems when users forget their passwords

If a user forgets their passwords the user can contact the admin to decrypt their systems. The admin can check the encryption method used to encrypt the system by navigating to Inventory, selecting the device name and clicking on FileVault Encryption tab. Based on the type of encryption used, the admin has two options to decrypt the system.

  1.  Personal recovery key- If the user has the recovery key handy, they can enter this key in the login page when prompted. They can also obtain this key from the Mobile Device Manager Plus server from the page where the encryption method details are available. Once the recovery key is entered, the user will be asked to set a new password.
  2. Institutional recovery key- If institutional recovery key is used, then the system cannot be decrypted directly, the user can only retrieve the encrypted files. The system will then have to be wiped and the files be restored into the system. The admin can access the certificate used for encryption by navigating to Inventory ->Device name -> FileVault Encryption. Download the certificate.To decrypt the system that is encrypted using institutional recovery key, the admin has to follow the steps given below-

Converting p12 to keychain format

  1. On a mac machine, navigate to Keychain Access
  2. Create a new keychain by navigating to File->New keychain
  3. Enter FileVaultMaster as the name for the keychain and secure it using a password
  4. Select the created keychain and navigate to File->Import Items
  5. Select the .p12 certificate downloaded from Mobile Device Manager Plus
  6. Enter the password for the certificate specified while downloading from Mobile Device Manager Plus

Unlock A Filevault 2-encrypted Volume With An Institutional Recovery Key

Requirements Steps
  1. On the administrator's system, where the originally created keychain (institutional recovery key) is stored. Copy FileVaultMaster.keychain-db along with the private key to an external drive or USB drive
  2. Boot the machine that has to be decrypted,  in recovery mode, by holding command-R while starting up.
  3. To unlock  the keychain

  4. Plug in the USB or external drive with the FileVaultMaster keychain to the device to be decrypted. Once in recovery mode, the drive should automatically mount, doesn't, you can also mount it using Disk Utility.
  5. Open Terminal by navigating to Utilities->Terminal
  6. Unlock the keychain in the Terminal, by running the command security unlock-keychain /Volumes/[nameofdrive]/[path]/FileVaultMaster.keychain . When prompted, enter the password that was used to create the keychain.
  7.  
  8. Entering the correct password will unlock the keychain.

    Unlock the encrypted volume

    MacOS devices running macOS High Sierra (10.13) may have been upgraded to Apple’s new APFS. Follow the steps below to unlock the encrypted volume

  1. If your device is using APFS, find the APFS disk role by using diskutil apfs list.
  2. Unlock the encrypted volume by using diskutil apfs unlockVolume [APFS disk role] -recoverykeychain /Volumes/[nameofdrive]/FileVaultMaster.keychain
  3. You can now browse the directories of the unlocked drive, or you can decrypt the drive and turn off.
  4. You can then decrypt the files using diskutil apfs decryptVolume /dev/[APFS disk role] You can check the progress by running diskutil apfs list again.

If you are still using mac version lower than 10.13 follow the steps given below to unlock and decrypt the volume

  1.  If your device is using macOS Extended (HFS+), find the CoreStorage Volumes (UUID) by using diskutil cs list
  2. Find the Logical Volume UUID of the encrypted drive, by running the command diskutil corestorage list
  3. Unlock the volume with diskutil corestorage unlockVolume [UUID] -recoveryKeyChain /Volumes/[nameofdrive]/[path]/FileVaultMaster.keychain
  4. The volume should unlock and mount, you can now retrieve the files.
  5. Decrypt the files using diskutil corestorage revert [UUID] -recoveryKeychain /Volumes/[nameofdrive]/[path]/FileVaultMaster.keychain



See Also:  Associating Profiles to Groups, Associating Profiles to Devices,  App Management, Distribute Apps to Devices, Distribute Apps to Groups
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