18.9.11.2.6 (BL) Ensure 'Choose how BitLocker-protected operating system drives can be recovered: Recovery Key' is set to 'Enabled: Do not allow 256-bit recovery key'

Information

This policy setting allows you to control how BitLocker-protected operating system drives are recovered in the absence of the required startup key information. This policy setting is applied when you turn on BitLocker.
In 'Configure user storage of BitLocker recovery information' select whether users are allowed, required, or not allowed to generate a 48-digit recovery password or a 256-bit recovery key.
The recommended state for this setting is: Enabled: Do not allow 256-bit recovery key.

Rationale:
Should a user lose their primary means for accessing an encrypted OS volume, or should the system not pass its boot time integrity checks, the system will go into recovery mode. If the recovery key has not been backed up to Active Directory, the user would need to have saved the recovery key to another location such as a USB flash drive, or have printed the recovery password, and now have access to one of those in order to recovery the system. If the user is unable to produce the recovery key, then the user will be denied access to the encrypted volume and subsequently any data that is stored there.

Solution

To establish the recommended configuration via GP, set the following UI path to Enabled: Do not allow 256-bit recovery key:
Computer Configuration\Policies\Administrative Templates\Windows Components\BitLocker Drive Encryption\Operating System Drives\Choose how BitLocker-protected operating system drives can be recovered: Recovery Key
Note: This Group Policy path may not exist by default. It is provided by the Group Policy template VolumeEncryption.admx/adml that is included with the Microsoft Windows 7 & Server 2008 R2 Administrative Templates (or newer).

Impact:
A 256-bit recovery key will not be permitted for the operating system drive. Users will need to be domain connected to turn on BitLocker. This policy is not FIPS complaint.

Default Value:
Recovery options are specified by the user.

References:
1. CCE-33101-7

See Also

https://workbench.cisecurity.org/files/2754

Item Details

Category: ACCESS CONTROL, CONTINGENCY PLANNING

References: 800-53|AC-19(5), 800-53|CP-9, CSCv6|10.3, CSCv6|13.2, CSCv7|10.4, CSCv7|13.6

Plugin: Windows

Control ID: 552ca64e5fc8cd343fae3eb1ae0c973a84be3818eeac1761cbdb6d53fb7a58e1