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

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Information

This policy setting allows you to control how BitLocker-protected removable data drives are recovered in the absence of the required credentials. 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:
Administrators should always have a safe, secure way to access encrypted data in the event users cannot access their data.
Additionally, as with any authentication method, a drive can be compromised by guessing or finding the authentication information used to access the drive.
To use BitLocker a Data Recovery Agent will need to be configured for removable drives. To recover a drive will require highly-controlled access to the Data Recovery Agent private key.

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\Removable Data Drives\Choose how BitLocker-protected removable 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 removable drives.

Default Value:
Recovery options are specified by the user.

References:
1. CCE-35704-6

See Also

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