BitLocker Guidance

About Microsoft BitLocker

Microsoft BitLocker is a full volume encryption feature built into Windows. BitLocker is intended to protect data on devices that have been lost or stolen. BitLocker is available in the Ultimate and Enterprise editions of Windows Vista and Windows 7, in the Professional and Enterprise editions of Windows 8/8.1, and in the Pro, Enterprise, and Education editions of Windows 10. BitLocker is also included in the Windows Server releases of Windows since Window Server 2008.

The Windows 10 BitLocker modules have been validated against NIST FIPS 140-2 program multiple times:

• June 2, 2016 certificate numbers 2601, 2602, and 2603.
• August 26, 2016 certificate numbers 2701, 2702, 2703.
• January 26, 2017 certificate numbers 2932, 2933, and 2934.

About this repository

This repository hosts Group Policy Objects, compliance checks, and configuration tools in support of implementing BitLocker.

A BitLocker PowerShell module has been provided to aid in provisioning BitLocker on standalone systems. Group Policy and Microsoft SCCM 1910 CB can be used for provisioning BitLocker on domain joined systems.

BitLocker settings

NSA Cybersecurity recommends using the newest BitLocker settings in the Microsoft Windows Security Baseline, available in the Security Compliance Toolkit, with the following modifications:

• The Choose drive encryption method and cipher strength (Windows 10 [Version 1511] and later) > Select the encryption method for removable data drives policy under can be set to XTS-AES 256-bit or AES-CBC 256-bit instead of just AES-CBC 256-bit. AES-CBC 256-bit is allowed so operating system releases before Windows 10 1511 will be able read the encrypted media.
• The Deny write access to removable drives not protected by BitLocker policy under Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Removable Data Drives can be set to Not Configured instead of Enabled. BitLocker is not used for Data Loss Prevention in DoD.
• The Configure minimum PIN length for startup policy under Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives can be set to 6 or higher instead of 7. A value of 6 aligns with the Mobile Device Fundamentals Protection Profile.
• The Disable new DMA devices when this computer is locked policy under Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption can be set to Enabled or Not Configured. This policy has known issues that may lead to certain built-in devices (network, audio, etc) not working, or a slow system boot, in Windows 10 1709.
• Any settings that reinforce default behaviors are considered optional for configuration:
  • Allow Secure Boot for integrity validation policy under Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives can be set to Enabled or Not Configured.
• PIN settings are only required when a startup PIN is desired.

General settings

View the policies as a CSV which is easier to read than the table below and is also searchable.

Policy Path	Policy Name	Policy State	Policy Value	Registry Path	Registry Value Name	Registry Data Value	Applicable Client	Applicable Server	Required for Applicable OS
Computer Configuration > System > Device Installation > Device Installation Restrictions	Prevent installation of devices that match any of these Device IDs > Prevent installation of devices that match any of these Device IDs:	Enabled	PCI\CC_0C0A	HKLM\Software\Policies\Microsoft\Windows\DeviceInstall\Restrictions	DenyDeviceIDs	1	Windows Vista+	Windows Server 2008+	Yes
Computer Configuration > System > Device Installation > Device Installation Restrictions	Prevent installation of devices that match any of these Device IDs > Prevent installation of devices that match any of these Device IDs:	Enabled		HKLM\Software\Policies\Microsoft\Windows\DeviceInstall\Restrictions	DenyDeviceIDsRetroactive	1	Windows Vista+	Windows Server 2008+	Yes
Computer Configuration > System > Device Installation > Device Installation Restrictions	Prevent installation of devices using drivers that match these device setup classes > Prevent installation of devices using drivers that match these device setup classes:	Enabled	{d48179be-ec20-11d1-b6b8-00c04fa372a7}	HKLM\Software\Policies\Microsoft\Windows\DeviceInstall\Restrictions	DenyDeviceClasses	1	Windows Vista+	Windows Server 2008+	Yes
Computer Configuration > System > Device Installation > Device Installation Restrictions	Prevent installation of devices using drivers that match these device setup classes > Prevent installation of devices using drivers that match these device setup classes:	Enabled		HKLM\Software\Policies\Microsoft\Windows\DeviceInstall\Restrictions	DenyDeviceClassesRetroactive	1	Windows Vista+	Windows Server 2008+	Yes
Computer Configuration > System > Power Management > Sleep Settings	Allow standby states (S1-S3) when sleeping (on battery)	Disabled		HKLM\Software\Policies\Microsoft\Power\PowerSettings\abfc2519-3608-4c2a-94ea-171b0ed546ab	DCSettingIndex	0	Windows Vista+	Windows Server 2008+	Yes
Computer Configuration > System > Power Management > Sleep Settings	Allow standby states (S1-S3) when sleeping (plugged in)	Disabled		HKLM\Software\Policies\Microsoft\Power\PowerSettings\abfc2519-3608-4c2a-94ea-171b0ed546ab	ACSettingIndex	0	Windows Vista+	Windows Server 2008+	Yes
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Choose how BitLocker-protected operating system drives can be recovered	Enabled		HKLM\Software\Policies\Microsoft\FVE	OSRecovery	1	Windows 7+	Windows Server 2008 R2+	Yes (domain joined systems only)
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Choose how BitLocker-protected operating system drives can be recovered > Save BitLocker recovery information to AD DS for operating system drives		Save BitLocker recovery information to AD DS for operating system drives	HKLM\Software\Policies\Microsoft\FVE	OSActiveDirectoryBackup	1	Windows 7+	Windows Server 2008 R2+	Yes (domain joined systems only)
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Choose how BitLocker-protected operating system drives can be recovered > Configure storage of BitLocker recovery information to AD DS		Store recovery passwords and key packages	HKLM\Software\Policies\Microsoft\FVE	OSActiveDirectoryInfoToStore	1	Windows 7+	Windows Server 2008 R2+	Yes (domain joined systems only)
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Choose how BitLocker-protected operating system drives can be recovered > Do not enable BitLocker until recovery information is stored in AD DS for operating system drives		Do not enable BitLocker until recovery information is stored in AD DS for operating system drives	HKLM\Software\Policies\Microsoft\FVE	OSRequireActiveDirectoryBackup	1	Windows 7+	Windows Server 2008 R2+	Yes (domain joined systems only)
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption	Choose drive encryption method and cipher strength (Windows 10 [Version 1511] and later) > Select the encryption method for operating system drives	Enabled	XTS-AES 256-bit	HKLM\Software\Policies\Microsoft\FVE	EncryptionMethodWithXtsOs	7	Windows 10 1511+	Windows Server 2016+	Yes
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption	Choose drive encryption method and cipher strength (Windows 10 [Version 1511] and later) > Select the encryption method for fixed data drives	Enabled	XTS-AES 256-bit	HKLM\Software\Policies\Microsoft\FVE	EncryptionMethodWithXtsFdv	7	Windows 10 1511+	Windows Server 2016+	No
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption	Choose drive encryption method and cipher strength (Windows 10 [Version 1511] and later) > Select the encryption method for removable data drives	Enabled	XTS-AES 256-bit or AES-CBC 256-bit	HKLM\Software\Policies\Microsoft\FVE	EncryptionMethodWithXtsRdv	4 or 7	Windows 10 1511+	Windows Server 2016+	No
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption	Choose drive encryption method and cipher strength (Windows 8, Windows Server 2012, Windows 8.1, Windows Server 2012 R2, Windows 10 [Version 1507]) > Select encryption method	Enabled	AES 256-bit	HKLM\Software\Policies\Microsoft\FVE	EncryptionMethodNoDiffuser	4	Windows 8 - Windows 10 1507	Windows Server 2012 - Windows Server 2012 R2	Yes
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption	Choose drive encryption method and cipher strength (Windows Vista, Windows Server 2008, Windows 7, Windows Server 2008 R2) > Select encryption method	Enabled	AES 256-bit	HKLM\Software\Policies\Microsoft\FVE	EncryptionMethod	2	Windows Vista - Windows 7	Windows Server 2008 - Windows Server 2008 R2	Yes
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption	Disable new DMA devices when this computer is locked	Enabled		HKLM\Software\Policies\Microsoft\FVE	DisableExternalDMAUnderLock	1	Windows 10 1703+	N/A	Yes
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Allow Secure Boot for integrity validation	Enabled or Not Configured		HKLM\Software\Policies\Microsoft\FVE	OSAllowSecureBootForIntegrity or not exist	1 or not exist	Windows 8+	Windows Server 2012+	No

PIN related settings

Some environments may desire additional protection provided by a BitLocker startup PIN. The settings are considered optional. The following settings may be configured when this scenario is desired.

View the policies as a CSV which is easier to read than the table below and is also searchable.

Policy Path	Policy Name	Policy State	Policy Value	Registry Path	Registry Value Name	Registry Data Value	Applicable Client	Applicable Server	Required for Applicable OS
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Allow enhanced PINs for startup	Enabled		HKLM\Software\Policies\Microsoft\FVE	UseEnhancedPin	1	Windows 7+	Windows Server 2008 R2+	Yes
Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives	Configure minimum PIN length for startup	Enabled	6 or larger value	HKLM\Software\Policies\Microsoft\FVE	MinimumPIN	6 or larger	Windows 7+	Windows Server 2008 R2+	Yes

Administrators may need to configure BitLocker Network Unlock to ensure systems apply updates without requiring a user be physically present to enter a PIN at system boot.

BitLocker Group Policy

The Microsoft Security Compliance Toolkit contains BitLocker Group Policy Objects (GPO) for each Windows 10 operating system release's Windows Security Baseline. The GPOs can be used to configure and manage domain joined as well as standalone systems.

If using MBAM to configure and manage BitLocker on domain joined systems, then download the Microsoft Desktop Optimization Pack (MDOP) Group Policy templates since they contain the MBAM Group Policy settings.

Importing the BitLocker domain Group Policy

Use the PowerShell Group Policy commands to import the BitLocker Group Policy into a domain. Run the following command on a domain controller from a PowerShell prompt running as a domain administrator.

Invoke-ApplySecureHostBaseline -Path '.\Secure-Host-Baseline' -PolicyNames 'BitLocker'

Importing the AppLocker local Group Policy

Use Microsoft's LGPO tool to apply the BitLocker Group Policy to a standalone system. Run the following command from a command prompt running as a local administrator.

Invoke-ApplySecureHostBaseline -Path '.\Secure-Host-Baseline' -PolicyNames 'BitLocker' -ToolPath '.\LGPO\lgpo.exe'

Common issues

Conflicting BitLocker startup options

• Issue: Error message: The Group Policy settings for BitLocker startup options are in conflict and cannot be applied. Error code: 0x8031005B
• Explanation: The 'Require additional authentication at startup' policy description text can be misleading on how to correctly configure it.
• Resolution:
  1. Go to Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives
  2. Change the Require additional authentication at startup policy to configure all 4 dropdown menu options to Allow OR set 1 option to Require and the other 3 options to Do not allow.
  3. Run gpupdate /force from the command line.

Support for pre-boot PIN entry on tablets

• Issue: Error message: No pre-boot keyboard detected. The user may not be able to provide required input to unlock the volume. Error code: 0x803100B5
• Explanation: BitLocker checks if the system is a tablet. If it is a tablet, then BitLocker displays the above error message when trying to use a PIN protector. BitLocker doesn't check if the system supports a pre-boot keyboard. Some tablets may have a BIOS that supports a software keyboard. For example, the Dell Venue 11 Pro, Surface Pro 3, and Surface Pro 4 support entering a BitLocker PIN at pre-boot with a BIOS software keyboard. Some tablets may have detachable keyboard that works during pre-boot. For example, the Surface Pro 2 with firmware update from March 2014, Surface Pro 3, and Surface Pro 4 support entering a BitLocker PIN at pre-boot with their detachable keyboards. If the tablet does not support a BIOS software keyboard or a detachable keyboard that works during pre-boot, then configuring the below policy will require a USB keyboard be plugged into the tablet to enter a BitLocker PIN at pre-boot. Contact the OEM to inquire about tablet support for this specific scenario.
• Resolution:
  1. Go to Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption
  2. Set the Enable use of BitLocker authentication requiring preboot keyboard input on slates policy to Enabled.
  3. Run gpupdate /force from the command line.

License

See LICENSE.

Contributing

See CONTRIBUTING.

Disclaimer

See DISCLAIMER.