The Server Message Block (SMB) v1 protocol must be disabled on the SMB client.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-73523	WN12-00-000180	SV-88205r2_rule		Medium

Description
SMBv1 is a legacy protocol that uses the MD5 algorithm as part of SMB. MD5 is known to be vulnerable to a number of attacks such as collision and preimage attacks as well as not being FIPS compliant. Disabling SMBv1 support may prevent access to file or print sharing resources with systems or devices that only support SMBv1. File shares and print services hosted on Windows Server 2003 are an example, however Windows Server 2003 is no longer a supported operating system. Some older network attached devices may only support SMBv1.

Description

SMBv1 is a legacy protocol that uses the MD5 algorithm as part of SMB. MD5 is known to be vulnerable to a number of attacks such as collision and preimage attacks as well as not being FIPS compliant. Disabling SMBv1 support may prevent access to file or print sharing resources with systems or devices that only support SMBv1. File shares and print services hosted on Windows Server 2003 are an example, however Windows Server 2003 is no longer a supported operating system. Some older network attached devices may only support SMBv1.

STIG	Date
Windows Server 2012/2012 R2 Member Server Security Technical Implementation Guide	2020-06-16

Details

Check Text ( C-75995r1_chk )
This requirement specifically applies to Windows 2012 but can also be used for Windows 2012 R2. Different methods are available to disable SMBv1 on Windows 2012 R2, if V-73805 is configured on Windows 2012 R2, this is NA. If the following registry value is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Services\mrxsmb10\ Value Name: Start Type: REG_DWORD Value: 0x00000004 (4) If the following registry value includes MRxSmb10, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Services\LanmanWorkstation\ Value Name: DependOnService Type: REG_MULTI_SZ Value: Default values after removing MRxSmb10 include the following, which are not a finding: Bowser MRxSmb20 NSI

Check Text ( C-75995r1_chk )

This requirement specifically applies to Windows 2012 but can also be used for Windows 2012 R2.

Different methods are available to disable SMBv1 on Windows 2012 R2, if V-73805 is configured on Windows 2012 R2, this is NA.

If the following registry value is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SYSTEM\CurrentControlSet\Services\mrxsmb10\

Value Name: Start

Type: REG_DWORD
Value: 0x00000004 (4)

If the following registry value includes MRxSmb10, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SYSTEM\CurrentControlSet\Services\LanmanWorkstation\

Value Name: DependOnService

Type: REG_MULTI_SZ
Value: Default values after removing MRxSmb10 include the following, which are not a finding:
Bowser
MRxSmb20
NSI

Fix Text (F-82947r1_fix)
Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Configure SMBv1 client driver" to "Enabled" with "Disable driver (recommended)" selected for "Configure MrxSmb10 driver". Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Configure SMBv1 client (extra setting needed for pre-Win8.1/2012R2)" to "Enabled" with the following three lines of text entered for "Configure LanmanWorkstation Dependencies": Bowser MRxSmb20 NSI The system must be restarted for the changes to take effect. These policy settings requires the installation of the SecGuide custom templates included with the STIG package. "SecGuide.admx" and "SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.

Fix Text (F-82947r1_fix)

Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Configure SMBv1 client driver" to "Enabled" with "Disable driver (recommended)" selected for "Configure MrxSmb10 driver".

Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Configure SMBv1 client (extra setting needed for pre-Win8.1/2012R2)" to "Enabled" with the following three lines of text entered for "Configure LanmanWorkstation Dependencies":
Bowser
MRxSmb20
NSI

The system must be restarted for the changes to take effect.

These policy settings requires the installation of the SecGuide custom templates included with the STIG package. "SecGuide.admx" and "SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.