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V-278025

CAT II (Medium)

Windows Server 2025 must have the Server Message Block (SMB) v1 protocol disabled on the SMB client.

Rule ID

SV-278025r1182038_rule

STIG

Microsoft Windows Server 2025 Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-000381

Discussion

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.

Check Content

Different methods are available to disable SMBv1 on Windows Server 2025, if WN25-00-000380 is configured, this is not applicable.

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)

Fix Text

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".

Restart the system for the changes to take effect.

This policy setting 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.