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Jun 8, 2020 · Over the years, SMB has evolved through three major versions – SMBv1, SMBv2, and SMBv3 – each bringing significant improvements in performance, scalability, and security. In this article, we'll explore the differences between these versions, their impact on network security, and how to analyze SMB traffic using Wireshark.
May 1, 2024 · For SMBv1, use the filter smb, for SMBv2, use smb2, and for SMBv3, use smb2 && smb2.cmd == 0x11. Understanding the differences between SMB versions is crucial for securing your network.
- Overview
- Disabling SMBv2 or SMBv3 for troubleshooting
- How to remove SMBv1 via PowerShell
- How to detect status, enable, and disable SMB protocols
- Disable SMBv1 by using Group Policy
This article describes how to enable and disable Server Message Block (SMB) version 1 (SMBv1), SMB version 2 (SMBv2), and SMB version 3 (SMBv3) on the SMB client and server components.
While disabling or removing SMBv1 might cause some compatibility issues with old computers or software, SMBv1 has significant security vulnerabilities, and we strongly encourage you not to use it. SMB 1.0 isn't installed by default in any edition of Windows 11 or Windows Server 2019 and later. SMB 1.0 also isn't installed by default in Windows 10, except Home and Pro editions. We recommend that instead of reinstalling SMB 1.0, you update the SMB server that still requires it. For a list of third parties that require SMB 1.0 and their updates that remove the requirement, review the SMB1 Product Clearinghouse.
We recommend keeping SMBv2 and SMBv3 enabled, but you might find it useful to disable one temporarily for troubleshooting. For more information, see How to detect status, enable, and disable SMB protocols on the SMB Server.
In Windows 10, Windows 8.1, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, and Windows Server 2012, disabling SMBv3 deactivates the following functionality:
•Transparent Failover - clients reconnect without interruption to cluster nodes during maintenance or failover
•Scale Out - concurrent access to shared data on all file cluster nodes
•Multichannel - aggregation of network bandwidth and fault tolerance if multiple paths are available between client and server
•SMB Direct - adds RDMA networking support for high performance, with low latency and low CPU use
Windows Server 2012 Windows Server 2012 R2, Windows Server 2016, Windows Server 2019: Server Manager method
To remove SMBv1 from Windows Server: 1.On the Server Manager Dashboard of the server where you want to remove SMBv1, under Configure this local server, select Add roles and features. 2.On the Before you begin page, select Start the Remove Roles and Features Wizard, and then on the following page, select Next. 3.On the Select destination server page under Server Pool, ensure that the server you want to remove the feature from is selected, and then select Next. 4.On the Remove server roles page, select Next. 5.On the Remove features page, clear the check box for SMB 1.0/CIFS File Sharing Support and select Next. 6.On the Confirm removal selections page, confirm that the feature is listed, and then select Remove.
Windows 8.1, Windows 10, and Windows 11: Add or Remove Programs method
To disable SMBv1 for the mentioned operating systems: 1.In Control Panel, select Programs and Features. 2.Under Control Panel Home, select Turn Windows features on or off to open the Windows Features box. 3.In the Windows Features box, scroll down the list, clear the check box for SMB 1.0/CIFS File Sharing Support and select OK. 4.After Windows applies the change, on the confirmation page, select Restart now.
•Server
•Client
Windows 8 and Windows Server 2012 introduced the new Set-SMBServerConfiguration Windows PowerShell cmdlet. The cmdlet enables you to enable or disable the SMBv1, SMBv2, and SMBv3 protocols on the server component.
You don't have to restart the computer after you run the Set-SMBServerConfiguration cmdlet.
SMBv1
This procedure configures the following new item in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters •Registry entry: SMB1 •REG_DWORD: 0 = Disabled To use Group Policy to configure this, follow these steps: 1.Open the Group Policy Management Console. Right-click the Group Policy object (GPO) that should contain the new preference item, and then click Edit. 2.In the console tree under Computer Configuration, expand the Preferences folder, and then expand the Windows Settings folder. 3.Right-click the Registry node, point to New, and select Registry Item. In the New Registry Properties dialog box, select the following: •Action: Create •Hive: HKEY_LOCAL_MACHINE •Key Path: SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters •Value name: SMB1 •Value type: REG_DWORD •Value data: 0
SMB v1
To disable the SMBv1 client, the services registry key needs to be updated to disable the start of MRxSMB10, and then the dependency on MRxSMB10 needs to be removed from the entry for LanmanWorkstation so that it can start normally without requiring MRxSMB10 to first start. This guidance updates and replaces the default values in the following two items in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\mrxsmb10 Registry entry: Start REG_DWORD: 4= Disabled HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation Registry entry: DependOnService REG_MULTI_SZ: "Bowser","MRxSmb20″,"NSI" To configure this by using Group Policy, follow these steps: 1.Open the Group Policy Management Console. Right-click the GPO that should contain the new preference item, and then click Edit. 2.In the console tree under Computer Configuration, expand the Preferences folder, and then expand the Windows Settings folder. 3.Right-click the Registry node, point to New, and select Registry Item. 4.In the New Registry Properties dialog box, select the following: •Action: Update •Hive: HKEY_LOCAL_MACHINE •Key Path: SYSTEM\CurrentControlSet\services\mrxsmb10 •Value name: Start •Value type: REG_DWORD •Value data: 4 5.Then remove the dependency on the MRxSMB10 that was disabled. In the New Registry Properties dialog box, select the following: •Action: Replace •Hive: HKEY_LOCAL_MACHINE •Key Path: SYSTEM\CurrentControlSet\Services\LanmanWorkstation •Value name: DependOnService •Value type: REG_MULTI_SZ •Value data: •Bowser •MRxSmb20 •NSI 6.Restart the targeted systems to finish disabling SMB v1.
Auditing SMBv1 usage
To determine which clients are attempting to connect to an SMB server with SMBv1, you can enable auditing on Windows Server 2016, Windows 10, and Windows Server 2019. You can also audit on Windows 7 and Windows Server 2008 R2 if the May 2018 monthly update is installed, and on Windows 8.1 and Windows Server 2012 R2 if the July 2017 monthly update is installed. •Enable: •Disable: •Detect:
Dec 17, 2018 · While SMB 2 and SMB 3 have huge advantages over SMB 1, their main disadvantage is that if you turn them off, things will go downhill for you in a hurry. Here’s a short list of what you lose if you try to disable SMB 2 and 3:
Sep 15, 2021 · When comparing to SMBv1, SMB version 2 introduced performance improvements, symbolic links and SHA-256 message signing in 2006 with Windows Vista. SMBv2 offers a much better alternative than SMBv1, but still SMBv3 is the version you’d want to see negotiated.
Apr 19, 2022 · While SMB signing has been there since SMB 1.0, it has evolved over time to meet modern security needs. SMB 1.0 supported MD5-based message signing, and SMB 3.1.1 supports AES CMAC-based signing. Note that signing is not the same as encryption.
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There are a few different versions – SMBv1, SMBv2, and SMBv3 – each with their own unique capabilities and security profiles. In this comprehensive guide, I‘ll give you the complete low-down on detecting which SMB editions you have enabled, turning them on or off, and optimizing your configurations for performance and safety.
