Microsoft Smbv1 Vulnerability

In this article

Applies to: Windows 10, Windows 8.1, Windows 8, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server 2012

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.

Đang xem: Smbv1 is not installed by default in windows 10 version 1709, windows server version 1709 and later versions

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.

Disabling SMBv2 or SMBv3 for troubleshooting

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.

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In Windows 10, Windows 8.1, and Windows 8, 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 failoverScale 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 serverSMB Direct – adds RDMA networking support for high performance, with low latency and low CPU useEncryption – Provides end-to-end encryption and protects from eavesdropping on untrustworthy networksDirectory Leasing – Improves application response times in branch offices through cachingPerformance Optimizations – optimizations for small random read/write I/O

In Windows 7 and Windows Server 2008 R2, disabling SMBv2 deactivates the following functionality:

Request compounding – allows for sending multiple SMBv2 requests as a single network requestLarger reads and writes – better use of faster networksCaching of folder and file properties – clients keep local copies of folders and filesDurable handles – allow for connection to transparently reconnect to the server if there”s a temporary disconnectionImproved message signing – HMAC SHA-256 replaces MD5 as hashing algorithmImproved scalability for file sharing – number of users, shares, and open files per server greatly increasedSupport for symbolic linksClient oplock leasing model – limits the data transferred between the client and server, improving performance on high-latency networks and increasing SMB server scalabilityLarge MTU support – for full use of 10 Gigabit Ethernet (GbE)Improved energy efficiency – clients that have open files to a server can sleep

The SMBv2 protocol was introduced in Windows Vista and Windows Server 2008, while the SMBv3 protocol was introduced in Windows 8 and Windows Server 2012. For more information about SMBv2 and SMBv3 capabilities, see the following articles:

How to remove SMBv1

Here”s how to remove SMBv1 in Windows 10, Windows 8.1, Windows Server 2019, Windows Server 2016, and Windows 2012 R2.

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PowerShell methodsSMBv1 (client and server)


Get-WindowsOptionalFeature -Online -FeatureName smb1protocolDisable:

Disable-WindowsOptionalFeature -Online -FeatureName smb1protocolEnable:

Enable-WindowsOptionalFeature -Online -FeatureName smb1protocolWindows Server 2012 R2, Windows Server 2016, Windows Server 2019: Server Manager method for disabling SMBSMBv1


To remove SMBv1 from Windows Server:

On the Server Manager Dashboard of the server where you want to remove SMBv1, under Configure this local server, select Add roles and features.On the Before you begin page, select Start the Remove Roles and Features Wizard, and then on the following page, select Next.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.On the Remove server roles page, select Next.On the Remove features page, clear the check box for SMB 1.0/CIFS File Sharing Support and select Next.On the Confirm removal selections page, confirm that the feature is listed, and then select Remove.Windows 8.1 and Windows 10: PowerShell methodSMBv1 Protocol


Get-WindowsOptionalFeature -Online -FeatureName SMB1ProtocolDisable:

Disable-WindowsOptionalFeature -Online -FeatureName SMB1ProtocolEnable:

Enable-WindowsOptionalFeature -Online -FeatureName SMB1ProtocolSMBv2/v3 Protocol (only disables SMBv2/v3 Server)Detect:

Get-SmbServerConfiguration | Select EnableSMB2ProtocolDisable:

Set-SmbServerConfiguration -EnableSMB2Protocol $falseEnable:

Set-SmbServerConfiguration -EnableSMB2Protocol $trueWindows 8.1 and Windows 10: Add or Remove Programs method


To disable SMBv1 on Windows 8.1 and Windows 10:

In Control Panel, select Programs and Features.Under Control Panel Home, select Turn Windows features on or off to open the Windows Features box.In the Windows Features box, scroll down the list, clear the check box for SMB 1.0/CIFS File Sharing Support and select OK.After Windows applies the change, on the confirmation page, select Restart now.

How to detect status, enable, and disable SMB protocols on the SMB Server

For Windows 8 and Windows Server 2012

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. 

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