Microsoft network client: Send unencrypted password to third-party SMB servers

  • Article

Applies to

  • Windows 11
  • Windows 10

Describes the best practices, location, values, policy management and security considerations for the Microsoft network client: Send unencrypted password to third-party SMB servers security policy setting.

Reference

The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. This policy setting allows or prevents the SMB redirector to send plaintext passwords to a non-Microsoft server service that doesn't support password encryption during authentication.

Possible values

  • Enabled

    The Server Message Block (SMB) redirector is allowed to send plaintext passwords to a non-Microsoft server service that doesn't support password encryption during authentication.

  • Disabled

    The Server Message Block (SMB) redirector only sends encrypted passwords to non-Microsoft SMB server services. If those server services don't support password encryption, the authentication request will fail.

  • Not defined

Best practices

  • It's advisable to set Microsoft network client: Send unencrypted password to connect to third-party SMB servers to Disabled.

Location

Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options

Default values

The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.

Server type or GPO Default value
Default Domain Policy Not defined
Default Domain Controller Policy Not defined
Stand-Alone Server Default Settings Disabled
DC Effective Default Settings Disabled
Member Server Effective Default Settings Disabled
Client Computer Effective Default Settings Disabled

Policy management

This section describes features and tools that are available to help you manage this policy.

Restart requirement

None. Changes to this policy become effective without a device restart when they're saved locally or distributed through Group Policy.

Security considerations

This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.

Vulnerability

If you enable this policy setting, the server can transmit plaintext passwords across the network to other computers that offer SMB services. These other devices might not use any of the SMB security mechanisms that are included with Windows Server 2003 or later.

Countermeasure

Disable the Microsoft network client: Send unencrypted password to connect to third-party SMB servers setting.

Potential impact

Some older applications may not be able to communicate with the servers in your organization through the SMB protocol.