Network access: Restrict anonymous access to Named Pipes and Shares

Applies to

  • Windows 10

Describes the best practices, location, values, policy management and security considerations for the Network access: Restrict anonymous access to Named Pipes and Shares security policy setting.

Reference

This policy setting enables or disables the restriction of anonymous access to only those shared folders and pipes that are named in the Network access: Named pipes that can be accessed anonymously and Network access: Shares that can be accessed anonymously settings. The setting controls null session access to shared folders on your computers by adding RestrictNullSessAccess with the value 1 in the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanManServer\Parameters. This registry value toggles null session shared folders on or off to control whether the Server service restricts unauthenticated clients' access to named resources.

Null sessions are a weakness that can be exploited through the various shared folders on the devices in your environment.

Possible values

  • Enabled
  • Disabled
  • Not defined

Best practices

  • Set this policy to Enabled. Enabling this policy setting restricts null session access to unauthenticated users to all server pipes and shared folders except those listed in the NullSessionPipes and NullSessionShares registry entries.

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 Enabled
DC Effective Default Settings Enabled
Member Server Effective Default Settings Enabled
Client Computer Effective Default Settings Enabled

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 are 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

Null sessions are a weakness that can be exploited through shared folders (including the default shared folders) on devices in your environment.

Countermeasure

Enable the Network access: Restrict anonymous access to Named Pipes and Shares setting.

Potential impact

You can enable this policy setting to restrict null-session access for unauthenticated users to all server pipes and shared folders except those that are listed in the NullSessionPipes and NullSessionShares entries.