Network access: Restrict anonymous access to Named Pipes and Shares
Applies to
- Windows 11
- Windows 10
- Windows 8.1
- Windows Server 2022
- Windows Server 2019
- Windows Server 2016
- Windows Server 2012 R2
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 server pipes and shared folders 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'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
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 server pipes and shared folders that are listed in the NullSessionPipes and NullSessionShares entries.