Network access: Do not allow anonymous enumeration of SAM accounts and shares
Applies to
- Windows 10
Describes the best practices, location, values, and security considerations for the Network access: Do not allow anonymous enumeration of SAM accounts and shares security policy setting.
Reference
This policy setting determines which other permissions will be assigned for anonymous connections to the device. Windows allows anonymous users to perform certain activities, such as enumerating the names of domain accounts and network shares. This permission is convenient, for example, when an administrator wants to give access to users in a trusted domain that doesn't maintain a reciprocal trust. However, even with this policy setting enabled, anonymous users will have access to resources with permissions that explicitly include the built-in group, ANONYMOUS LOGON.
This policy setting has no impact on domain controllers. Misuse of this policy setting is a common error that can cause data loss or problems with data access or security.
Possible values
Enabled
Disabled
No other permissions can be assigned by the administrator for anonymous connections to the device. Anonymous connections will rely on default permissions. However, an unauthorized user could anonymously list account names and use the information to attempt to guess passwords or perform social-engineering attacks.
Not defined
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.
Policy conflicts
Even with this policy setting enabled, anonymous users will have access to resources with permissions that explicitly include the built-in group, ANONYMOUS LOGON (on systems earlier than Windows Server 2008 and Windows Vista).
Group Policy
This policy has no impact on domain controllers.
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
An unauthorized user could anonymously list account names and shared resources and use the information to attempt to guess passwords or perform social-engineering attacks.
Countermeasure
Enable the Network access: Do not allow anonymous enumeration of SAM accounts and shares setting.
Potential impact
It's impossible to grant access to users of another domain across a one-way trust because administrators in the trusting domain are unable to enumerate lists of accounts in the other domain. Users who access file and print servers anonymously are unable to list the shared network resources on those servers; the users must be authenticated before they can view the lists of shared folders and printers.