Anonymous enumeration of SAM accounts must not be allowed.

Anonymous enumeration of SAM accounts allows anonymous log on users (null session connections) to list all accounts names, thus providing a list of potential points to attack the system.

If the following registry value does not exist or is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Control\Lsa\

Value Name: RestrictAnonymousSAM

Value Type: REG_DWORD Value: 1

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network access: Do not allow anonymous enumeration of SAM accounts" to "Enabled".