Windows Server 2025 must not allow anonymous enumeration of Security Account Manager (SAM) accounts.

Anonymous enumeration of SAM accounts allows anonymous logon 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: 0x00000001 (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".