Accounts: Limit local account use of blank passwords to console logon only
Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options
Determines whether remote interactive logons by network services such as Terminal Services, Telnet, and FTP are allowed for local accounts that have blank passwords. If this setting is enabled, a local account must have a nonblank password to be used to perform an interactive logon from a remote client.
For more information, see: