Purpose: Restrict to Create / Alter logins with blank passwords irrespective of "Enforce password security" enabled / disabled.
Execute the above script . Try to Create / Alter password with a blank password. It will not allow you to create the same.
If anyone has a better solution, then please free to contact me.
CREATE TRIGGER Trg_EnforceNoBlankPassword
on ALL SERVER
FOR CREATE_LOGIN, ALTER_LOGIN
AS
BEGIN
DECLARE @ObjName AS VARCHAR(256), @PWD AS VARCHAR(256)
SELECT @ObjName = EVENTDATA().value('(/EVENT_INSTANCE/ObjectName )[1]','nvarchar(max)')
SELECT @Pwd = PWDCOMPARE('',PASSWORD)
FROM master..syslogins
WHERE Name = @ObjName
IF @PWD = 1
BEGIN
RAISERROR ('PASSWORD CANNOT BE BLANK' , 18, 1)
ROLLBACK
END
END 
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