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 
2013-12-02 (first published: 2013-11-18)
1,709 reads
DDL trigger will add a user to a newly created database and assign db_owner role. It can be modified for what role is required.
2015-03-12 (first published: 2013-08-22)
1,588 reads
A previous tip, SQL Server DDL Triggers to Track All Database Changes, generated a lot of discussion involving ways to make the provided DDL trigger more useful. Check out this tip to expand your knowledge on DDL Triggers.
2013-06-10
2,988 reads
In this tip Aaron Bertrand describes some of the ways in which you can extend the DDL trigger functionality.
2013-05-30
4,116 reads
DDL triggers enable us to audit DDL changes but there are a few missing events, design decisions and installation complications.
2010-08-17
7,698 reads