Information
The sa account is a widely known and often widely used SQL Server account with sysadmin privileges. This is the original login created during installation and always has the principal_id=1 and sid=0x01
Enforcing this control reduces the probability of an attacker executing brute force attacks against a well-known principal.
Solution
Execute the following T-SQL query:
USE [master]
GO
DECLARE @tsql nvarchar(max)
SET @tsql = 'ALTER LOGIN ' + SUSER_NAME(0x01) + ' DISABLE'
EXEC (@tsql)
GO
Impact:
It is not a good security practice to code applications or scripts to use the sa account. However, if this has been done, disabling the sa account will prevent scripts and applications from authenticating to the database server and executing required tasks or functions.