Revoke Execute access to the extended store procedure

DECLARE       @portNumber   NVARCHAR(10)

EXEC   xp_instance_regread

@rootkey    = 'HKEY_LOCAL_MACHINE',

@key        =

'Software\Microsoft\Microsoft SQL Server\MSSQLServer\SuperSocketNetLib\Tcp\IpAll',

@value_name = 'TcpDynamicPorts',

@value      = @portNumber OUTPUT

SELECT [Port Number] = @portNumber

GO

Due to the security reason we can disable the below two extended proc granted to the public role.

USE master

go

REVOKE EXECUTE ON xp_regread FROM public

REVOKE EXECUTE ON xp_instance_regread FROM public