This requires acces as the ‘sa’ user. By default, you’ll be locked out after 3 failed attempts, so good luck with that 
– To allow advanced options to be changed.
EXEC sp_configure ’show advanced options’, 1
GO
– To update the currently configured value for advanced options.
RECONFIGURE
GO
– To enable the feature.
EXEC sp_configure ’xp_cmdshell’, 1
GO
– To update the currently configured value for this feature.
RECONFIGURE
GO
References:
