Microsoft released a new whitepaper this week that gives an insight in why you should protect your privileged accounts. One of the techniques described is the PassTheHash attack which is a sophisticated attack but fairly easy to execute. These attacks have been seen in the “field” and are being used today.
If you work with active directory, if you do not have a very strict control over administrative groups, read it, shiver and make sure to protect to the maximum extend if you think your companies assets should be protected.