What is this hacker trying to do?

Question

If you do a search for:

http://www.google.co.uk/search?q=0x57414954464F522044454C4159202730303A30303A313527&hl=en&start=30&sa=N

you will see a lot of

Answer 1

In simpler terms he/she/it is very slick. Using the "WAITFOR DELAY..." strategy allows he/she/it to see if the server is vulnerable without logging anything. The check is being done to see what access the connectionstring user has in the db. And like @Rook said, thT WOULD LEAD TO XP_CMDSHELL() which can give the intruder access to the server and even your network.