Bangladesh Hackers group "3xp1r3 cyber army" hacked into the website belong to TeamGreyHat. Team Greyhat (TGH) is a hackers community who hacked lot of high profile websites.
"Dear Customer, You know that Joomla and Wordpress Site is hacked by through themes and exploits but we are the cr3ws of 3CA hacks team Greyhat CPanel without any exploit and it is a simple hack for us. And now indians are not underestimate us and see our pow3rwho we are. We accept your challenge and show you our power that never challenge us . One of our admin S1r-3xp1r3 warned you about your bug but you underestimate him. So we show you that you really have a bug :P////:)" Hacker said in defacement page.
This is not first time the Teamgreyhat.com being hacked. In past a hacker called "hunt" hacked into the official forum of Teamgreyhat. It seems that hackers didn't patch their own vulnerability.