Some [ swearword removed by moderator. Grow up, that kind of language is not appropriate on this forum ] from somewhere just hacked our multisite install, which went live just some hours ago. I am no longer able to activate the chld the I used on the mother blog, just the default twenty twelve.
Nothing else has happened, as far as I can see.
Please, I need advice, where do I have to look in order to fix this?