It's not just this site; MathOverflow, Stack Apps and Ask Ubuntu are under attack as well. Here is a list of those posts. SmokeDetector will cast four spam flags on all these posts (so only two by 'real' users are necessary to destroy the spam), but unfortunately it has a bit of a backlog right now so it might take a while to kick in.
♦ moderators can't do much other than flagging as spam as well; the Community Team can temporarily disable posting by unregistered accounts (though that doesn't help right now, as @Kulfy correctly notes) or try something else. Unfortunately, they have another far bigger problem at their hands at the moment, but I'll try to reach them about this.