How to quickly disable comments and creating nodes?

Just noticed that for the last two months, my web site is getting hammered - swamped by a large number of POST requests to create comments and new forum topics, which I had allowed for Anonymous users.

AWStats shows most of traffic is from China (!)

Is there a good way to quickly disable comments and node (forum) creation? Right now, I've to go into Permissions, and uncheck a bunch of rows. And then once this storm passes, will need to re-enable them.
That is tedious... is there any other way, or some alternative method, to quickly reject new comments and forum topics from Anonymous users?

(None of the postings made it on the site - were easily caught by spam catchers, which is why I never noticed this problem for 2 months.)