At the time that yuezhi reported, there was yet another attempt on the site.
So, we took the site down. And I went totally mental on not just the forums files, but all files everywhere.
3hrs later, We finally got cleaned (roughly 140+) files across the board. HTML <HEAD> elements got cleaned up, PHP files that had injected code cleaned, .JS files were repaired and some really old files from as far back as 2009 were sanitized. rev_posix established a stricter set of directory level permissions, and we are back in business.
And counting down until the next time this takes place. Because I can't and won't trust that it wont without absolutely rebuilding everything. But that will take time, so we'll be looking into how we can accomplish that and try and schedule a when.
In the meantime, we'll just try and keep the lights on. I should be able to get something in place in the next couple of weeks that should allow for new users to the Wiki (legitimate ones this time) and we'll go from there and deal with what ever crops up as it happens.
In the meantime, my apologies at the disturbing frequency of our downtime.