> In my access logs, they attempted to download all user records at once. This caused an error and no output was returned. I shut everything off soon after. If they scraped information through some other mechanism, I cannot say with any confidence either way.

Anyone with a large phpbb/vbulletin/xenforo install can tell you that the built-in GUI tools fail with even modest userbases. They just run mysql queries in a php request and hit the php.ini timeout, so you have to use CLI tools.

If all the attacker had access to was the forum front-end (rather than the machine) and they weren't particularly prepared, it wouldn't be surprising if they didn't achieve anything.