The choice of dedicated / colo hosts can help; the budget places are fine for awhile, but when things go wrong, the savings rapidly evaporates ... some dedicated / colos are very strict about revealing login / acct info of accounts; really paranoid admins will go one step further and change the root password(s) to something even the dedicated host doesn't know - disadvantage of doing that though is they may not be able to fix some types of problems on their own.
In regards to vbulletin - the software itself is relatively secure, but many of the various plug-ins / addons aren't.
There honestly is little to no recourse for DNF against such actions; about all DNF can do legally is file a complaint with the FBI - they will likely ignore it due to small economic loss; they usually don't get involved until documented losses are significant ... ie. millions.
Realistically, DNF, and others affected, have limited options ... switching dedicated / colos, securing servers, updating software, etc along with relying on "alternative" methods of preventing repeats of such problems.
Ron