It would probably require a massive update of the forum period.
Basically a new system of having a forum, new format, the whole works.
In that new but now 'normal' forum format, the software would have the ability to combat such heavy spamming.
This old system (that you are looking at right now), that is quite unique, does not have the ability to add on spam detection packages.
This was predictable. It was just a matter of time.
The posting of spam can be done by bots, and the forum software as it exists now, would not be able to prevent it.