I spoke to barracuda too. We are having the same issues. They told us the engineers are working on it, but so far no improvement.
We've had 400s, first physical then virtual, for going on 15 years and we've NEVER seen so much blatant spam getting through. It all has the same traits/characteristics, obviously coming from the same origin, so I am perplexed as to why after weeks of this, Barracuda can't get this stuff filtered out. We have 2000+ users, and a big % are getting hit hard. We are getting complaints hourly from our users.
Please folks, FIX THE SPAM GETTING THRU.