This is not directly Oracle related, but probably still of interest.
SSH Password Brute Forcing may be on the Rise
Out of curiosity I pulled the ssh login attempts from /var/log/messages an internet facing server, and the data corresponds to what was shown in the article.
What was interesting was that all ssh attempts that I saw were for root. In the past when I have looked at these there are a number of different accounts being attacked, but now the attacks are all for root.